阅读说明：本技术 开关电源电路及其控制方法、电源芯片及相关系统 (Switching power supply circuit, control method thereof, power supply chip and related system ) 是由 顾仲跃 于 2021-08-26 设计创作，主要内容包括：本申请涉及电力电子技术领域,公开了开关电源电路及其控制方法、电源芯片及相关系统,该开关电源电路包括：自激振荡电路,自激振荡电路的输入端接收电源电压,自激振荡电路的输出端用于输出第一驱动信号。升压型开关电源电路,与自激振荡电路的输出端连接,升压型开关电源电路接收电源电压,第一驱动信号用于驱动升压型开关电源电路的开关管导通或关断,以使升压型开关电源电路输出供电电压,能够降低开关电源电路工作所需的最低电源电压。基于本申请的技术方案,有利于提高开关电源电路的适用性。(The application relates to the technical field of power electronics, and discloses a switching power supply circuit, a control method thereof, a power supply chip and a related system, wherein the switching power supply circuit comprises: and the input end of the self-excited oscillation circuit receives the power supply voltage, and the output end of the self-excited oscillation circuit is used for outputting a first driving signal. The boost type switching power supply circuit is connected with the output end of the self-oscillation circuit, receives power supply voltage, and the first driving signal is used for driving a switching tube of the boost type switching power supply circuit to be switched on or switched off so that the boost type switching power supply circuit outputs power supply voltage and can reduce the lowest power supply voltage required by the working of the switching power supply circuit. Based on the technical scheme of this application, be favorable to improving switching power supply circuit's suitability.)

1. A switching power supply circuit, comprising:

the self-oscillation circuit comprises a self-oscillation circuit, a first control circuit and a second control circuit, wherein the input end of the self-oscillation circuit receives power supply voltage, and the output end of the self-oscillation circuit is used for outputting a first driving signal;

the boost type switching power supply circuit is connected with the output end of the self-oscillation circuit, receives the power supply voltage, and the first driving signal is used for driving a switching tube of the boost type switching power supply circuit to be switched on or switched off so that the boost type switching power supply circuit outputs the power supply voltage and can reduce the lowest power supply voltage required by the working of the switching power supply circuit.

2. The switching power supply circuit according to claim 1, wherein the step-up switching power supply circuit comprises:

an inductor, one end of the inductor receiving the supply voltage;

a first diode having an anode receiving the power supply voltage;

the cathode of the first diode is connected to the other end of the inductor through the first capacitor;

the input end of the self-oscillation circuit is connected to the cathode of the first diode.

3. The switching power supply circuit according to claim 2, further comprising:

the anode of the second diode is connected with the other end of the inductor and the first end of the switching tube;

the cathode of the second diode is connected to the second end of the switch tube through the second capacitor, and the second end of the switch tube is grounded;

and the control end of the switching tube is connected with the output end of the self-oscillation circuit so as to receive the first driving signal.

4. The switching power supply circuit according to any one of claims 1 to 3, further comprising:

a negative feedback waveform generating circuit, wherein a power supply end of the negative feedback waveform generating circuit receives the power supply voltage, a negative feedback input end of the negative feedback waveform generating circuit receives the power supply voltage through at least one resistor, and an output end of the negative feedback waveform generating circuit is used for outputting a second driving signal;

the switching circuit is used for switching a signal received by the control end of the switching tube so that the control end of the switching tube receives the first driving signal or the second driving signal, and the boost switching power supply circuit can drive the switching tube to be switched on or switched off based on the first driving signal or the second driving signal, so that the minimum power supply voltage required by the working of the switching power supply circuit is reduced, and the long-term stability of the power supply voltage is ensured.

5. The switching power supply circuit according to claim 4, wherein the switching circuit comprises:

the single-pole double-throw switch comprises a first connecting end, a second connecting end and a common end, wherein the first connecting end is connected to the output end of the self-oscillation circuit, the second connecting end is connected to the output end of the negative feedback waveform generating circuit, and the common end is connected to the control end of the switch tube.

6. A switching power supply circuit according to any one of claims 1 to 3, wherein the self-oscillating circuit is a self-feedback oscillator.

7. A control method of a switching power supply circuit, characterized by being applied to the switching power supply circuit according to claim 4 or 5; the control method comprises the following steps:

controlling the switching circuit to enable the switching tube to receive the first driving signal so as to conduct or shut off;

tracking and judging whether the power supply voltage is not less than a preset voltage or not;

and if so, controlling the switching circuit to enable the switching tube to receive the second driving signal so as to conduct or shut off.

8. A power supply chip characterized by comprising the switching power supply circuit according to any one of claims 1 to 6.

9. A battery management system, characterized in that the battery management system comprises the power supply chip according to claim 8.

10. A control system, characterized in that the control system comprises the power supply chip of claim 8.

Technical Field

The present disclosure relates to the field of power electronics technologies, and in particular, to a switching power supply circuit, a control method thereof, a power supply chip, and a related system.

Background

In the prior art, a switching power supply circuit is generally used to provide a supply voltage higher than a power supply voltage and to supply an operating circuit requiring a higher input voltage based on the supply voltage.

The prior art has the defects that the switching power supply circuit can provide a power supply voltage higher than a power supply voltage only by receiving a driving signal, and the traditional negative feedback waveform generating circuit has larger required input voltage due to the fact that the traditional negative feedback waveform generating circuit is provided with an amplifier and other devices, so that the power supply voltage is at least required to be larger than the required input voltage of the negative feedback waveform generating circuit, the application scene of the switching power supply circuit is greatly limited, and the applicability of the switching power supply circuit is reduced.

Disclosure of Invention

The technical problem that this application mainly solved is how to reduce the minimum mains voltage that switching power supply circuit work required to improve switching power supply circuit's suitability.

In order to solve the above technical problem, the first technical solution adopted by the present application is: 1. a switching power supply circuit comprising: the input end of the self-excited oscillation circuit receives power supply voltage, and the output end of the self-excited oscillation circuit is used for outputting a first driving signal; the boost type switching power supply circuit is connected with the output end of the self-oscillation circuit, receives power supply voltage, and the first driving signal is used for driving a switching tube of the boost type switching power supply circuit to be switched on or switched off so that the boost type switching power supply circuit outputs power supply voltage and can reduce the lowest power supply voltage required by the working of the switching power supply circuit.

In order to solve the above technical problem, the second technical solution adopted by the present application is: a control method of a switch power supply circuit is applied to the switch power supply circuit; the control method comprises the following steps: the switching circuit is controlled to enable the switching tube to receive a first driving signal so as to conduct or shut off; tracking and judging whether the power supply voltage is not less than a preset voltage or not; if yes, the switching circuit is controlled to enable the switching tube to receive the second driving signal to conduct or cut off.

In order to solve the above technical problem, a third technical solution adopted by the present application is: a power supply chip comprises the switch power supply circuit.

In order to solve the above technical problem, a fourth technical solution adopted by the present application is: a battery management system comprises the power supply chip.

In order to solve the above technical problem, a fifth technical solution adopted by the present application is: a control system comprises the power supply chip.

The beneficial effect of this application is: different from the prior art, this application adopts self-excited oscillation circuit to provide first drive signal to utilize first drive signal drive boost type switching power supply circuit's switching tube to switch on or turn-off, so that boost type switching power supply circuit output is than the higher supply voltage of mains voltage, wherein, the required input voltage of self-excited oscillation circuit is lower than traditional negative feedback waveform generation circuit, consequently, the required minimum mains voltage of switching power supply circuit work is reduced to the technical scheme of this application, and then has improved switching power supply circuit's suitability.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings needed to be used in the description of the embodiments will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts. Wherein:

FIG. 1 is a circuit schematic of a first embodiment of a switching power supply circuit of the present application;

FIG. 2 is a circuit schematic of a second embodiment of the switching power supply circuit of the present application;

FIG. 3 is a circuit diagram of a third embodiment of the switching power supply circuit of the present application;

FIG. 4 is a circuit diagram of a fourth embodiment of the switching power supply circuit of the present application;

FIG. 5 is a schematic circuit diagram of a fifth embodiment of the switching power supply circuit of the present application;

FIG. 6 is a schematic flow chart diagram illustrating an embodiment of a control method for a switching power supply circuit according to the present application;

FIG. 7 is a schematic diagram of an embodiment of a power chip;

FIG. 8 is a schematic diagram of an embodiment of a battery management system of the present application;

FIG. 9 is a schematic block diagram of an embodiment of a control system of the present application.

Detailed Description

The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are only a part of the embodiments of the present application, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.

The terms "first" and "second" in this application are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. In the description of the present application, "plurality" means at least two, e.g., two, three, etc., unless explicitly specifically limited otherwise. Furthermore, the terms "include" and "have," as well as any variations thereof, are intended to cover non-exclusive inclusions. For example, a process, method, system, article, or apparatus that comprises a list of steps or elements is not limited to only those steps or elements listed, but may alternatively include other steps or elements not listed, or inherent to such process, method, article, or apparatus.

Fig. 1 is a circuit diagram of a first embodiment of a switching power supply circuit according to the present application.

The present application proposes a switching power supply circuit, which includes a self-oscillation circuit 101 and a step-up type switching power supply circuit 102, as shown in fig. 1.

And a self-oscillation circuit 101, an input end of the self-oscillation circuit 101 is connected with a power supply to receive a power supply voltage (such as Vin in fig. 1) to obtain power supply, and the self-oscillation circuit 101 can perform self-oscillation generation and output a first driving signal after receiving the power supply voltage.

The boost switching power supply circuit 102 is connected to a power supply to receive a power supply voltage and to obtain power supply. The boost switching power supply circuit 102 is connected to the output terminal of the self-oscillation circuit 101, and the boost switching power supply circuit 102 includes a switching tube 1021, the switching tube 1021 can receive a first driving signal output by the self-oscillation circuit 101, and the first driving signal is used to turn on or off the switching tube 1021, so that the boost switching power supply circuit 102 outputs a supply voltage (e.g. Vout in fig. 1).

The conventional negative feedback waveform generating circuit for generating the driving signal to drive the switching tube 1021 needs a larger supply voltage to operate (for example, a supply voltage of 2V is needed to operate), while the self-oscillating circuit 101 needs a smaller supply voltage to generate the first driving signal (for example, only a supply voltage of 0.8V is needed to operate), so that the self-oscillating circuit 101 is used to generate and output the first driving signal to drive the switching tube 1021 of the boost switching power circuit 102 to enable the boost switching power circuit 102 to output the supply voltage, which can reduce the minimum value of the supply voltage needed by the switching power circuit, so that the switching power circuit can be used in more application scenarios with only a lower supply voltage.

Different from the prior art, the self-excited oscillation circuit 101 is adopted to provide the first driving signal, and the first driving signal is utilized to drive the switching tube 1021 of the boost type switching power supply circuit 102 to be switched on or switched off, so that the boost type switching power supply circuit 102 outputs a supply voltage higher than a power supply voltage, wherein an input voltage required by the self-excited oscillation circuit 101 is lower than that of a traditional negative feedback waveform generation circuit, and therefore the technical scheme of the application reduces the minimum power supply voltage required by the working of the switching power supply circuit, and further improves the applicability of the switching power supply circuit.

Fig. 2 is a circuit diagram of a second embodiment of the switching power supply circuit of the present application.

Alternatively, as shown in fig. 2, the boost-type switching power supply circuit 102 may include: an inductor 1022, a first diode 1023, and a first capacitor 1024.

One end of the inductor 1022 and the positive electrode of the first diode 1023 are connected to a power supply respectively to receive a power supply voltage. A first terminal of the first capacitor 1024 is connected to the other terminal of the inductor 1022, and a second terminal of the first capacitor 1024 is connected to the cathode of the first diode 1023. An input terminal of the self-oscillation circuit 101 is connected to a cathode of the first diode 1023 and a second terminal of the first capacitor 1024 to receive a voltage of the second terminal of the first capacitor 1024.

As the switching tube 1021 is cycled between the on and off states by the driving of the first driving signal, the first terminal voltage of the first capacitor 1024 is continuously switched between the supply voltage and the ground voltage. According to the bootstrap effect of the capacitor, when the voltage of the first terminal of the first capacitor 1024 is switched from the supply voltage to the ground voltage, the voltage of the second terminal of the first capacitor 1024 also drops, and the power supply voltage is charged to the second terminal of the first capacitor 1024 through the first diode 1023. According to the bootstrap effect of the capacitor, when the voltage at the first terminal of the first capacitor 1024 is switched from the ground voltage to the power supply voltage, the voltage at the second terminal of the first capacitor 1024 will suddenly rise, but the voltage at the second terminal of the first capacitor 1024 will not drop due to the reverse blocking of the first diode 1023. Based on this operation principle, the voltage at the second end of the first capacitor 1024 will continuously rise.

The maximum amplitude of the first driving signal output by the self-oscillation circuit 101 is in positive correlation with the voltage received by the self-oscillation circuit 101, so that when the voltage of the second end of the first capacitor 1024 is increased, the maximum amplitude of the first driving signal is also increased, the on/off speed of the switching tube can be increased, and the increase speed of the power supply voltage is increased.

Further, as shown in fig. 2, the switching power supply circuit may further include: a second diode 1025 and a second capacitor 1026.

An anode of the second diode 1025 is connected to the inductor 1022 and the first end of the switch tube 1021, a cathode of the second diode 1025 is connected to the first end of the second capacitor 1026, a second end of the second capacitor 1026 is connected to the second end of the switch tube 1021, and the second end of the switch tube 1021 is grounded. The control end of the switching tube 1021 is connected with the output end of the self-oscillation circuit 101 to receive the first driving signal, and the first end of the switching tube 1021 and the second end of the switching tube 1021 are switched on or off under the driving of the first driving signal. The cathode of the second diode 1025 and the first end of the second capacitor 1026 are the output end of the boost-type switching power supply circuit 102, and are used for outputting the supply voltage.

When the switch tube 1021 is turned on, the inductor is charged based on the power supply voltage, and the current flows to the ground. When the switching tube 1021 is blocked, the second capacitor 1026 is charged based on the superimposed voltage of the inductive voltage and the power voltage, so as to increase the power supply voltage. The second diode 1025 acts as a reverse blocking preventing the supply voltage from dropping. Based on this working principle, the supply voltage will rise continuously.

Fig. 3 is a circuit diagram of a third embodiment of the switching power supply circuit of the present application.

Optionally, as shown in fig. 3, the switching power supply circuit further includes a negative feedback waveform generation circuit 103 and a switching circuit 104.

The power supply end of the negative feedback waveform generating circuit 103 receives a power supply voltage, the negative feedback input end of the negative feedback waveform generating circuit 103 receives the power supply voltage through at least one resistor, the output end of the negative feedback waveform generating circuit 103 can output a second driving signal, and the second driving signal can be used for driving the switching tube 1021 to be switched on or switched off. The at least one resistor may include a first resistor 1031, a second resistor 1032, and a third resistor 1033 in the negative feedback waveform generating circuit 103.

The switching circuit 104 is connected to the output terminal of the self-oscillation circuit 101, the output terminal of the negative feedback waveform generation circuit 103, and the control terminal of the switching tube 1021. The switching circuit 104 may connect the output terminal of the self-oscillation circuit 101 to the control terminal of the switching tube 1021 to enable the control terminal of the switching tube 1021 to receive the first driving signal, or connect the output terminal of the negative feedback waveform generating circuit 103 to the control terminal of the switching tube 1021 to enable the control terminal of the switching tube 1021 to receive the second driving signal, so that the boost switching power circuit 102 can drive the switching tube to be turned on or turned off based on the first driving signal or the second driving signal.

The negative feedback waveform generating circuit 103 can perform negative feedback adjustment on the second driving signal according to the supply voltage output by the switching power supply circuit due to the existence of negative feedback (the negative feedback input end receives the supply voltage through at least one resistor), so that the second driving signal is more stable and reliable than the first driving signal output by the self-oscillation circuit 101 without negative feedback. The user can freely select to adopt the first driving signal or the second driving signal to drive the switch tube 1021 according to the current working condition, and the applicability of the switching power supply circuit is improved.

Fig. 4 is a circuit diagram of a fourth embodiment of the switching power supply circuit of the present application.

Further, as shown in fig. 4, the switching circuit 104 may be a single-pole double-throw switch.

The single-pole double-throw switch comprises a first connecting end, a second connecting end and a common end, wherein the first connecting end is connected to the output end of the self-oscillation circuit, the second connecting end is connected to the output end of the negative feedback waveform generating circuit, and the common end is connected to the control end of the switch tube. With the switch switching of the single-pole double-throw switch, the first connecting end can be connected with the public end, and the second connecting end can also be connected with the public end.

Specifically, the switching circuit 104 may also be other circuits or devices having the above-mentioned function of switching the connection line, and is not limited herein.

Fig. 5 is a circuit diagram of a fifth embodiment of the switching power supply circuit of the present application.

Further, as shown in fig. 5, the negative feedback waveform generating circuit 103 further includes: an error amplifier 1034 and a duty cycle analog-to-digital conversion module 1035.

A first input terminal of the error amplifier 1034 receives a reference voltage (e.g., Vref in fig. 5) generated by the reference voltage generation circuit, and a second input terminal of the error amplifier 1034 receives a supply voltage through at least one resistor (e.g., a first resistor 1031, a second resistor 1032, and a third resistor 1033). An input terminal of the duty analog-to-digital conversion module 1035 is connected to the output terminal of the error amplifier 1034, an output terminal of the duty analog-to-digital conversion module 1035 is connected to the switching circuit 104, and an output terminal of the duty analog-to-digital conversion module 1035 is used to output the second driving signal.

Alternatively, the self-oscillation circuit 101 may be a self-feedback oscillator or other circuit or device with self-oscillation function, and is not limited herein.

Note that the negative feedback waveform generation circuit 103 (the error amplifier 1034 and the duty ratio analog-to-digital conversion module 1035) is powered by the higher of the power supply voltage and the power supply voltage.

Fig. 6 is a flowchart illustrating an embodiment of a control method of a switching power supply circuit according to the present application.

The present application further provides a control method of a switching power supply circuit, which is applied to the switching power supply circuit according to any one of the embodiments shown in fig. 3 to 5.

As shown in fig. 6, the control method includes:

step S1: the switching circuit 104 is controlled to make the switch tube 1021 receive the first driving signal to conduct or switch off.

Step S2: and tracking and judging whether the power supply voltage is not less than a preset voltage.

When the determination result of the step S2 is yes (when the power supply voltage is not less than the preset voltage), a step S3 is performed. Step S3: the switching circuit 104 is controlled to make the switch tube 1021 receive the second driving signal to conduct or switch off.

As mentioned above, the second driving signal outputted from the negative feedback waveform generating circuit 103 is more stable and reliable than the first driving signal outputted from the self-oscillation circuit 101 without negative feedback, but the negative feedback waveform generating circuit 103 needs a larger voltage than the self-oscillation circuit 101 to supply power, and if the power supply voltage is smaller, the negative feedback waveform generating circuit 103 cannot be initially supplied with power based on the power supply voltage to output the second driving signal.

In the control method adopted in the present embodiment, the predetermined voltage is a voltage sufficient to power the negative feedback waveform generation circuit 103, and the power supply terminal of the negative feedback waveform generation circuit receives the power supply voltage. When the power supply voltage is less than the preset voltage (i.e. when the switching power supply circuit is just started), the self-oscillation circuit 101 (powered by the lower power supply voltage) may be used to output a first driving signal to drive the switching tube 1021. When the power supply voltage is not less than the predetermined voltage (i.e. the switching power supply circuit operates for a period of time and the power supply voltage has been raised to a certain extent), the negative feedback waveform generating circuit 103 (powered by the power supply voltage) may be used to output the second driving signal to drive the switching tube 1021. Based on the working principle, the self-oscillation circuit 101 can be started by a lower power supply voltage to drive the switch tube 1021, so that the power supply voltage is initially raised. When the power supply voltage is not less than the preset voltage, the negative feedback waveform generating circuit 103 is started based on the power supply voltage to provide a more stable second driving signal to drive the switching tube 1021, thereby ensuring the long-term stability of the power supply voltage.

Different from the prior art, the control method adopted by the application can drive the switching power supply circuit based on the extremely low power supply voltage so as to improve the power supply voltage, and when the power supply voltage is greater than the preset voltage, the second driving signal generated by the negative feedback waveform generating circuit 103 with negative feedback is adopted to drive the switching power supply circuit so as to improve the long-term stability of the power supply voltage.

Fig. 7 is a schematic structural diagram of an embodiment of a power chip of the present application.

The present application also proposes a power supply chip, as shown in fig. 7, the power supply chip 70 at least includes a switching power supply circuit 71, and the switching power supply circuit 71 is used for starting the working circuit. The switching power supply circuit 71 is the switching power supply circuit disclosed in the above embodiments, and is not described herein again.

Different from the prior art, the self-excited oscillation circuit 101 is adopted to provide the first driving signal, and the first driving signal is utilized to drive the switching tube 1021 of the boost type switching power supply circuit 102 to be switched on or switched off, so that the boost type switching power supply circuit 102 outputs a supply voltage higher than a power supply voltage, wherein an input voltage required by the self-excited oscillation circuit 101 is lower than that of a traditional negative feedback waveform generation circuit, and therefore the technical scheme of the application reduces the minimum power supply voltage required by the working of the switching power supply circuit, and further improves the applicability of the switching power supply circuit.

Fig. 8 is a schematic structural diagram of an embodiment of the battery management system of the present application.

The present application also proposes a battery management system, as shown in fig. 8, the battery management system 80 includes a power supply chip 70. The power chip 70 is the power chip disclosed in the above embodiments, and is not described herein.

Specifically, the battery management system 80 may be a device battery management system, an automobile battery management system, or other types of battery management systems, which is not limited herein.

Different from the prior art, the self-excited oscillation circuit 101 is adopted to provide the first driving signal, and the first driving signal is utilized to drive the switching tube 1021 of the boost type switching power supply circuit 102 to be switched on or switched off, so that the boost type switching power supply circuit 102 outputs a supply voltage higher than a power supply voltage, wherein an input voltage required by the self-excited oscillation circuit 101 is lower than that of a traditional negative feedback waveform generation circuit, and therefore the technical scheme of the application reduces the minimum power supply voltage required by the working of the switching power supply circuit, and further improves the applicability of the switching power supply circuit.

FIG. 9 is a schematic block diagram of an embodiment of a control system of the present application.

The present application also proposes a control system, as shown in fig. 9, the control system 90 includes a power supply chip 70. The power chip 70 is the power chip disclosed in the above embodiments, and is not described herein.

Specifically, the control system 90 may be a power control system, a communication control system, or other types of control systems, which are not limited herein.

Different from the prior art, the self-excited oscillation circuit 101 is adopted to provide the first driving signal, and the first driving signal is utilized to drive the switching tube 1021 of the boost type switching power supply circuit 102 to be switched on or switched off, so that the boost type switching power supply circuit 102 outputs a supply voltage higher than a power supply voltage, wherein an input voltage required by the self-excited oscillation circuit 101 is lower than that of a traditional negative feedback waveform generation circuit, and therefore the technical scheme of the application reduces the minimum power supply voltage required by the working of the switching power supply circuit, and further improves the applicability of the switching power supply circuit.

The above description is only for the purpose of illustrating embodiments of the present application and is not intended to limit the scope of the present application, and all modifications of equivalent structures and equivalent processes, which are made by the contents of the specification and the drawings of the present application or are directly or indirectly applied to other related technical fields, are also included in the scope of the present application.