阅读说明：本技术 一种降压式变换电路控制器过流检测电路 (Over-current detection circuit of buck conversion circuit controller ) 是由 龚裕 袁震 于 2020-12-25 设计创作，主要内容包括：本发明公开了一种降压式变换电路控制器过流检测电路,包括第一控制开关、第二控制开关、滤波电路和比较器,第一控制开关第一端接地,第一控制开关第二端连接滤波电路输入端和第二控制开关第一端,第二控制开关第二端连接比较器第一端,比较器第二端接地,比较器第三端作为信号输出端,第一控制开关控制端用于接收控制信号,第二控制开关控制端连接可控电源端VDD,滤波电路输出端接地。本发明提供一种降压式变换电路控制器过流检测电路精度高的降压式变换电路控制器过流检测电路。(The invention discloses an overcurrent detection circuit of a buck conversion circuit controller, which comprises a first control switch, a second control switch, a filter circuit and a comparator, wherein the first end of the first control switch is grounded, the second end of the first control switch is connected with the input end of the filter circuit and the first end of the second control switch, the second end of the second control switch is connected with the first end of the comparator, the second end of the comparator is grounded, the third end of the comparator is used as a signal output end, the control end of the first control switch is used for receiving a control signal, the control end of the second control switch is connected with a controllable power supply end VDD, and the output end of the filter circuit is grounded. The invention provides an overcurrent detection circuit of a buck conversion circuit controller, which has high precision.)

1. The over-current detection circuit of the buck conversion circuit controller is characterized by comprising a first control switch, a second control switch, a filter circuit and a comparator, wherein the first end of the first control switch is grounded, the second end of the first control switch is connected with the input end of the filter circuit and the first end of the second control switch, the second end of the second control switch is connected with the first end of the comparator, the second end of the comparator is grounded, the third end of the comparator is used as a signal output end, the control end of the first control switch is used for receiving a control signal, the control end of the second control switch is connected with a controllable power supply end VDD, and the output end of the filter circuit is grounded.

2. The over-current detection circuit of the buck converter circuit controller as claimed in claim 1, wherein the second terminal of the second control switch of the second controller is further connected to a reference current source Iref.

3. The over-current detection circuit of a buck converter circuit as claimed in claim 1, wherein the first control switch is a mos transistor VT1, the source of the mos transistor VT1 is grounded, the drain of the mos transistor VT1 serves as the second terminal of the first control switch, and the gate of the mos transistor VT1 serves as the control terminal of the first control switch.

4. The over-current detection circuit of a buck converter circuit as claimed in claim 1, wherein the second control switch is a mos transistor VT2, the source of the mos transistor VT2 is the second terminal of the second control switch, the drain of the mos transistor VT2 is the first terminal of the second control switch, and the gate of the mos transistor VT2 is the control terminal of the second control switch.

5. The over-current detection circuit of a buck converter circuit controller as claimed in claim 1, wherein the filter circuit comprises an inductor L1, a resistor R1 and a capacitor C1, an input terminal of the inductor L1 is used as an input terminal of the filter circuit, an output terminal of the inductor L1 is connected to an input terminal of a resistor R1 and an input terminal of a capacitor C1, and an output terminal of the resistor R1 and an output terminal of the capacitor C1 are used as output terminals of the filter circuit.

6. The overcurrent detection circuit of the buck converter circuit controller as recited in claim 5, wherein the filter circuit comprises a variable resistor, the variable resistor comprises an insulation winding post and a conducting wire wound around the insulation winding post, two ends of the insulation winding post are respectively connected with an insulation fixing plate, a conductor slide rail is arranged between the two insulation fixing plates, a conductor slide block is arranged on the conductor slide rail, a communicating piece is arranged on the conductor slide block, the conducting wire is wrapped with an insulation skin, the conducting wire in contact with the communicating piece is not provided with an insulation skin, the communicating piece is electrically communicated with the conducting wire, the input end of the variable resistor serves as the input end of the filter circuit, the output end of the variable resistor is grounded, and the conductor slide rail is connected with the input end of the capacitor C1.

7. The buck converter circuit controller overcurrent detection circuit of claim 1, wherein the conductive lines include forward and reverse wound conductive lines, the forward wound conductive line being electrically connectable to the feedthrough.

8. The overcurrent detection circuit of the buck converter controller according to claim 1, wherein the two insulating fixing plates are further connected to an insulating guide rail, the insulating guide rail is slidably connected to an inductance control board, the inductance control board is provided with two corresponding limiting plates, and an insulating plate is further provided on one side of the inductance control board and is disposed between the two limiting plates.

9. The over-current detection circuit of a buck converter circuit controller as claimed in claim 1, wherein a conductor plate is disposed on a side of the insulating plate close to the middle of the inductive control board, the conductor plate is fixedly connected to the inductive control board, and the conductor plate is connected to the ground through a ground wire.

10. The overcurrent detecting circuit of a buck converter circuit controller as recited in claim 1, wherein the flyback conductor has a plurality of breaks, the flyback conductor at the breaks has a pair of connecting blocks, the pair of connecting blocks on the side of the inductor control board having the insulating plate are disconnected, and the pair of connecting blocks on the side of the inductor control board having no insulating plate are in contact with each other and electrically connected.

Technical Field

The invention relates to the technical field of circuit overcurrent protection, in particular to an overcurrent detection circuit of a buck conversion circuit controller.

Background

In recent years, with the rapid development of analog semiconductors, Buck controllers are widely applied in the fields of computers, electronic or electrical instruments and the like. In a Buck controller, high load current is increasingly applied, and in order to ensure that a power tube bears the short-time overload capacity, an overcurrent protection circuit is usually designed in a system.

Chinese patent publication No. CN103412180B, published 2015, 08/12/h, entitled an overcurrent detection circuit, which includes a current detection Resistor (RSENSE) for sampling the working current of a system to be detected and a voltage comparator (U2) provided with an overcurrent threshold, and is characterized in that: the over-current detection circuit further comprises a current source (IB), a voltage source (Vcc), an over-current threshold setting Resistor (RSET), a delay capacitor (COCT), a bleeder Resistor (RDIS), a first N-type MOS (metal oxide semiconductor) transistor (M2A), a second N-type MOS transistor (M2B), a third N-type MOS transistor (M2C), a fourth N-type MOS transistor (M3A), a fifth N-type MOS transistor (M3B), a first P-type MOS transistor (M1A) and a second P-type MOS transistor (M1B), wherein the second N-type MOS transistor (M2B) and the third N-type MOS transistor (M2C) respectively form a current mirror. The accuracy of this overcurrent protection is not high.

Disclosure of Invention

The invention provides the over-current detection circuit of the buck conversion circuit controller, which aims to overcome the problem that the over-current detection circuit of the buck conversion circuit controller in the prior art is low in precision.

In order to achieve the purpose, the invention adopts the following technical scheme:

the technical scheme adopted by the invention for solving the technical problems is as follows: the over-current detection circuit of the buck conversion circuit controller comprises a first control switch, a second control switch, a filter circuit and a comparator, wherein the first end of the first control switch is grounded, the second end of the first control switch is connected with the input end of the filter circuit and the first end of the second control switch, the second end of the second control switch is connected with the first end of the comparator, the second end of the comparator is grounded, the third end of the comparator is used as a signal output end, the control end of the first control switch is used for receiving a control signal, the control end of the second control switch is connected with a controllable power supply end VDD, and the output end of the filter circuit is grounded. The overcurrent detection scheme can improve the precision to 5%, and other schemes are generally about 20-30% and have low precision.

Preferably, the second terminal of the second control switch of the second controller is further connected to a reference current source Iref. The reference current source can provide a stable voltage.

Preferably, the first control switch is a mos transistor VT1, the source of the mos transistor VT1 is grounded, the drain of the mos transistor VT1 serves as the second terminal of the first control switch, and the gate of the mos transistor VT1 serves as the control terminal of the first control switch.

Preferably, the second control switch is a mos transistor VT2, the source of the mos transistor VT2 is used as the second terminal of the second control switch, the drain of the mos transistor VT2 is used as the first terminal of the second control switch, and the gate of the mos transistor VT2 is used as the control terminal of the second control switch.

Preferably, the filter circuit comprises an inductor L1, a resistor R1 and a capacitor C1, wherein an input end of the inductor L1 is used as an input end of the filter circuit, an output end of the inductor L1 is connected with an input end of a resistor R1 and an input end of a capacitor C1, and an output end of the resistor R1 and an output end of the capacitor C1 are used as output ends of the filter circuit.

Preferably, the filter circuit includes the change and feels the resistance ware, the change feels the resistance ware including insulating post of winding, the winding is at the insulating wire of winding on the post, it is insulating to wind post both ends respectively and is connected with an insulation fixed plate, be provided with the conductor slide rail between two insulation fixed plates, be provided with the conductor slider on the conductor slide rail, be provided with the connecting piece on the conductor slider, the wire outsourcing has insulating skin, wire department with the connecting piece contact does not have insulating skin, the connecting piece is here electrically communicated with the wire, change and feel the resistance ware input as the filter circuit input, change and feel resistance ware output ground connection, conductor slide rail connection electric capacity C1 input. The variable resistor can adjust the size of the inductor and the resistor, so that the filtering effect of the filter circuit is ensured, and the precision of the current detection scheme is further improved.

Preferably, the lead wire comprises a forward lead wire and a backward lead wire, and the forward lead wire can be electrically connected with the communicating piece.

Preferably, the two insulation fixing plates are further connected with insulation guide rails, the insulation guide rails are connected with inductance control boards in a sliding mode, the inductance control boards are provided with two corresponding limiting plates, one side of each inductance control board is further provided with an insulation board, and the insulation boards are arranged between the two limiting plates.

Preferably, a conductor plate is arranged on one side of the insulating plate close to the middle of the inductance control board, the conductor plate is fixedly connected with the inductance control board, and the conductor plate is connected with the ground through a grounding wire.

Preferably, a plurality of fractures are formed in the rewinding lead, a pair of connecting blocks are arranged on the rewinding lead at the fractures, the connecting blocks in pairs at the side, with the insulating plate, of the inductance control board are disconnected, and the connecting blocks in pairs at the side, without the insulating plate, of the inductance control board are mutually contacted and electrically connected. When the inductance control board slides left and right on the insulation guide rail, one part of paired connecting blocks are disconnected, one part of connecting blocks form electric connection, the limiting plate gives a pressure to the connecting blocks, the connecting blocks are connected together to play a contact effect, when the inductance control board moves left, the paired connecting blocks are separated by the conductor plates, the paired connecting blocks are respectively positioned on two sides of the conductor plates at the moment and are contacted with the conductor plates, electric connection is realized through the conductor plates, the conductor plates are grounded through wires, when the inductance control board continues to move left, the connecting blocks positioned on two sides of the conductor plates move to two sides of the insulation plates, the paired connecting blocks are disconnected, the electric connection is not performed, a magnetic field cannot be generated, the inductance strength of the whole variable inductance resistor is changed, and only one pair of connecting blocks can be simultaneously positioned on the conductor plates and.

Therefore, the invention has the following beneficial effects: (1) the overcurrent detection scheme can improve the precision to 5 percent;

(2) when the inductance control board slides left and right on the insulation guide rail, one part of the paired connecting blocks are disconnected, one part of the connecting blocks form electric connection, the limiting plate gives pressure to the connecting blocks, so that the connecting blocks are connected together to achieve a contact effect, when the inductance control board moves left, the paired connecting blocks are separated by the conductor plates, the paired connecting blocks are respectively positioned on two sides of the conductor plates and are in contact with the conductor plates, electric connection is achieved through the conductor plates, the conductor plates are grounded through the conducting wires, when the inductance control board continues to move left, the connecting blocks positioned on two sides of the conductor plates move to two sides of the insulation board, the paired connecting blocks are disconnected and are not electrically connected, a magnetic field cannot be generated, and the inductance strength of the whole variable inductance resistor is changed;

(3) the variable resistor can adjust the size of the inductor and the resistor, so that the filtering effect of the filter circuit is ensured, and the precision of the current detection scheme is further improved, the conductor sliding block is electrically connected with the conductor sliding rail, when the conductor sliding block slides on the conductor sliding rail, the communicating piece also slides on the lead at the same time, contacts different parts of the lead, and further changes the resistance value of the resistor R1;

(4) by adopting the circuit, the overcurrent protection in the Buck controller is more accurate, and the effect of protecting a chip is achieved.

Drawings

FIG. 1 is a schematic circuit diagram of the present invention

FIG. 2 is a schematic diagram of a variable resistor of the present invention

FIG. 3 is a schematic diagram of an inductor control board according to the present invention

FIG. 4 is a schematic view of a connecting block structure according to the present invention

In the figure: 2, a variable resistor, 21, an insulation winding column, 22, a reverse winding lead, 23, a forward winding lead, 24, a conductor slide rail, 25, a conductor slide block, 26, an inductance control board, 261, a limiting board, 262, a conductor board, 263, an insulating board and 27, an insulating guide rail.

Detailed Description

The invention is further described with reference to the following detailed description and accompanying drawings.

Example (b): an overcurrent detection circuit of a buck conversion circuit controller is shown in figure 1 and comprises a first control switch, a second control switch, a filter circuit and a comparator, wherein the first end of the first control switch is grounded, the second end of the first control switch is connected with the input end of the filter circuit and the first end of the second control switch, the second end of the second control switch is connected with the first end of the comparator, the second end of the comparator is grounded, the third end of the comparator is used as a signal output end, the control end of the first control switch is used for receiving a control signal, the control end of the second control switch is connected with a controllable power supply end VDD, and the output end of the filter circuit is grounded. The second end of the second control switch of the second controller is connected with a reference current source Iref. The reference current source can provide a stable voltage. The first control switch is a mos transistor VT1, the source of the mos transistor VT1 is grounded, the drain of the mos transistor VT1 is used as the second end of the first control switch, and the gate of the mos transistor VT1 is used as the control end of the first control switch. The second control switch is a mos transistor VT2, the source electrode of the mos transistor VT2 is used as the second end of the second control switch, the drain electrode of the mos transistor VT2 is used as the first end of the second control switch, and the grid electrode of the mos transistor VT2 is used as the control end of the second control switch. The filter circuit comprises an inductor L1, a resistor R1 and a capacitor C1, wherein the input end of the inductor L1 is used as the input end of the filter circuit, the output end of the inductor L1 is connected with the input end of a resistor R1 and the input end of a capacitor C1, and the output end of the resistor R1 and the output end of the capacitor C1 are used as the output end of the filter circuit.

VT1 is Buck power down tube with impedance R_vt1(ii) a VT2 is matching pipe with impedance R_vt2. When the power down tube VT1 is turned on and negative current OCP is detected, the current flows clockwise as indicated by arrow LOCP in fig. 1.

When the positive terminal of the comparator comp is grounded, i.e. the negative terminal voltage is equal to 0, the comparator flips to trigger the OCP, i.e. I_ocp*R_vt1+I_ref*R_vt2=0。

When the gate of VT1 receives the trigger signal, VT1 is turned on, the voltage of VT2 drain is pulled down, VT2 is normally turned on, so that the voltage of comp negative end is pulled down, the comparator is turned over, and OCP is triggered; the filter circuit filters signals in the circuit, the detection accuracy of the circuit is improved, and signals are continuously provided to the grid of the mos transistor VT2, so that the VT2 is always conducted.

As shown in fig. 2, the filter circuit includes the change resistance sensor 2, the change resistance sensor includes the insulation and winds post 21, the winding is at the insulation wire of post of winding, the insulation is respectively connected with an insulation fixed plate around the post both ends, be provided with conductor slide rail 24 between two insulation fixed plates, be provided with conductor slider 25 on the conductor slide rail, be provided with the communicating piece on the conductor slider, the wire outsourcing has insulating skin, wire department with the communicating piece contact does not have insulating skin, the communicating piece is here electrically communicated with the wire, change resistance sensor input as the filter circuit input, change resistance sensor output ground connection, conductor slide rail connection electric capacity C1 input. The wires include a forward winding wire 23 and a reverse winding wire 22, and the forward winding wire can be electrically connected with the communicating member. The two insulation fixing plates are further connected with an insulation guide rail 27, the insulation guide rail is connected with an inductance control board 26 in a sliding mode, as shown in fig. 3, two corresponding limiting plates 261 are arranged on the inductance control board 26, an insulation plate 263 is further arranged on one side of the inductance control board, and the insulation plate is arranged between the two limiting plates. Conductor plate 262 is set up to one side of insulation board near the inductance control board middle part, and conductor plate and inductance control board fixed connection, conductor plate pass through earth conductor and connect the earth. As shown in fig. 4, a plurality of fractures are formed in the rewinding wire, a pair of connecting blocks are arranged on the rewinding wire at the fractures, the connecting blocks in pairs on the side of the inductance control board with the insulating board are disconnected, and the connecting blocks in pairs on the side of the inductance control board without the insulating board are contacted with each other and form an electrical connection.

The reversely wound conducting wire is wound on the surface of the insulating column, the normally wound conducting wire is wound on the reversely wound conducting wire, the connecting blocks extend out of the normally wound conducting wire layer from the gap of the normally wound conducting wire, a pair of connecting blocks extend out between the two normally wound conducting wires, and the normally wound conducting wire plays a role in fixing the reversely wound conducting wire and the connecting blocks; the left side of the conductor plate is in a pointed shape, so that a pair of connecting blocks can be conveniently separated, an inclined plane can be arranged on the right side of each connecting block, the left side of the conductor plate can be conveniently inserted, and the pair of connecting blocks can be further separated; the connecting block is to protruding a curved surface in the middle, and the convenience can make the fine contact of a pair of connecting block when receiving the pressure of limiting plate like this, avoids contact failure to take place.

The overcurrent detection scheme can improve the precision to 5%, and other schemes are generally about 20-30% and have low precision.

The variable resistor can adjust the size of the inductor and the resistor, so that the filtering effect of the filter circuit is ensured, and the precision of the current detection scheme is further improved.

When the inductance control board slides left and right on the insulation guide rail, one part of paired connecting blocks are disconnected, one part of connecting blocks form electric connection, the limiting plate gives a pressure to the connecting blocks, the connecting blocks are connected together to play a contact effect, when the inductance control board moves left, the paired connecting blocks are separated by the conductor plates, the paired connecting blocks are respectively positioned on two sides of the conductor plates at the moment and are contacted with the conductor plates, electric connection is realized through the conductor plates, the conductor plates are grounded through wires, when the inductance control board continues to move left, the connecting blocks positioned on two sides of the conductor plates move to two sides of the insulation plates, the paired connecting blocks are disconnected, the electric connection is not performed, a magnetic field cannot be generated, the inductance strength of the whole variable inductance resistor is changed, and only one pair of connecting blocks can be simultaneously positioned on the conductor plates and.

I_refThe design is such that a reference current scheme can be employed to ensure its accuracy.