阅读说明：本技术 系统开关电源装置 (System switching power supply device ) 是由 细谷达也 于 2019-12-09 设计创作，主要内容包括：本发明提供一种能够兼顾对多个功率变换电路集中控制整体的动作的公共运算控制和输出电压的高速负载响应的电源装置。多个功率变换部(31-34)具备多个电感器L、开关电路(400)和单独模拟控制部。MPU(20)能够执行可编程的运算处理,并对多个功率变换部(31-34)输出振荡控制信号。公共输出端子(Pout)被并联地连接多个功率变换部(31-34)的输出部,并与负载连接。单独模拟控制部由模拟电子电路形成,具备反馈信号生成部(50)以及驱动部(40)。反馈信号生成部(50)对多个功率变换部(31-34)的输出部的状态进行检测,并生成反馈到多个功率变换部(31-34)的反馈信号。驱动部(40)对开关电路(400)的开关元件(Q1、Q2)进行驱动。(The invention provides a power supply device capable of achieving both common operation control for collectively controlling the overall operation of a plurality of power conversion circuits and high-speed load response of an output voltage. The plurality of power conversion units (31-34) are provided with a plurality of inductors (L), a switching circuit (400), and a single analog control unit. The MPU (20) can execute programmable arithmetic processing and output oscillation control signals to the plurality of power conversion units (31-34). The common output terminal (Pout) is connected in parallel to the output units of the plurality of power conversion units (31-34) and is connected to a load. The individual analog control unit is formed of an analog electronic circuit and is provided with a feedback signal generation unit (50) and a drive unit (40). A feedback signal generation unit (50) detects the state of the output units of the plurality of power conversion units (31-34), and generates feedback signals to be fed back to the plurality of power conversion units (31-34). The drive unit (40) drives the switching elements (Q1, Q2) of the switching circuit (400).)

1. A system switching power supply device includes:

a plurality of power conversion units each including an inductor, a switching circuit, and an individual analog control unit;

a common control unit that outputs oscillation control signals to the plurality of power conversion circuits; and

a common output terminal connected in parallel to the output units of the plurality of power conversion units and connected to a load,

the individual analog control unit is formed by an analog electronic circuit, and includes:

a feedback signal generating unit that detects a state of an output unit of the plurality of power conversion units and generates a feedback signal to be fed back to the plurality of power conversion units; and

a driving unit that drives the switching element of the switching circuit,

the common control section is formed of a digital electronic circuit capable of executing programmable arithmetic processing.

2. The system switching power supply apparatus according to claim 1,

the individual analog control section is provided with a pulse width modulation control IC,

the common control unit generates an oscillation signal by arithmetic processing capable of programmably setting a phase of a switching frequency in accordance with the number of the plurality of power conversion units, and outputs the oscillation signal to the individual analog control unit.

3. The system switching power supply apparatus according to claim 1 or claim 2,

the feedback signal generation unit includes:

a common node connecting the plurality of power conversion units in parallel;

an individual current signal generating unit that generates an individual current signal based on the current of the inductor of the plurality of power conversion units;

a common signal generation unit that generates a common bus signal that flows to the common node from the individual current signals for the plurality of power conversion units; and

and an individual current feedback signal generating unit that generates an individual current feedback signal based on a difference between the individual current signal and the common bus signal, and outputs the individual current feedback signal as the feedback signal.

4. The system switching power supply apparatus according to claim 3,

the common signal generating unit generates the common bus signal using a maximum value of the individual current signals for the plurality of power converting units.

5. The system switching power supply apparatus according to claim 3,

the common signal generation unit generates the common bus signal using an average value of the individual current signals for the plurality of power conversion units.

6. The system switching power supply apparatus according to any one of claim 3 to claim 5,

the feedback signal generation unit includes: an individual voltage feedback signal generating section for generating an individual voltage feedback signal based on a voltage of the common output terminal,

feeding back a signal obtained by adding the individual current feedback signal and the individual voltage feedback signal to the plurality of power conversion circuits as the feedback signal.

7. The system switching power supply apparatus according to any one of claim 3 to claim 6,

the feedback signal generating section outputs the common bus signal to the common control section as an operation number signal,

the common control unit sets an individual operation of the plurality of power conversion units using the operation number signal, and outputs the oscillation control signal including the setting of the individual operation.

8. The system switching power supply apparatus according to any one of claim 1 to claim 7,

the disclosed device is provided with: an inductor current detection circuit that detects a current of the inductor,

the inductor current detection circuit includes: a detection capacitor and a detection resistor, which constitute a CR time constant having a predetermined relationship with respect to a specific inductance and a specific AC resistance at a switching frequency of the inductor,

a series circuit of the detection resistor and the detection capacitor is connected in parallel to the inductor,

and generating an output signal according to the voltage at the two ends of the capacitor for detection.

9. The system switching power supply apparatus according to any one of claim 1 to claim 8,

the common control unit outputs a control signal including oscillation signals in which phases of switching frequencies are shifted from each other to the plurality of power conversion units.

10. The system switching power supply apparatus according to any one of claim 1 to claim 9,

the common control unit executes signal processing in accordance with an external command signal connected to the common output terminal, and sets the operation of the individual analog control units of the plurality of power conversion units.

11. The system switching power supply apparatus according to any one of claim 1 to claim 10,

the switching circuit and the separate analog control section include an FET built-in PWM control IC that is integrally integrated.

12. The system switching power supply apparatus according to any one of claim 1 to claim 11,

the common control section includes a programmable microprocessor.

Technical Field

The present invention relates to a switching power supply device having a configuration in which a plurality of power conversion units each including a switching circuit are connected in parallel.

Background

Currently, a low-voltage and large-current switching power supply device is required. As a switching power supply device that realizes a low voltage and a large current, for example, patent document 1 and patent document 2 describe a switching power supply circuit called a multiphase converter.

The multiphase converter has a plurality of power conversion units. The plurality of power conversion units are connected in parallel, for example. The multiphase converter outputs the output currents of the plurality of power conversion units together, thereby realizing a large current. In addition, the multiphase converter increases the operating frequency on the surface by shifting the phases of the switching frequencies with respect to the plurality of power conversion units, thereby reducing the size of the output smoothing circuit and stabilizing the output voltage and the output current.

Prior art documents

Patent document

Patent document 1: japanese patent laid-open publication No. 2011-147269

Patent document 2: japanese patent laid-open publication No. 2013-94058

Disclosure of Invention

Problems to be solved by the invention

The state of the load connected to the switching power supply device changes with time according to the operation of the load circuit and the like, and the load current and the power consumption change with time. In this case, it is necessary to stabilize the output voltage to be constant without changing even with respect to a sudden change in the load current. Therefore, it is necessary to detect the output voltage of the power conversion circuit and feed it back to the control circuit that controls the switching operation, and to realize a negative feedback control operation so that the output voltage becomes a constant value.

However, if the control circuit for controlling the switching operation is implemented by a digital electronic circuit, a time for arithmetic processing is required in the digital electronic circuit, and it is difficult to control the output voltage to a stable constant value in response to a rapid change in the load current with a high-speed load. Further, since the power conversion circuit itself is an analog electronic circuit, a large number of analog-to-digital converters are required as interfaces between the analog power conversion circuit and the digital power conversion circuit. Therefore, the control circuit becomes large and complicated, and has a problem that it becomes very expensive due to its large size. On the other hand, if the control circuit for controlling the switching operation is implemented by an analog electronic circuit, an analog control circuit corresponding to the number of power conversion units is required, and the control circuit becomes large and complicated, and becomes large in size and very expensive.

Therefore, an object of the present invention is to provide a system switching power supply device capable of achieving both common operation control for controlling a plurality of power conversion circuits and high-speed load response of an output voltage.

Means for solving the problems

A switching power supply device of the present invention includes a plurality of power conversion units, a common control unit, and a common output terminal.

The plurality of power conversion units each include an inductor, a switching circuit, and an individual analog control unit. The common control unit can execute programmable arithmetic processing and output oscillation control signals to the plurality of power conversion circuits. The common output terminal is connected in parallel to the output units of the plurality of power conversion units and is connected to a load. The individual analog control unit is formed of an analog electronic circuit and includes a feedback signal generation unit and a drive unit. The feedback signal generating unit detects the state of the output units of the plurality of power converting units, and generates feedback signals to be fed back to the plurality of power converting units. The driving unit drives a switching element of the switching circuit.

In this configuration, an analog electronic circuit is used for a circuit portion which requires high-speed responsiveness, and a digital electronic circuit is used for a circuit portion which requires programmable processing.

Effects of the invention

According to the present invention, it is possible to achieve both digital control for performing common arithmetic control for collectively controlling the overall operation of a plurality of power conversion units and analog control for realizing high-speed load response of an output voltage, and it is possible to achieve high efficiency, miniaturization, and noise reduction of a system switching power supply device including a plurality of power conversion units.

Drawings

Fig. 1 is a circuit block diagram of a switching power supply device 10 according to embodiment 1.

Fig. 2 is an equivalent circuit diagram of a measuring circuit of the inductor current.

Fig. 3 is a circuit diagram of feedback signal generating unit 50 according to embodiment 1.

Fig. 4 is a functional block diagram of the MPU20 according to embodiment 1.

Fig. 5 is a diagram for explaining a concept of switching of the operation numbers.

Fig. 6 is a flowchart showing the switching process of the operation number.

Fig. 7 is a circuit block diagram of the switching power supply device 10A according to embodiment 2.

Fig. 8 is a circuit diagram of feedback signal generating unit 50A according to embodiment 2.

Fig. 9 is a functional block diagram of the MPU20A according to embodiment 2.

Fig. 10 is a circuit block diagram of the switching power supply device 10B according to embodiment 3.

Fig. 11 is a circuit block diagram of a feedback signal generating unit 50R of the switching power supply device according to embodiment 4.

Fig. 12 is a circuit diagram of a circuit for detecting an inductor current of the switching power supply device according to embodiment 5.

Detailed Description

(embodiment 1)

A switching power supply device according to embodiment 1 of the present invention will be described with reference to the drawings. Fig. 1 is a circuit block diagram of a switching power supply device 10 according to embodiment 1.

As shown in fig. 1, the switching power supply device 10 includes an MPU20, a power conversion unit 31, a power conversion unit 32, a power conversion unit 33, and a power conversion unit 34. Although the number of power conversion units is 4 in the present embodiment, the configuration of the present embodiment can be applied to a plurality of power conversion units. The switching power supply device 10 includes an input terminal Pin and an output terminal Pout. The switching power supply device 10 corresponds to the "system switching power supply device" of the present invention, and the output terminal Pout corresponds to the "common output terminal" of the present invention, the voltage of which is the output voltage Vout. The system switching power supply device is, for example, different from a switching power supply including only one power conversion unit, and means a power supply device including a plurality of power conversion units and appropriately controlling the number of operations and the operating state of the plurality of power conversion units in accordance with the state of a load.

The input terminal Pin is connected to an external dc voltage source. The switching power supply device 10 receives a dc input voltage Vin from an input terminal Pin. The output terminal Pout is connected to a load not shown.

The MPU20 is connected to the input terminal Pin, and is supplied with power via the input terminal Pin. The power supply line thereof is connected to the ground reference potential via an input capacitor Ci 1.

The MPU20 is a programmable Micro Processing Unit (Micro Processing Unit) that is formed of digital electronic circuits. The MPU20 is a device capable of executing programmable arithmetic processing. The MPU20 generates a control signal (oscillation control signal) by programmable arithmetic processing.

The MPU20 is connected to the power conversion unit 31, the power conversion unit 32, the power conversion unit 33, and the power conversion unit 34. The MPU20 outputs control signals to each of the power conversion unit 31, the power conversion unit 32, the power conversion unit 33, and the power conversion unit 34.

For example, the MPU20 outputs a control signal corresponding to an operating power conversion unit (power conversion unit that enables operation) among the plurality of power conversion units, and does not output a control signal to a non-operating power conversion unit (power conversion unit that disables operation).

The control signal includes an oscillation signal including a switching frequency of each power conversion unit. The oscillation signals of the control signals have a phase difference, and the phase difference is set according to the number of the operating power conversion units. Thus, the MPU20 operates the switching power supply device 10 as a multiphase converter.

At this time, the MPU20 determines the number of operating power conversion units using the operation number signal Sop from the terminal 504. Terminal 504 of power conversion unit 31, terminal 504 of power conversion unit 32, terminal 504 of power conversion unit 33, and terminal 504 of power conversion unit 34 are connected to common node 540, and common node 540 is connected to MPU 20. The MPU20 determines the phase difference from the number, and sets the oscillation signal to be output to the operating power conversion unit.

Power conversion unit 31, power conversion unit 32, power conversion unit 33, and power conversion unit 34 are connected to input terminal Pin, and are supplied with power via input terminal Pin. The power supply line of the power conversion unit 31 is connected to the ground reference potential via an input capacitor Ci 1. The power supply line of the power conversion unit 32 is connected to the ground reference potential via an input capacitor Ci 2. The power supply line of the power converter 33 is connected to the ground reference potential via an input capacitor Ci 3. The power supply line of the power converter 34 is connected to the ground reference potential via an input capacitor Ci 4.

The output terminal Pout is connected to the output terminal of the power conversion unit 31, the output terminal of the power conversion unit 32, the output terminal of the power conversion unit 33, and the output terminal of the power conversion unit 34.

Power conversion unit 31, power conversion unit 32, power conversion unit 33, and power conversion unit 34 have the same circuit configuration. Therefore, the circuit configuration will be described below in detail only for the power conversion unit 31.

As shown in fig. 1, the power conversion unit 31 includes an inductor L, an output capacitor Co1, a resistor RL, a capacitor CL, a PWM control IC400, and a feedback signal generation unit 50.

The circuit including the switching element Q1 and the switching element Q2 corresponds to a "switching circuit" of the present invention. The PWM control IC400 includes a driving unit 40, a switching element Q1, and a switching element Q2. The PWM control IC400 includes an integrally integrated FET. That is, the PWM control IC400 is an analog IC. The PWM control IC400 corresponds to "FET built-in PWM control IC" and "pulse width modulation control IC".

The PWM control IC400 is connected to the input terminal Pin, and is supplied with power via the input terminal Pin.

The MPU20 inputs a control signal to the drive unit 40. A synthesized feedback signal of the voltage feedback signal and the current feedback signal is input to the driving unit 40. The driver 40 generates a switching control signal using PWM (pulse width modulation) control for the switching element Q1 and the switching element Q2 based on the control signal and the synthesized feedback signal.

The switching element Q2 has a gate connected to the driver 40, a drain connected to the input terminal Pin, and a source connected to the drain of the switching element Q1. The switching element Q1 has a gate connected to the driver 40 and a source connected to the ground reference potential. A circuit including these switching element Q1 and switching element Q2 corresponds to a "switching circuit" of the present invention.

A switching control signal for the switching element Q2 is input from the driving unit 40 to the gate of the switching element Q2. A switching control signal for the switching element Q1 is input from the driving unit 40 to the gate of the switching element Q1.

One end of the inductor L is connected to a connection point between the source of the switching element Q2 and the drain of the switching element Q2.

The other end of the inductor L is connected to the output terminal Pout. The other end of the inductor L is connected to the ground reference potential via an output capacitor Co 1.

(detection circuit of inductor Current iL)

A series circuit of the resistor RL and the capacitor CL is connected in parallel with the inductor L. This circuit corresponds to the "inductor current detection circuit" of the present invention. The resistance RL corresponds to a "detection resistance" having an "ac resistance" of the present invention, and the capacitor CL corresponds to a "detection capacitor" of the present invention. By setting the inductance of the inductor L, the resistance value of the equivalent series resistance Rs of the inductor L, the resistance value of the resistance RL, and the capacitance of the capacitor CL in a specific relationship, the current flowing through the inductor L can be detected without loss.

Specifically, the current of the inductor L (inductor current iL) can be detected without loss according to the following principle. Fig. 2 is an equivalent circuit diagram of a measuring circuit of the inductor current.

The inductor L has an equivalent series resistance Rs. Therefore, the series circuit of the resistance RL and the capacitor CL can be regarded as being connected in parallel with respect to the series circuit of the inductor L and the equivalent series resistance Rs.

Here, the voltage across the capacitor CL is vC. At this time, the side of capacitor CL connected to resistor RL is set to the + side. Further, the voltage across the equivalent series resistance Rs is vs. At this time, the side of the equivalent series resistance Rs connected to the inductor L is set to the + side.

In this case, if il (t) is an inductor current as a function of time t and E is an applied voltage to the circuit, vs can be expressed by equation 1 as a function of time t.

vs (t) il (t) Rs (E/L) t Rs- (formula 1)

On the other hand, vC can be represented by equation 2 as a function of time t, in the vicinity of t being 0.

vc (t) ═ E/(CL · RL)). t- (formula 2)

Here, the voltage vs across the equivalent series resistance Rs is equal to the voltage drop of the inductor current il (t). Therefore, if the voltage vs (t) across the equivalent series resistance Rs and the voltage vc (t) across the capacitor CL can be made equal, the inductor current il (t) can be detected without loss by the voltage vc (t) across the capacitor CL that varies with time. That is, by satisfying equation 3, the inductor current il (t) can be detected without loss by the voltage vc (t) across the capacitor CL.

vs (t) ═ vc (t) - (formula 3)

When (formula 1) and (formula 2) are substituted into (formula 3), the following formula can be obtained.

Rs/L1/(CL. RL) - (formula 4)

Therefore, by setting the capacitance of the capacitor CL and the resistance value of the resistance RL, that is, the time constant (CR time constant) of the CR circuit including the capacitor CL and the resistance RL to satisfy (equation 4) with respect to the inductance of the inductor L and the resistance value of the equivalent series resistance Rs of the inductor L, the inductor current il (t) varying with time can be detected without loss.

(feedback Signal generating section 50)

As shown in fig. 1, the feedback signal generating unit 50 includes a terminal 501, a terminal 502, a terminal 503, and a terminal 504. Terminal 501 is connected to output terminal Pout, that is, to a parallel connection portion of the output terminal of power conversion unit 31, the output terminal of power conversion unit 32, the output terminal of power conversion unit 33, and the output terminal of power conversion unit 34. Terminal 502 is connected to a connection point of resistor RL and capacitor CL. The terminal 503 is connected to the driver 40 of the PWM control IC 400.

The terminal 504 is connected in parallel with the terminal 504 of the feedback signal generating unit 50 of another power conversion unit. That is, terminal 504 of each feedback signal generation unit 50 of power conversion unit 31, power conversion unit 32, power conversion unit 33, and power conversion unit 34 is connected to common node 540. The common node 540 is connected to the MPU 20.

The feedback signal generating unit 50 functionally has the following configuration. Fig. 3 is a circuit diagram of feedback signal generating unit 50 according to embodiment 1. As shown in fig. 3, the feedback signal generating unit 50 includes an individual current signal generating unit 52, a common signal generating unit 53, an individual current feedback signal generating unit 54, and an individual voltage feedback signal generating unit 500.

(Individual current signal generating section 52)

As shown in fig. 3, the individual current signal generating unit 52 includes an amplifier U51, a resistor R51, a resistor R52, a resistor R53, and a resistor R54.

The inverting input terminal of the amplifier U51 is connected to the terminal 501 via a resistor R51. The non-inverting input terminal of the amplifier U51 is connected to the terminal 502 via a resistor R52. The resistance value of the resistor R51 is the same as the resistance value of the resistor R52. The resistor R53 is connected between the non-inverting input terminal and the ground reference potential. The output terminal of the amplifier U51 is connected to the inverting input terminal of the amplifier U51 via a resistor R54. The resistance value of the resistor R53 is the same as the resistance value of the resistor R54. The amplifier U51 is supplied with the driving power supply VDD. With this circuit configuration, the individual current signal generating section 52 realizes a differential amplifier circuit.

The terminal 501 is connected to the output terminal Pout, and the terminal 502 is connected to a connection point between the capacitor CL and the resistor RL. Thereby, a potential difference corresponding to the inductor current iL is generated between the non-inverting input terminal and the inverting input terminal of the amplifier U51. Then, the signal based on the inductor current iL is amplified at a given amplification factor and is output as an individual current signal from the output terminal of the amplifier U51, that is, the output terminal of the individual current signal generating section 52.

(common Signal generating section 53)

As shown in fig. 3, the common signal generator 53 includes an amplifier U52 and a diode D52. The non-inverting input terminal of the amplifier U52 is connected to the output terminal of the amplifier U51. The output terminal of the amplifier U52 is connected to the inverting input terminal of the amplifier U52 via a diode D52. At this time, the anode of the diode D52 is connected to the output terminal, and the cathode of the diode D52 is connected to the inverting input terminal. The inverting input terminal is connected to terminal 504, i.e., to common node 540. The amplifier U52 is supplied with the driving power supply VDD.

With this circuit configuration, the common signal generating unit 53 realizes a maximum value holding circuit for the individual current signals for the plurality of power conversion units 31 to 34. The signal containing the maximum value of the individual current signal corresponds to the "common bus signal" of the present invention. Then, the "common bus signal" becomes the "operation number signal Sop".

(Individual current feedback signal generating section 54)

The individual current feedback signal generating unit 54 includes an amplifier U53, an amplifier U54, a transistor Tr55, a resistor R55, a resistor R56, a resistor R57, a resistor R58, a resistor R551, and a resistor R552.

The inverting input terminal of the amplifier U53 is connected to the output terminal of the amplifier U51 via a resistor R55. The non-inverting input terminal of the amplifier U53 is connected to the cathode of the diode D52 and the terminal 504 via the resistor R56. The resistance value of the resistor R55 is the same as the resistance value of the resistor R56. The resistor R57 is connected between the non-inverting input terminal of the amplifier U53 and the ground reference potential. The output terminal of the amplifier U53 is connected to the inverting input terminal of the amplifier U53 via a resistor R58. The resistance value of the resistor R57 is the same as the resistance value of the resistor R58. The amplifier U53 is supplied with the driving power supply VDD.

The non-inverting input terminal of the amplifier U54 is connected to the output terminal of the amplifier U53. An output terminal of the amplifier U54 is connected to a base of an NPN-type transistor Tr 55. The collector of the transistor Tr55 is connected to the terminal 501 via the resistor R551. The emitter of the transistor Tr55 is connected to the ground reference potential via a resistor R552. Further, the emitter of the transistor Tr55 is connected to the inverting input terminal of the amplifier U54. Further, a connection point between the collector of the transistor Tr55 and the resistor R551 is connected to the ground reference potential via a series circuit of the resistor R11 and the resistor R12.

A connection point between the resistor R11 and the resistor R12 is connected to the terminal 503. The individual voltage feedback signal generating unit 500 is configured by a series circuit of the resistor R11 and the resistor R12.

The individual current signal is input to the inverting input terminal of the amplifier U53, and the common bus signal is input to the non-inverting input terminal. As a result, a potential difference between the common bus signal and the individual current signal is generated between the non-inverting input terminal and the inverting input terminal of the amplifier U51. Also, a signal based on the potential difference of the common bus signal and the individual current signal is amplified at a given amplification ratio and output from the output terminal of the amplifier U53, that is, the terminal 503, to the amplifier U54.

The voltage-current conversion circuit is realized by a circuit including the amplifier U54, the transistor Tr55, and the resistor R552. Specifically, in this circuit, when a differential signal (differential voltage) is applied to the non-inverting input terminal of the amplifier U54, the differential signal (differential current Iadj) flows between the collector and the emitter of the transistor Tr 55. The differential current corresponds to a single current feedback signal.

When the differential current Iadj flows, the voltage at the connection point between the resistor R551 and the resistor R11 (the collector of the transistor Tr 55) becomes Vout- (Rr551 × Iadj). Rr551 is the resistance value of the resistor R551.

As a result, a voltage obtained by dividing the voltage of Vout- (Rr551 × Iadj) by the resistor R11 and the resistor R12 is output to the terminal 503. That is, a voltage corresponding to the difference between the individual current amplification signal and the operation number signal Sop (maximum value holding signal) and the output voltage Vout is output to the terminal 503. In other words, the individual current feedback signal and the individual voltage feedback signal determined by the resistance values of the resistor R551, the resistor R11, and the resistor R12 and the output voltage Vout are synthesized and output to the terminal 503 as the individual feedback signal. The individual feedback signals are fed back to the driving part 40. The driver 40 performs PWM control based on the individual feedback signal, and outputs a switching control signal to the switching element Q1 and the switching element Q2.

This can stabilize the output voltage. As described above, the feedback signal generating unit 50 is formed of an analog electronic circuit. Therefore, the feedback signal generating unit 50 can output the individual current feedback signal and the individual voltage feedback signal that respond to the fluctuation of the output voltage at high speed. Therefore, the switching power supply device 10 can achieve stabilization of the output voltage and high-speed response to fluctuations.

Therefore, the switching power supply device 10 can achieve both the digital control for performing the common arithmetic control for collectively controlling the overall operation of the plurality of power conversion units and the analog control for realizing the high-speed load response of the output voltage, and can achieve the high efficiency, the miniaturization, and the low noise of the system switching power supply device including the plurality of power conversion units.

Further, as described above, by using the digital electronic circuit for the common operation control and the analog electronic circuit for the individual power conversion units, the debugging of the system switching power supply device corresponding to various supply currents can be accommodated only by changing the number of the power conversion units in hardware and changing the firmware of the common operation control in software, and a scalable system switching power supply device having scalability capable of flexibly coping with the specification of the supply current can be realized.

Further, the switching power supply device 10 performs PWM control using the individual feedback signal in the individual power conversion unit 31, the power conversion unit 32, the power conversion unit 33, and the power conversion unit 34. This enables the switching power supply device 10 to obtain more accurate and stable output characteristics.

(configuration relating to switching control of operation count)

As described above, the operation number signal Sop as the common bus signal is input to the MPU 20. The MPU20 determines the number of operating power conversion units using the operation number signal Sop, and generates a control signal. As described above, the MPU20 is a programmable Micro Processing Unit (Micro Processing Unit), and implements the functions shown in fig. 4. That is, the MPU20 implements the functions shown in fig. 4 by digital electronic circuits.

Fig. 4 is a functional block diagram of the MPU20 according to embodiment 1. As shown in fig. 4, the MPU20 includes an ADC21, a load current calculation unit 22, an operation control signal generation unit 23, and a storage unit 24.

The storage unit 24 stores the number of operations, the operation state, and the switching threshold. That is, the MPU20 holds the operation number, the operation state, and the switching threshold. The number of operation n is the number of power conversion units currently in operation. The operation state includes a phase of a control signal (oscillation signal) supplied to the power conversion unit in operation, and for example, includes a phase or a phase difference of a control signal (oscillation signal) output to each of the power conversion units when the plurality of power conversion units are in operation. The switching threshold is a load current value that becomes a criterion for determining switching of the operation number.

The ADC21 is an analog-to-digital conversion circuit that converts the operation number signal Sop composed of an analog signal into a digital signal.

The load current calculation unit 22 calculates a load current value from the operation number signal Sop. Specifically, the load current calculation unit 22 reads the operation number n from the storage unit 24. The load current calculation unit 22 multiplies the operation number signal Sop by the operation number n to calculate a load current value Iz. The load current calculation unit 22 outputs the load current value Iz to the operation control signal generation unit 23.

The operation control signal generation unit 23 reads the switching threshold TH from the storage unit 24. The operation control signal generator 23 compares the load current value Iz with the switching threshold TH, and determines the operation number n based on the comparison result.

Specifically, the operation control signal generation unit 23 determines the operation number n based on the following principle.

Fig. 5 is a diagram for explaining a concept of switching of the operation numbers. Fig. 5 is a graph showing a relationship between an output voltage and an output current in a circuit configuration in which a plurality of power conversion units are connected in parallel. The horizontal axis represents the output current, and the vertical axis represents the output voltage.

Let n be the number of operations of the power conversion units connected in parallel, r be the resistance of the power conversion units, Vin be the input voltage, and the output voltage Vout and the output current Iout have the relationship of expression 5.

Vout ═ Vin- (r/n) Iout- (formula 5)

The input voltage Vin is constant. From this relationship, the output characteristic shown by the dotted line shown in fig. 5 can be obtained. As shown by the dotted lines, as the number of operations n increases, a larger output current Iout can be obtained while suppressing the drop amount of the output voltage Vout. That is, as the number of operations n increases, a larger load current can be obtained with a low loss for a stable desired output voltage Vout.

Here, for example, as shown in fig. 5, the input voltage Vin is set to 1.85[ V ], and the lowest value of the output voltage is set to 1.80[ V ].

The operation control signal generation unit 23 sets an output current (load current) Iout when the output characteristic per operation number n reaches 1.80V as a threshold value for switching. For example, in the example of fig. 4, the switching threshold TH12 when the operation number n is switched from 1 to 2 is set based on the output current Iout at which the output voltage Vout reaches 1.80[ V ] in the output characteristic in which the operation number n is 1. Similarly, the switching threshold TH23 for switching the operation number n from 2 to 3 is set based on the output current Iout at which the output voltage Vout reaches 1.80[ V ] in the output characteristic in which the operation number n is 2. The switching threshold TH34 for switching the operation number n from 3 to 4 is set based on the output current Iout at which the output voltage Vout reaches 1.80[ V ] in the output characteristic in which the operation number n is 3.

When the number of operations n is "1", if the load current value Iz is larger than the switching threshold TH12, the operation control signal generating unit 23 switches the number of operations n to "2". Similarly, when the number of operations n is "2", if the load current value Iz is greater than the switching threshold TH23, the operation control signal generator 23 switches the number of operations n to "3". Similarly, when the number of operations n is "3", if the load current value Iz is greater than the switching threshold TH23, the operation control signal generator 23 switches the number of operations n to "4". For example, if the load current abruptly changes and the load current value Iz becomes larger than the switching threshold TH23 when the operation number n is "1", the operation control signal generation unit 23 can also switch the operation number n from "1" to "3".

The switching threshold value when the number of operation n is decreased and the switching principle of the number of operation n can be realized by using the same principle as the above-described principle when the number of operation n is increased.

When the number of operations n is determined, the operation control signal generation unit 23 sets the power conversion unit to be operated according to the number of operations n. At this time, for example, the operation control signal generation unit 23 reads out the operation state from the storage unit 24, and sets the power conversion unit for operation with reference thereto.

As a specific example, it is assumed that the operation number n is changed to "2" when one of the power conversion units 31 is in operation and three of the other power conversion units 32, 33, and 34 are in a stop (non-operation). The operation control signal generation unit 23 reads that the power conversion unit 31 is in an operating state from the operating state, and sets any one of the power conversion unit 32, the power conversion unit 33, and the power conversion unit 34 that is not in the operating state to be operated. That is, the operation of any one of the power conversion unit 32, the power conversion unit 33, and the power conversion unit 34 which is not in the operation state is started without stopping the power conversion unit 31 in the current operation and continuing the operation.

The operation control signal generator 23 generates a control signal including the oscillation signal, and outputs the control signal to each of the power conversion units that are operated after the operation number n is switched. At this time, the operation control signal generator 23 determines the phase difference of each oscillation signal according to the operation number n.

As described above, by using the configuration of the present embodiment, the switching power supply device 10 can appropriately change the operation number n in accordance with the load current value Iz while measuring the load current value Iz (output current Iout). Thus, the switching power supply device 10 can automatically perform control so that a desired output current Iout can be output while maintaining a stable output voltage Vout.

At this time, the MPU20, which is a digital electronic circuit, determines the number of operation n and controls switching. Therefore, the configuration of the circuit for performing the determination of the number of operating rotations n and the control of switching can be simplified as compared with the case of using an analog electronic circuit. In particular, the greater the number of power conversion units, the greater the simplification effect.

In the above description, the MPU20 is divided into a plurality of functional blocks and processed. However, by performing the processing shown in fig. 6 using an arithmetic device that performs digital processing, the same processing as the MPU20 can be performed.

Fig. 6 is a flowchart showing the switching process of the operation number. The specific contents of the respective processes have been described above, and detailed description thereof is omitted. Fig. 6 is a flowchart of a process for increasing the number of operations.

As shown in fig. 6, the arithmetic device acquires the operation number signal Sop (S11). The arithmetic device reads out the held operation number n (S12).

The arithmetic device calculates a load current value Iz using the operation number signal Sop and the operation number n (S13). If the load current value IZ is larger than the switching threshold TH (S14: YES), the arithmetic device switches so that the number of operation n increases (S15). The arithmetic device changes the control signal according to the number n of operations after the switching (S16).

If the load current value IZ is equal to or less than the switching threshold TH (S14: NO), the arithmetic unit continues the original number of operations n and the control signal is continuously outputted as it is.

In addition, as for the process of reducing the number of operation n, for example, if the load current value Iz is smaller than the switching threshold TH, it can be realized by performing the process of switching so as to reduce the number of operation n or the like.

(embodiment 2)

A switching power supply device according to embodiment 2 of the present invention will be described with reference to the drawings. Fig. 7 is a circuit block diagram of switching power supply device 10A according to embodiment 2.

As shown in fig. 7, a switching power supply device 10A according to embodiment 2 is different from the switching power supply device 10 according to embodiment 1 in the configuration of an MPU20A and a feedback signal generation unit 50A. The other configurations of the switching power supply device 10A are the same as those of the switching power supply device 10, and descriptions of the same parts are omitted.

The switching power supply device 10A includes an MPU20A, a power conversion unit 31, a power conversion unit 32, a power conversion unit 33, and a power conversion unit 34. Each of power conversion unit 31, power conversion unit 32, power conversion unit 33, and power conversion unit 34 includes feedback signal generation unit 50A.

Fig. 8 is a circuit diagram of the feedback signal generating unit according to embodiment 2. As shown in fig. 8, the feedback signal generating unit 50A is different from the feedback signal generating unit 50 according to embodiment 1 in that a terminal 505 is added. The other configuration of the feedback signal generating unit 50A is the same as that of the feedback signal generating unit 50, and the description of the same parts is omitted.

Terminal 505 is connected to the output terminal of amplifier U51. Thereby, the individual current signal CSO is output from the terminal 505. Specifically, terminal 505 of feedback signal generating unit 50A of power converting unit 31 outputs individual current signal CSO1 in accordance with the operating state of power converting unit 31. Terminal 505 of feedback signal generating unit 50A of power converting unit 32 outputs individual current signal CSO2 corresponding to the operating state of power converting unit 32. Terminal 505 of feedback signal generating unit 50A of power converter 33 outputs individual current signal CSO3 in accordance with the operating state of power converter 33. Terminal 505 of feedback signal generating unit 50A of power converter 34 outputs individual current signal CSO4 according to the operating state of power converter 34.

The power conversion unit 31 outputs the individual current signal CSO1 to the MPU 20A. The power conversion unit 32 outputs the individual current signal CSO2 to the MPU 20A. The power conversion unit 33 outputs the individual current signal CSO3 to the MPU 20A. The power conversion unit 34 outputs the individual current signal CSO4 to the MPU 20A.

Fig. 9 is a functional block diagram of the MPU20A according to embodiment 2. As shown in fig. 9, the MPU20A includes an ADC261, an ADC262, an ADC263, an ADC264, a comparator 271, a comparator 272, a comparator 273, a comparator 274, and a current balance determination unit 28, compared to the MPU20 according to embodiment 1.

The ADC261, the ADC262, the ADC263, and the ADC264 are analog-to-digital conversion circuits. The ADC261 converts the individual current signal CSO1 of the analog signal into a digital signal. The ADC262 converts the individual current signal CSO2 of the analog signal into a digital signal. The ADC263 converts the individual current signal CSO3 of the analog signal into a digital signal. The ADC264 converts the individual current signal CSO4 of the analog signal into a digital signal.

The comparator 271 compares the individual current signal CSO1 and the operation number signal Sop, and outputs a comparison result. The comparator 272 compares the individual current signal CSO2 and the operation number signal Sop, and outputs a comparison result. The comparator 273 compares the individual current signal CSO3 with the operation number signal Sop, and outputs the comparison result. The comparator 274 compares the individual current signal CSO4 and the operation number signal Sop, and outputs the comparison result.

As described above, the run number signal Sop is a signal that takes the maximum value of the individual current signal. Therefore, by this processing, the comparator 271, the comparator 272, the comparator 273, and the comparator 274 can obtain the deviation of the individual current signals among the power conversion unit 31, the power conversion unit 32, the power conversion unit 33, and the power conversion unit 34.

The current balance determination unit 28 determines the balance of the individual current signals among the power conversion unit 31, the power conversion unit 32, the power conversion unit 33, and the power conversion unit 34 based on the comparison results of the comparator 271, the comparator 272, the comparator 273, and the comparator 274. At this time, the current balance determination unit 28 reads the operating state from the storage unit 24, and determines the balance using only the comparison result for the power conversion unit in operation.

For example, if the comparison result of the comparator 271 is greatly different from the comparison results of the other comparators 272, 273, and 274, the current balance determination unit 28 determines that the individual current signals among the power conversion unit 31, the power conversion unit 32, the power conversion unit 33, and the power conversion unit 34 are out of balance. The current balance determination unit 28 determines that there is a possibility of an abnormality in the operation of the power conversion unit 31, for example. The current balance determination unit 28 generates and outputs, for example, an alarm signal based on the determination result.

With this configuration, the switching power supply device 10A can obtain the same operational effects as the switching power supply device 10 and can determine the operating states of the plurality of power conversion units during operation.

Further, in this configuration, the switching power supply device 10A constitutes a circuit for determining the balance of the individual current signals by a digital electronic circuit. Therefore, the switching power supply device 10A can be realized with a simple circuit configuration including a function of determining the output balance of the plurality of power conversion units 31 to 34.

(embodiment 3)

A switching power supply device according to embodiment 3 of the present invention will be described with reference to the drawings. Fig. 10 is a circuit block diagram of a switching power supply device 10B according to embodiment 3.

As shown in fig. 10, a switching power supply device 10B according to embodiment 3 is different from the switching power supply device 10 according to embodiment 1 in that it includes a voltage dividing circuit 60. The other configurations of the switching power supply device 10B are the same as those of the switching power supply device 10, and descriptions of the same parts are omitted.

The voltage divider circuit 60 is connected between the common node 540 and the MPU 20. The voltage divider circuit 60 includes a resistor R61 and a resistor R62. The resistor R61 and the resistor R62 are connected in series, and the series circuit is connected between the common node 540 and the ground reference potential. A connection point (voltage dividing point) between the resistor R61 and the resistor R62 is connected to the MPU 20.

The voltage divider circuit 60 divides the operation number signal Sop and outputs the divided operation number signal Sop to the MPU 20.

With this configuration, the voltage of the operation number signal Sop when input to the MPU20 can be reduced. Therefore, the voltage of the operation count signal Sop can be prevented from exceeding the power supply voltage of the MPU 20. This can reliably realize the operation of the MPU20 described above. Further, the MPU20 can be reduced in voltage.

(embodiment 4)

A switching power supply device according to embodiment 4 of the present invention will be described with reference to the drawings. Fig. 11 is a circuit block diagram of a feedback signal generating unit 50R of the switching power supply device according to embodiment 4.

As shown in fig. 11, a feedback signal generating unit 50R of the switching power supply device according to embodiment 4 is different from the feedback signal generating unit 50 of the switching power supply device 10 according to embodiment 1 in that a common signal generating unit 53R is used. The other configurations of the feedback signal generating unit 50R are the same as those of the feedback signal generating unit 50, and descriptions of the same parts are omitted.

The common signal generating unit 53R includes a resistor R60. The resistor R60 is connected between the output terminal and the inverting input terminal of the amplifier U52. With this configuration, an average value calculation circuit including the amplifier U52 and the resistor R60 can be realized.

The common signal generation unit 53R outputs the average value signal as the operation number signal Sop. In this manner, even if the average value signal is used for the operation number signal Sop, the same processing as the above-described maximum value signal can be realized.

(embodiment 5)

A switching power supply device according to embodiment 5 of the present invention will be described with reference to the drawings. Fig. 12 is a circuit diagram of a circuit for detecting an inductor current of the switching power supply device according to embodiment 5.

The switching power supply device according to embodiment 5 is different from the switching power supply device 10 according to embodiment 1 in the configuration of the inductor current detection circuit. The other configurations of the switching power supply device according to embodiment 5 are the same as those of the switching power supply device 10, and descriptions of the same parts are omitted.

As shown in fig. 12, a series circuit of a resistance RL1 and a resistance RL2 is connected in parallel with the inductor L. A capacitor CL is connected in parallel to the resistor RL 2.

Even with such a configuration, the inductor current iL can be detected without loss by detecting the voltage across the capacitor CL.

The configuration of each of the above embodiments shows a mode in which the switching of the operation number is performed only with reference to the operation number signal Sop. However, it is also possible to receive a command signal from a device that switches a load to which the power supply device is connected and supplies power, and to switch the number of operating rotations with reference to the command signal.

Further, the configurations of the above-described embodiments can be appropriately combined, and the operational effects according to the respective combinations can be obtained.

Description of the reference numerals

10. 10A, 10B: a switching power supply device;

20、20A：MPU；

21、261、262、263、264：ADC；

22: a load current calculation unit;

23: an operation control signal generation unit;

24: a storage unit;

28: a current balance determination unit;

31. 32, 33, 34: a power conversion unit;

40: a drive section;

50. 50A, 50R: a feedback signal generating section;

52: an individual current signal generating section;

53. 53R: a common signal generation unit;

54: an individual current feedback signal generating section;

60: a voltage dividing circuit;

271. 272, 273, 274: a comparator;

400: a PWM control IC;

500: an individual voltage feedback signal generating section;

501. 502, 503, 504, 505: a terminal;

540: a common node;

cil, Ci2, Ci3, Ci 4: an input capacitor;

CL: a capacitor;

co 1: an output capacitor;

d52: a diode;

l: an inductor;

and (3) Pin: an input terminal;

pout: a common output terminal;

q1, Q2: a switching element;

r11, R12, R51, R52, R53, R54, R55, R56, R57, R58, R60, R61, R62, RL1, RL 2: a resistance;

rs: an equivalent series resistance;

u51, U52, U53: an amplifier;

VDD: a drive power supply;

vin: inputting a voltage;

vout: and outputting the voltage.