Negative voltage driving circuit

Abstract

The utility model relates to a negative voltage driving circuit, which belongs to the technical field of power electronics, and comprises a driving module, the input end of which is connected with a single-chip microcomputer control signal; the input end of the charging module is connected with the output end of the driving module, and the output end of the charging module outputs negative driving voltage; the control end of the negative voltage starting module is connected with the output end of the charging module, the input end of the negative voltage starting module is connected with the transformer, and the output end of the negative voltage starting module is connected with the grounding end. According to the invention, negative voltage output does not need to be additionally increased, and the complexity and cost of the circuit are reduced while the negative voltage driving function of the circuit is realized.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of power electronics, and particularly relates to a negative voltage driving circuit. BACKGROUND

[0002] At present, semiconductor field effect transistors are widely used in high-voltage and high-frequency power electronic devices, especially in switching power supplies, power converters and inverters.

[0003] Since the semiconductor field effect transistor needs to provide a negative voltage driving in the driving signal when being turned off to ensure the reliable turn-off of the switching tube. The cost of the commonly used professional driver is high, and an additional negative voltage output needs to be added in the auxiliary power supply design, which increases the complexity and cost of the circuit. CONTENT OF THE INVENTION

[0004] The present application provides a negative voltage driving circuit, which can not need to additionally add a negative voltage output, realizes the negative voltage driving function of the circuit, and reduces the complexity and cost of the circuit.

[0005] A negative voltage driving circuit comprises:

[0006] A driving module, an input end of the driving module being connected with a single-chip microcomputer control signal;

[0007] A charging module, an input end of the charging module being connected with an output end of the driving module, and an output end of the charging module outputting a negative driving voltage;

[0008] A negative voltage starting module, a control end of the negative voltage starting module being connected with an output end of the charging module, an input end of the negative voltage starting module being connected with a transformer, and an output end of the negative voltage starting module being connected with a ground end.

[0009] By adopting the above technical scheme, when the single-chip microcomputer pulls down the input level of the negative voltage driving circuit, the driving module, the charging module and the negative voltage starting module form a negative voltage driving loop, the charging module provides the negative driving voltage to the control end of the negative voltage starting module, so that an additional negative voltage circuit through the auxiliary power supply transformer does not need to be designed, the negative voltage driving function of the circuit is realized through a simple circuit, and the cost of the circuit can be reduced.

[0010] Optionally, a rectifying module is further included, the rectifying module being used for rectifying the voltage output by the transformer, an input end of the rectifying module being connected with an output end of the transformer, and an output end of the rectifying module being used for outputting a rectified voltage.

[0011] By adopting the technical scheme, the alternating voltage can be converted into direct current voltage through rectification of the transformer output voltage, so that a stable direct current power supply is provided for the negative voltage driving circuit, and circuit performance fluctuation or damage caused by unstable power supply is avoided.

[0012] Optionally, the driving module comprises a first transistor Q1, a second transistor Q2 and a first capacitor C1, the first transistor Q1 is an NPN type transistor, and the second transistor Q2 is a PNP type transistor.

[0013] The base of the first transistor Q1 and the second transistor Q2 is connected with the input end of the driving module, the collector of the first transistor Q1 is connected with the driving voltage and the first capacitor C1 respectively, one end of the first capacitor C1 is connected with the ground end, and the collector of the second transistor Q2 is connected with the ground end.

[0014] The emitter of the first transistor Q1 and the second transistor Q2 is connected with the output end of the driving module.

[0015] By adopting the technical scheme, the parameters of the first transistor Q1 and the second transistor Q2 are inconsistent, that is, in the first transistor Q1 and the second transistor Q2, any one of the transistors is turned on and the other transistor is turned off. Assuming that the level signal of the single-chip microcomputer control signal is low, the first transistor Q1 is turned off and the second transistor Q2 is turned on, when the second transistor Q2 is turned on, the driving module forms the ground end; assuming that the level signal of the single-chip microcomputer control signal is high, the first transistor Q1 is turned on and the second transistor Q2 is turned off, when the first transistor Q1 is turned on, the driving voltage of 12V can be output to the charging module through the first transistor Q1.

[0016] Optionally, the charging module comprises a first resistor R1, a second resistor R2, a first diode D1, a second capacitor C2 and a second diode D2.

[0017] The first resistor R1, the second resistor R2 and one end of the first diode D1 are connected with the input end of the charging module, the other end of the first resistor R1, the second resistor R2 and the first diode D1 are connected with the second diode D2, and the connection position of the second resistor R2 and the second diode D2 is connected with the second capacitor C2.

[0018] The connection position of the second capacitor C2 and the second diode D2 is connected with the output end of the charging module.

[0019] By adopting the technical scheme, the first resistor R1 and the second resistor R2 constitute a voltage division network, when the first triode Q1 in the driving module is turned on, the driving voltage of 12V supplies power for the second capacitor C2, and the second capacitor C2 stores energy; when the first triode Q1 is turned off, the second capacitor C2 releases voltage to supply power, and the second capacitor C2, the second diode D2, the first diode D1 and the second triode Q2 form a grounding loop, and the second capacitor C2 is charged through the second capacitor C2; when the second triode Q2 is turned on after the second capacitor C2 is fully charged, the negative driving voltage can be provided for the negative voltage starting module 3; and the second diode D2 can prevent the third capacitor C3 from discharging to the ground. When the control signal SW1 output by the single-chip microcomputer is at a low level, the second triode Q2 in the driving module is turned on, the second capacitor C2 is discharged, and finally a negative driving voltage is output at the output end of the charging module.

[0020] Optionally, the negative voltage starting module comprises a third resistor R3 and a MOS tube Q3.

[0021] The drain of the MOS tube Q3 is connected with the output end of the negative voltage starting module, the third resistor R3 and the gate of the MOS tube Q3 are both connected with the control end of the negative voltage starting module, and the other end of the third resistor R3 and the source of the MOS tube Q3 are both connected with the ground end.

[0022] The drain of the MOS tube Q3 is connected with the output end of the negative voltage starting module.

[0023] By adopting the technical scheme, the voltage signal output by the charging module can control the turn-on and turn-off of the MOS tube Q3, when the MOS tube Q3 is turned on, the voltage drop of the transformer can supply power for the second capacitor C2, and the second capacitor C2 stores energy; when the MOS tube Q is turned off, there is a negative voltage released by the second capacitor C2 between the control end of the MOS tube Q3 and the ground end.

[0024] Optionally, the negative voltage starting module further comprises a fourth resistor R4 and a fifth resistor R5.

[0025] The connection position of the third resistor R3 and the source of the MOS tube is connected with one end of the fourth resistor R4 and the fifth resistor R5, and the other end of the fourth resistor R4 and the fifth resistor R5 is connected with the ground end.

[0026] By adopting the technical scheme, the adjustment capability of the negative voltage starting module is increased, and the output impedance is increased.

[0027] Optionally, the rectifier module further comprises a third diode D3, a fourth diode D4, a MOS tube Q4 and a third capacitor C3.

[0028] One end of the third diode D3 and the fourth diode D4 is connected with the output end of the transformer, the connection of the third diode D3 and the fourth diode D4 is connected with the gate and the source of the MOS tube Q4, the drain of the MOS tube Q4 is connected with one end of the third capacitor C3, the connection of the drain of the MOS tube Q4 and the third capacitor C3 is connected with the other end of the third diode D3 and the fourth diode D4, the other end of the third capacitor C3 is connected with the ground end.

[0029] By adopting the technical scheme, the rectification capability of the negative voltage driving circuit is increased, the alternating voltage or unstable voltage output by the transformer is rectified into stable direct current voltage, and thus the stable direct current voltage is output to a certain extent.

[0030] Optionally, the second diode D2 is a Schottky diode.

[0031] In conclusion, the present application at least has the following advantages:

[0032] 1. The purpose of setting the driving module, the charging module and the negative voltage starting module is that when the input level of the negative voltage driving circuit is pulled low by the single-chip microcomputer, the driving module, the charging module and the negative voltage starting module form a negative voltage driving loop, the charging module provides a negative driving voltage to the control end of the negative voltage starting module, so that an additional negative voltage circuit does not need to be designed separately through an auxiliary power transformer, and the negative voltage driving function of the circuit is realized through a simple circuit, and the cost of the circuit is reduced.

[0033] 2. The purpose of setting the rectifier circuit is to increase the rectification capability of the negative voltage driving circuit, rectify the alternating voltage or unstable voltage output by the transformer into stable direct current voltage, and thus output the stable direct current voltage to a certain extent. BRIEF DESCRIPTION OF DRAWINGS

[0034] Figure 1 is a structural block diagram of one embodiment of the negative voltage driving circuit of the present application;

[0035] Figure 2 is a specific circuit structure schematic diagram of one embodiment of the negative voltage driving circuit of the present application;

[0036] Figure 3 is a specific circuit structure schematic diagram of another embodiment of the negative voltage driving circuit of the present application;

[0037] Legend: 1, driving module; 2, charging module; 3, negative voltage starting module; 4, rectifier module. DETAILED DESCRIPTION

[0038] The present application is combined with the accompanying drawings Figure 1- attached Figure 3 For further detailed description, take an example.

[0039] The present application discloses a negative voltage driving circuit, wherein the negative voltage refers to the state that the voltage has a negative value relative to the ground (or reference voltage point). As an embodiment of the negative voltage driving circuit, as shown in the attached Figure 1 , it comprises a driving module 1 for receiving a control signal output by a single-chip microcomputer, the input end of the driving module 1 is connected with the single-chip microcomputer control signal, and the output end of the driving module 1 outputs a driving voltage.

[0040] As shown in the attached Figure 2 , as an embodiment of the driving module 1, the driving module 1 comprises a first triode Q1, a second triode Q2 and a first capacitor C1; wherein the first triode Q1 is an NPN type triode, and the second triode Q2 is a PNP type triode; the base of the first triode Q1 and the base of the second triode Q2 are both connected with the input end of the driving module 1, the collector of the first triode Q1 is connected with the driving voltage and the first capacitor C1 respectively, one end of the first capacitor C1 is connected with the ground end, and the collector of the second triode Q2 is connected with the ground end; the emitter of the first triode Q1 and the emitter of the second triode Q2 are connected with the output end of the driving module 1.

[0041] In the embodiment, the parameter types of the first triode Q1 and the second triode Q2 are inconsistent, that is, in the first triode Q1 and the second triode Q2, there is any one triode conducting and the other triode cutting off. Assuming that the level signal of the single-chip microcomputer control signal SW1 is low level, the first triode Q1 is cut off, and the second triode Q2 is turned on, when the second triode Q2 is turned on, the driving module 1 forms the ground end; assuming that the level signal of the single-chip microcomputer control signal SW1 is high level, the first triode Q1 is turned on, and the second triode Q2 is cut off, when the first triode Q1 is turned on, the driving voltage of 12V can flow through the first triode Q1 and be output to the charging module 2.

[0042] The charging module 2 is used for providing a charging voltage for a second capacitor C2, the input end of the charging module 2 is connected with the output end of the driving module 1, and the output end of the charging module 2 outputs a reverse driving voltage.

[0043] As shown in the attached Figure 1 and the attached Figure 2As shown, in one embodiment of the charging module 2, the charging module 2 includes a first resistor R1, a second resistor R2, a first diode D1, a second capacitor C2, and a second diode D2; wherein, the second diode D2 is a Schottky diode; one end of the first resistor R1, the second resistor R2, and the first diode D1 are all connected to the input terminal of the charging module, the other end of the first resistor R1, the second resistor R2, and the first diode D1 are all connected to the second diode D2, and the connection point of the second resistor R2 and the second diode D2 is connected to the second capacitor C2;

[0044] In this embodiment, the first resistor R1 and the second resistor R2 form a voltage divider network. When the first transistor Q1 in the drive module 1 is turned on, the 12V drive voltage supplies power to the second capacitor C2, which stores energy. When the first transistor Q1 is turned off, the second capacitor C2 releases the voltage to supply power. The second capacitor C2, the second diode D2, the first diode D1, and the second transistor Q2 form a grounding loop, charging the second capacitor C2. After the second capacitor C2 is fully charged, it can provide a negative drive voltage to the negative voltage start-up module 3 when the second transistor Q2 is turned on. The second diode D2 prevents the third capacitor C3 from discharging to ground. When the control signal SW1 output by the microcontroller is low, the second transistor Q2 in the drive module 1 is turned on, the second capacitor C2 discharges, and finally a negative drive voltage is output at the output terminal of the charging module 2.

[0045] The negative pressure starting module 3 has its control terminal connected to the output terminal of the charging module 2, its input terminal connected to the transformer, and its output terminal connected to the ground terminal.

[0046] As attached Figure 1 and attached Figure 2 As shown, in one embodiment of the negative voltage start module 3, the negative voltage start module 3 includes a third resistor R3 and a MOSFET Q3; wherein, the MOSFET Q3 is an N-type MOSFET; the drain of the MOSFET Q3 is connected to the output terminal of the negative voltage start module, the gate of the third resistor R3 and the gate of the MOSFET Q3 are both connected to the control terminal of the negative voltage start module, the other end of the third resistor R3 and the source of the MOSFET Q3 are both connected to the ground terminal; the drain of the MOSFET Q3 is connected to the output terminal of the negative voltage start module.

[0047] In this embodiment, the voltage signal output by the charging module 2 can control the conduction and turn-off of the MOSFET Q3. When the MOSFET Q3 is on, the voltage drop of the transformer can supply power to the second capacitor C2, and the second capacitor C2 stores energy. When the MOSFET Q3 is off, there is a negative voltage released by the second capacitor C2 between the control terminal of the MOSFET Q3 and the ground terminal.

[0048] As shown in the accompanying Figure 2 As a further embodiment of the negative voltage starting module 3, the negative voltage starting module 3 further comprises a fourth resistor R4 and a fifth resistor R5; the connection between the third resistor R3 and the source of the MOS tube is connected to one end of the fourth resistor R4 and the fifth resistor R5, and the other end of the fourth resistor R4 and the fifth resistor R5 is connected to the ground terminal.

[0049] In this embodiment, the fourth resistor R4 and the fifth resistor R5 increase the adjustment capability of the negative voltage starting module 3, the output impedance, so as to reduce the influence of the subsequent circuit on the negative voltage starting module 3 to a certain extent.

[0050] As shown in the accompanying Figure 3 In order to increase the rectification capability of the power supply circuit, a rectification module 4 is further included, which is used for rectifying the voltage output by the transformer; the input end of the rectification module 4 is connected to the output end of the transformer, and the output end of the rectification module 4 is used for outputting the rectified voltage.

[0051] As shown in the accompanying Figure 2 As a further embodiment of the rectification module 4, the rectification module 4 further comprises a third diode D3, a fourth diode D4, a MOS tube Q4 and a third capacitor C3; wherein the MOS tube Q4 is a P-type MOS tube; one end of the third diode D3 and the fourth diode D4 is connected to the output end of the transformer, the connection between the third diode D3 and the fourth diode D4 is connected to the gate and the source of the MOS tube Q4, the drain of the MOS tube Q4 is connected to one end of the third capacitor C3, the connection between the drain of the MOS tube Q4 and the third capacitor C3 is connected to the other end of the third diode D3 and the fourth diode D4, and the other end of the third capacitor C3 is connected to the ground terminal.

[0052] In this embodiment, the third diode D3, the fourth diode D4, the MOS tube Q4 and the third capacitor C3 increase the rectification capability of the negative voltage driving circuit, rectify the alternating voltage or unstable voltage output by the transformer into stable direct current voltage, so as to output stable direct current voltage to a certain extent.

[0053] The implementation principle of the present embodiment is as follows:

[0054] When the single-chip microcomputer pulls down the input level of the negative voltage driving circuit, the driving module 1, the charging module 2 and the negative voltage starting module 3 form a negative voltage driving loop, the charging module 2 provides a negative driving voltage to the control terminal of the negative voltage starting module 3, so that it is not necessary to additionally design a negative voltage circuit through an auxiliary power transformer, and the negative voltage driving function of the circuit can be realized through a simple circuit, and the cost of the circuit can be reduced.

[0055] The above are all preferred embodiments of the present application, and do not limit the protection scope of the present application, so that: all equivalent changes made according to the structure, shape, principle of the present application should be covered in the protection scope of the present application.

Claims

1. A negative voltage drive circuit, characterized by, include: A driver module, the input terminal of which is connected to the control signal of the microcontroller; A charging module, wherein the input terminal of the charging module is connected to the output terminal of the driving module, and the output terminal of the charging module outputs a negative driving voltage; A negative pressure starting module is provided, wherein the control terminal of the negative pressure starting module is connected to the output terminal of the charging module, the input terminal of the negative pressure starting module is connected to the transformer, and the output terminal of the negative pressure starting module is connected to the ground terminal.

2. The negative voltage driving circuit according to claim 1, wherein: It also includes a rectifier module, which is used to rectify the voltage output by the transformer; the input terminal of the rectifier module is connected to the output terminal of the transformer, and the output terminal of the rectifier module is used to output the rectified voltage.

3. The negative voltage driving circuit according to claim 1, wherein: The driving module includes a first transistor Q1, a second transistor Q2, and a first capacitor C1. The first transistor Q1 is an NPN transistor, and the second transistor Q2 is a PNP transistor. The bases of the first transistor Q1 and the second transistor Q2 are both connected to the input terminal of the driving module. The collector of the first transistor Q1 is connected to the driving voltage and the first capacitor C1, respectively. One end of the first capacitor C1 is connected to the ground terminal. The collector of the second transistor Q2 is connected to the ground terminal. The emitters of the first transistor Q1 and the second transistor Q2 are connected to the output terminal of the driving module.

4. The negative voltage driving circuit according to claim 3, wherein: The charging module includes a first resistor R1, a second resistor R2, a first diode D1, a second capacitor C2, and a second diode D2; One end of the first resistor R1, the second resistor R2 and the first diode D1 are all connected to the input terminal of the charging module, and the other end of the first resistor R1, the second resistor R2 and the first diode D1 are all connected to the second diode D2. The connection between the second resistor R2 and the second diode D2 is connected to the second capacitor C2. The connection between the second capacitor C2 and the second diode D2 is connected to the output terminal of the charging module.

5. A negative voltage drive circuit according to claim 4, wherein: The negative pressure start-up module includes a third resistor R3 and a MOSFET Q3; The drain of the MOS transistor Q3 is connected to the output terminal of the negative voltage start-up module. The third resistor R3 and the gate of the MOS transistor Q3 are both connected to the control terminal of the negative voltage start-up module. The other end of the third resistor R3 and the source of the MOS transistor Q3 are both connected to the ground terminal. The drain of the MOS transistor Q3 is connected to the output terminal of the negative voltage start-up module.

6. A negative voltage drive circuit according to claim 5, wherein: The negative pressure start-up module also includes a fourth resistor R4 and a fifth resistor R5; The connection points of the third resistor R3 and the source of the MOS transistor are both connected to one end of the fourth resistor R4 and the fifth resistor R5, and the other ends of the fourth resistor R4 and the fifth resistor R5 are both connected to the ground terminal.

7. The negative voltage driving circuit according to claim 2, wherein: The rectifier module also includes a third diode D3, a fourth diode D4, a MOSFET Q4, and a third capacitor C3; One end of the third diode D3 and the fourth diode D4 is connected with the output end of the transformer, the connection of the third diode D3 and the fourth diode D4 is connected with the gate and the source of the MOS tube Q4, the drain of the MOS tube Q4 is connected with one end of the third capacitor C3, the connection of the drain of the MOS tube Q4 and the third capacitor C3 is connected with the other end of the third diode D3 and the fourth diode D4, the other end of the third capacitor C3 is connected with the ground end.

8. The negative voltage driving circuit according to claim 4, wherein: The second diode D2 is a Schottky diode.

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