Driving circuit, voltage conversion circuit and energy storage power supply

Abstract

The application relates to a driving circuit, a voltage conversion circuit and an energy storage power supply. The driving circuit is used for driving a conversion circuit. The conversion circuit comprises a freewheeling tube and a power tube. The driving circuit comprises a switching module, a first end of the switching module is connected with a gate of the freewheeling tube, and a second end is grounded; a detection module, an input end of the detection module is connected with a driving signal output end of a driving chip, and the detection module is used for outputting a first control signal when a driving signal output by the driving chip is represented as an off driving signal of the freewheeling tube; a switching control module, an input end of the switching control module is connected with an output end of the detection module, and an output end of the switching control module is connected with a control end of the switching module; and the switching control module is used for controlling the switching module to be turned on when the first control signal is received. Voltage peak of the freewheeling tube is avoided in x stage time, so that the circuit is protected safely.

Description

Technical Field

[0001] This application relates to the field of electronic circuit technology, and in particular to a driving circuit, a voltage conversion circuit, and an energy storage power supply. Background Technology

[0002] The voltage conversion circuit with two switching transistors includes two MOSFETs (power transistor Q1 and freewheeling transistor Q2), an inductor L1, and an output capacitor. Power transistor Q1 acts as the main switch, controlling the energy flow from the input to the inductor. Freewheeling transistor Q2 replaces the freewheeling diode in a traditional voltage conversion circuit and is called a synchronous rectifier. When power transistor Q1 is on, current flows through the inductor to power the output capacitor and the load, and the inductor stores energy. When power transistor Q1 is off, since the inductor current cannot change abruptly, the current continues to flow to the load through freewheeling transistor Q2 (or the body diode of freewheeling transistor Q2), completing the freewheeling process.

[0003] In practical applications, during the conduction process of power transistor Q1, a small voltage spike may appear in freewheeling transistor Q2 in the x-stage of the time axis, which may easily turn on freewheeling transistor Q2, thereby short-circuiting the input voltage. The sudden surge of large current may damage the MOSFET. Summary of the Invention

[0004] Therefore, it is necessary to provide a driving circuit, a voltage conversion circuit, and an energy storage power supply.

[0005] In a first aspect, this application provides a driving circuit for driving a conversion circuit, the conversion circuit including a freewheeling transistor and a power transistor, comprising:

[0006] A switching module, wherein the first terminal of the switching module is connected to the gate of the freewheeling diode, and the second terminal is grounded;

[0007] The detection module has its input terminal connected to the drive signal output terminal of the driver chip. The detection module is used to output a first control signal when the drive signal output by the driver chip represents the disconnection drive signal of the freewheeling diode.

[0008] A switch control module is provided, wherein the input terminal of the switch control module is connected to the output terminal of the detection module, and the output terminal of the switch control module is connected to the control terminal of the switch module; the switch control module is used to control the switch module to conduct when it receives the first control signal. In one embodiment, the detection module is further used to output a second control signal when the drive signal output by the driver chip represents the conduction drive signal of the freewheeling diode;

[0009] The switch control module is also used to control the switch module to disconnect when the second control signal is received.

[0010] In one embodiment, the detection module includes:

[0011] A unidirectional conduction unit, wherein the anode of the unidirectional conduction unit is connected to the drive signal output terminal of the drive chip;

[0012] The detection unit has a first input terminal connected to the cathode of the unidirectional conduction unit, a second input terminal connected to a power supply, and an output terminal connected to the input terminal of the control switch module.

[0013] The unidirectional conduction unit is turned off when the drive signal output by the driver chip represents the disconnect drive signal of the freewheeling diode, and the detection unit outputs a first control signal according to the power supply; the unidirectional conduction unit is turned on when the drive signal output by the driver chip represents the conduction drive signal of the freewheeling diode, and the detection unit outputs a second control signal according to the power supply and the drive signal.

[0014] In one embodiment, the detection unit includes:

[0015] A Zener diode, the positive terminal of which is connected to the cathode of the unidirectional conduction unit;

[0016] The fifth switching transistor has its emitter connected to the power supply and its collector serving as the output of the detection unit.

[0017] The sixth switch has its emitter connected to the base of the fifth switch, its collector grounded, and its base connected to the negative terminal of the Zener diode.

[0018] In one embodiment, the switch control module is used to control the switch module to turn on when it receives the first control signal; and to control the switch module to turn off when the timer expires.

[0019] In one embodiment, the switch control module includes:

[0020] A timing unit is provided, wherein the input terminal of the timing unit is connected to the output terminal of the detection module, and the output terminal of the timing unit is connected to the control terminal of the switch module. The timing unit is used to control the switch module to turn on when the detection module outputs a first control signal, and to control the switch module to turn off when the timing time of the timing unit arrives.

[0021] In one embodiment, the timing unit includes a twentieth resistor and a third capacitor. The first end of the twentieth resistor is connected to the output terminal of the detection module, the second end of the twentieth resistor is connected to the first end of the third capacitor, and the second end of the third capacitor is connected to the control terminal of the switching module.

[0022] The third capacitor is used to control the switch module to turn on when the detection module outputs the first control signal, and the third capacitor stores energy. When the energy storage time of the third capacitor reaches the timing time, the switch module is controlled to turn off.

[0023] In one embodiment, the switch control module further includes:

[0024] A reset unit is provided, with its two ends connected to the two ends of the third capacitor. The reset unit is used to consume the energy stored in the third capacitor when the detection module outputs the second control signal.

[0025] Secondly, this application also provides a voltage conversion circuit, the voltage conversion circuit comprising:

[0026] A conversion circuit, the conversion circuit including a freewheeling transistor and a power transistor;

[0027] A driver chip is used to drive the conversion circuit;

[0028] In the aforementioned driving circuit, the input terminal of the driving circuit is connected to the driving signal output terminal of the driving chip, and the output terminal of the driving circuit is connected to the gate of the freewheeling diode.

[0029] Thirdly, this application also provides an energy storage power supply, including the voltage conversion circuit described above.

[0030] In the aforementioned driving circuit, voltage conversion circuit, and energy storage power supply, when the driving signal output by the driving chip represents a disconnection driving signal for the freewheeling diode, the detection module outputs a first control signal. Upon receiving the first control signal, the switch control module controls the switch module to turn on, thereby pulling down the gate voltage of the freewheeling diode. In this way, during the conduction process of the switch, the gate voltage of the freewheeling diode is pulled down, and the freewheeling diode will not conduct, thus protecting the circuit safety. Attached Figure Description

[0031] To more clearly illustrate the technical solutions in the embodiments of this application or the conventional technology, the drawings used in the description of the embodiments or the conventional technology will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0032] Figure 1 This is a schematic diagram of a voltage conversion circuit according to one embodiment;

[0033] Figure 2 The waveform diagram shows the voltage applied to the drain and source of the freewheeling diode Q2 in one embodiment.

[0034] Figure 3 The waveform diagrams for power transistor Q1 and freewheeling transistor Q2 in one embodiment are shown.

[0035] Figure 4 for Figure 1 The peripheral circuit of the freewheeling diode Q2 in the illustrated embodiment;

[0036] Figure 5 for Figure 4 A simplified circuit of the peripheral circuit in the illustrated embodiment;

[0037] Figure 6 for Figure 5 The equivalent circuit of the simplified circuit in the illustrated embodiment;

[0038] Figure 7 This is a block diagram of the drive circuit in one embodiment;

[0039] Figure 8 This is a circuit diagram of the driving circuit in one embodiment;

[0040] Figure 9 This is a schematic diagram of a driver chip in one embodiment. Detailed Implementation

[0041] To facilitate understanding of this application, a more complete description will be provided below with reference to the accompanying drawings, which illustrate embodiments of the present application. However, the present application can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided so that the disclosure of this application will be thorough and complete.

[0042] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.

[0043] It is understood that the terms "first," "second," etc., used herein may be used to describe various elements, but these elements are not limited by these terms. These terms are only used to distinguish one element from another. For example, without departing from the scope of this application, a first resistor may be referred to as a second resistor, and similarly, a second resistor may be referred to as a first resistor. Both the first resistor and the second resistor are resistors, but they are not the same resistor.

[0044] It is understood that the term "connection" in the following embodiments should be understood as "electrical connection," "communication connection," etc., if the connected circuits, modules, units, etc., have electrical signal or data transmission with each other.

[0045] It is understandable that "at least one" refers to one or more, and "multiple" refers to two or more. "At least a part of an element" refers to part or all of an element.

[0046] When used herein, the singular forms of “a,” “an,” and “the” may also include the plural forms unless the context clearly indicates otherwise. It should also be understood that the terms “comprising / including” or “having,” etc., specify the presence of the stated features, wholes, steps, operations, components, parts, or combinations thereof, but do not preclude the possibility of the presence or addition of one or more other features, wholes, steps, operations, components, parts, or combinations thereof. Meanwhile, the term “and / or” as used in this specification includes any and all combinations of the associated listed items.

[0047] like Figures 1 to 6 As shown, Figure 1 In one embodiment, a voltage conversion circuit with two switches is provided. This circuit includes a power transistor Q1 and a freewheeling transistor Q2. When the circuit is in a buck state, power transistor Q1 and freewheeling transistor Q2 are complementaryly conducting. When power transistor Q1 is closed, it is equivalent to applying a voltage drop across the drain (D) and source (S) terminals of freewheeling transistor Q2. Figure 2 The voltage F(t) is shown.

[0048] In practical use, the VGS and VDS of the power transistor Q1 and the VGS of the freewheeling transistor Q2 are as follows: Figure 3 As shown, during the conduction of the power transistor Q1, a small voltage spike will appear in the x-stage of the time axis due to the VGS of the freewheeling transistor Q2. This spike can easily turn on the freewheeling transistor Q2, thereby short-circuiting the input voltage. The sudden surge of large current can damage the power transistor Q1.

[0049] To solve this technical problem, the drive resistor of the freewheeling diode Q2 is grounded, and the external circuit of the freewheeling diode Q2 can be changed as follows: Figure 4 As shown.

[0050] To simplify calculations, such as Figure 5 As shown, the first resistor R1 is equivalent to C. GS The impedance of the first resistor is equal to the impedance of the second resistor R2, which is equivalent to the impedance of the parasitic inductance. The impedance of the third resistor R3 is equivalent to the impedance of C. DG The impedance of the fourth resistor R4 is equivalent to C. DS The impedance of the zeroth resistance R0 is equivalent to the impedance of the driving resistor.

[0051] To facilitate the calculation of the driving voltage between point G and point S, i.e., the freewheeling diode Q2, the delta circuit composed of the first resistor R1, the third resistor R3, and the fourth resistor R4 is converted into a Y-shape, as shown below. Figure 6 As shown.

[0052] Therefore, we can obtain the transfer function for the input voltage between the drain (D) and the gate (S), and the output voltage between the gate (G) and the source (S). The Laplace equivalent model of this transfer function is:

[0053]

[0054] Here, s is a variable in the Laplace transform, which is related to the frequency f. This is because the voltage waveform applied between the drain D and the gate S during this period can be regarded as a sloping line with a slope of K. After performing a Fourier transform on it, it is found that the transformed result is continuous and convergent, with most of its frequency components concentrated in the low frequency range.

[0055] Furthermore, its transfer function shows that as the frequency f approaches 0, the smaller the equivalent resistance R00, the smaller the amplitude-frequency response. Therefore, we can conclude that the smaller the resistance value of the equivalent resistance R00, the smaller the voltage between G and S at this time for the freewheeling diode Q2.

[0056] However, if the resistance value of the equivalent resistor R00 is directly modified, in order not to affect the normal turn-off and to avoid being turned on by voltage spikes, the turn-off speed of the freewheeling transistor Q2 will be too fast, and the voltage and current stress will be too great.

[0057] To solve the above technical problems, combined with Figure 7 and Figure 8 As shown, this application provides a driving circuit, including: a switching module 300, a detection module 100, and a switching control module 200.

[0058] The first terminal of the switching module 300 is connected to the gate of the freewheeling diode Q2 of the conversion circuit, and the second terminal is grounded; the input terminal of the detection module 100 is connected to the drive signal output terminal of the driver chip U1; the input terminal of the switch control module 200 is connected to the output terminal of the detection module 100; and the output terminal of the switch control module 200 is connected to the control terminal of the switching module 300.

[0059] The detection module 100 outputs a first control signal when the drive signal L2 output by the driver chip U1 represents a disconnect drive signal for the freewheeling diode Q2. The switch control module 200 controls the switch module 300 to turn on when it receives the first control signal.

[0060] In some optional embodiments, the detection module 100 is further configured to output a second control signal when the drive signal L2 output by the drive chip U1 is characterized as the conduction drive signal of the freewheeling diode Q2; the switch control module 200 is further configured to control the switch module 300 to disconnect when the second control signal is received.

[0061] Specifically, in combination Figure 1 and Figure 9 As shown, the driver chip U1 is used to output the drive signal L2, which can drive... Figure 1 The voltage conversion circuit shown illustrates the switching on and off of the freewheeling diode Q2. The drive signal L2 includes a first-level signal and a second-level signal. The first-level signal is a low-level signal (i.e., drive signal L2 represents the disconnection drive signal for the freewheeling diode Q2), and the second-level signal is a high-level signal (i.e., drive signal L2 represents the conduction drive signal for the freewheeling diode Q2).

[0062] When the drive signal L2 is at the second level, the freewheeling diode Q2 is turned on, and the current flows through the inductor L1 to supply power to the output capacitor and the load, while the inductor L1 stores energy. When the drive signal L2 is at the first level, the freewheeling diode Q2 is turned off. Since the current in the inductor L1 cannot change abruptly, the current continues to flow to the load through the body diode of the freewheeling diode Q2, completing the freewheeling process.

[0063] Combination Figure 3 As shown, the x-stage time is when the power transistor Q1 is in the on-state, and the freewheeling transistor Q2 completes freewheeling and is in the off-state. To avoid voltage spikes in the freewheeling transistor Q2 during the x-stage time, the detection module 100 outputs a first control signal when the drive signal L2 output by the driver chip U1 represents the disconnection drive signal of the freewheeling transistor Q2. Thus, the switch control module 200 can control the switch module 300 to turn on based on the first control signal, thereby controlling the freewheeling transistor Q2. That is, controlling the switch module 300 to turn on so that the gate of the freewheeling transistor Q2 is grounded, that is, pulling down the gate voltage of the freewheeling transistor Q2, so that the freewheeling transistor Q2 will not turn on during the x-stage time, thereby protecting the circuit safety.

[0064] Specifically, when the drive signal L2 is the first level signal (i.e., the drive signal L2 represents the disconnection drive signal for the freewheeling transistor Q2), because the inductor current of inductor L1 cannot change abruptly, inductor L1 still flows from the gate to the drain through the body diode of the freewheeling transistor Q2. At this time, the voltage between the drain and gate of the power transistor Q1 remains high and unchanged. When the drive signal L2 output by the driver chip U1 causes the freewheeling transistor Q2 to be in the off state, combined with... Figure 3 Next is the x-stage time. To avoid voltage spikes in the freewheeling diode Q2 during the x-stage time, the switch control module 200 controls the switch module 300 to turn on, thereby pulling down the gate voltage of the freewheeling diode Q2 to protect the circuit safety.

[0065] When the drive signal L2 is the second level signal, and the freewheeling diode Q2 is turned on, in order to avoid the influence of the switching module 300 on the freewheeling diode Q2, the detection module 100 outputs a second control signal. When the switching control module 200 receives the second control signal, it controls the switching module 300 to turn off, and the freewheeling diode Q2 is turned on normally.

[0066] In the above embodiments, when the drive signal L2 output by the driver chip U1 represents the cut-off drive signal of the freewheeling transistor Q2, the switch module 300 is turned on to pull the gate of the freewheeling transistor Q2 low, thus avoiding voltage spikes in the freewheeling transistor Q2; when the drive signal L2 output by the driver chip U1 represents the turn-on drive signal of the freewheeling transistor Q2, the switch module 300 is turned off, which does not affect the normal conduction of the freewheeling transistor Q2.

[0067] In some optional embodiments, the detection module 100 includes a unidirectional conduction unit 110 and a detection unit 120, wherein the anode of the unidirectional conduction unit 110 is connected to the drive signal output terminal of the drive chip U1, the first input terminal of the detection unit 120 is connected to the cathode of the unidirectional conduction unit 110, the second input terminal of the detection unit 120 is connected to the power supply VCC, and the output terminal of the detection unit 120 is connected to the input terminal of the switch control module 200.

[0068] The unidirectional conduction unit 110 can be the fifth diode D5.

[0069] The unidirectional conduction unit 110 is cut off when the drive signal L2 output by the driver chip U1 represents the disconnect drive signal of the freewheeling diode Q2, and the detection unit outputs a first control signal according to the power supply VCC; the unidirectional conduction unit 110 is turned on when the drive signal L2 output by the driver chip U1 represents the turn-on drive signal of the freewheeling diode Q2, and the detection unit 120 outputs a second control signal according to the power supply VCC and the drive signal L2.

[0070] When the drive signal L2 output by the driver chip U1 represents the disconnect drive signal of the freewheeling diode Q2, the unidirectional conduction unit 110 is turned off, so the detection unit 120 outputs the first control signal according to the power supply VCC, and then the switch control module 200 controls the switch module 300 to turn on, so as to pull down the gate voltage of the freewheeling diode Q2. After the freewheeling diode Q2 is turned off, no voltage spike will appear.

[0071] When the drive signal L2 output by the driver chip U1 represents the conduction drive signal of the freewheeling diode Q2, the unidirectional conduction unit 110 is turned on, so the detection unit 120 outputs a second control signal according to the power supply VCC and the drive signal L2, and then the switch control module 200 controls the switch module 300 to be turned off, without affecting the normal conduction of the freewheeling diode Q2.

[0072] In some optional embodiments, the detection unit includes: a Zener diode DA1, a fifth switch Q5, and a sixth switch Q6. The positive terminal of the Zener diode DA1 is connected to the cathode of the unidirectional conduction unit 110. The emitter of the fifth switch Q5 is connected to a power supply, and the collector of the fifth switch Q5 serves as the output of the detection unit 120. The emitter of the sixth switch Q6 is connected to the base of the fifth switch Q5, the collector of the sixth switch Q6 is grounded, and the base of the sixth switch Q6 is connected to the negative terminal of the Zener diode.

[0073] When the drive signal L2 output by the driver chip U1 represents the disconnect drive signal of the freewheeling transistor Q2, the sixth switch Q6, the fifth switch Q5, and the Zener diode DA1 are turned on, so as to output the first control signal through the collector of the fifth switch Q5; when the drive signal L2 output by the driver chip U1 represents the turn-on drive signal of the freewheeling transistor Q2, the fifth switch Q5, the sixth switch Q6, and the Zener diode DA1 are turned off, so as to output the second control signal through the collector of the fifth switch Q5.

[0074] When the drive signal L2 output by the driver chip U1 represents the disconnection drive signal of the freewheeling diode Q2, that is, when the drive signal L2 is the first level signal, the fifth diode D5 is cut off. Therefore, the clamping voltage of the cathode of the fifth diode D5 is also pulled down, and the voltage difference between the high level VCC and the fifth diode D5 becomes larger. When the voltage of the drive signal L2 output by the driver chip U1 keeps the freewheeling diode Q2 in the cut-off state, the fifth switch Q5, the Zener diode DA1 and the sixth switch Q6 are turned on, so the detection unit 120 outputs the first control signal. And because the sixth switch Q6 is turned on, the power supply VCC flows into the subsequent switch control module 200.

[0075] When the drive signal L2 output by the driver chip U1 represents the conduction drive signal of the freewheeling diode Q2, that is, when the drive signal L2 is the second level signal, the fifth diode D5 is turned on, the clamping voltage of the cathode of the fifth diode D5 is pulled high, the voltage difference between the power supply VCC and the fifth diode D5 becomes smaller, the fifth switch Q5 is turned off, the Zener diode DA1 is turned off, and the sixth switch Q6 is turned off, thereby detecting the second control signal of the detection unit 120. Since the sixth switch Q6 is turned off, the power supply VCC does not flow into the subsequent switch control module 200.

[0076] In some optional embodiments, the switch control module 200 is used to control the switch module 300 to turn on when a first control signal is received; and to control the switch module 300 to turn off when a timed period is reached.

[0077] The timing period is approximately the same as the x-stage time, or the timing period is greater than or equal to the x-stage time.

[0078] To avoid affecting the normal conduction of the freewheeling diode Q2, combined with Figure 3 The switch control module 200 controls the switch module 300 to be turned on only during the x-stage time to pull down the voltage of the gate of the freewheeling diode Q2, and controls the switch module 300 to be turned off during the non-x-stage time to avoid affecting the normal operation of the freewheeling diode Q2.

[0079] In some optional embodiments, the switch control module 200 includes a timing unit 210, the input terminal of which is connected to the output terminal of the detection module 100, and the output terminal of which is connected to the control terminal of the switch module 300. The timing unit 210 is used to control the switch module 300 to turn on when the detection module 100 outputs a first control signal, and to control the switch module 300 to turn off when the timing time of the timing unit 210 arrives.

[0080] The timing unit 210 is used to control the conduction time of the switching module 300, so that the switching module 300 only conducts when Figure 3 The circuit is turned on during the x-stage shown to pull down the gate voltage of the freewheeling diode Q2.

[0081] In some optional embodiments, the timing unit 210 includes a twentieth resistor R20 and a third capacitor C3. The first end of the twentieth resistor R20 is connected to the output terminal of the detection module 100, and the second end of the twentieth resistor R20 is connected to the first end of the third capacitor C3. The second end of the third capacitor C3 is connected to the control terminal of the switch module 300. The third capacitor C3 is used to control the switch module 300 to conduct when the detection module 100 outputs a first control signal, and the third capacitor C3 stores energy. When the energy storage time of the third capacitor C3 reaches the timing time, the switch module 300 is turned off.

[0082] In this embodiment, the timing unit 210 is described using an RC charging circuit as an example. In other embodiments, the timing unit 210 may also take other forms, which are not specifically limited here.

[0083] When the drive signal L2 is the first level signal, that is, when the drive signal L2 output by the drive chip U1 represents the disconnect drive signal of the freewheeling transistor Q2, the first control signal is output. That is, the power supply VCC flows into the subsequent switch control module 200 under the control of the detection module 100, so as to charge the third capacitor C3. That is, because the fifth switch Q5 is turned on, the voltage on the emitter of the fifth switch Q5 passes through the twentieth resistor R20 and the third capacitor C3 to turn on the seventh switch Q7, thereby pulling the gate of the freewheeling transistor Q2 low.

[0084] Furthermore, as the voltage across the third capacitor C3 gradually increases, the voltage between the gate and source of the seventh switch Q7 in the switching module 300 decreases, thereby causing the seventh switch Q7 to turn off. In other words, during the x-stage time, the drive resistor R00 is bypassed, thus reducing the peak voltage.

[0085] In some optional embodiments, the switch control module 200 further includes a reset unit 220, the two ends of which are respectively connected to the two ends of the third capacitor C3. The reset unit 220 is used to consume the energy stored in the third capacitor C3 when the detection module 100 outputs the second control signal.

[0086] Combination Figure 8 As shown, the reset unit 220 is used to output a second control signal when the drive signal L2 is a second level signal, that is, the drive signal L2 output by the drive chip U1 represents the conduction drive signal of the freewheeling diode Q2, and the power supply VCC does not flow into the subsequent switch control module 200. As a result, the third capacitor C3 of the switch control module 200 releases the stored energy to prepare for the next cycle of charging.

[0087] Combination Figure 8As shown, the reset unit 220 includes a tenth resistor R10 and a sixth diode D6. The first end of the tenth resistor R10 is connected to the first end of the third capacitor C3, and the second end of the tenth resistor R10 is grounded. The cathode of the sixth diode D6 is connected to the second end of the third capacitor C3, and the anode of the sixth diode D6 is grounded.

[0088] In this case, when the drive signal L2 is the second level signal, the power supply VCC does not flow into the subsequent switch control module 200. The energy on its third capacitor C3 is consumed through the circuit composed of the tenth resistor R10 and the sixth diode D6, preparing for the next cycle of charging.

[0089] For ease of understanding, combine Figure 1 , Figure 8 as well as Figure 9 As shown, this application also provides a voltage conversion circuit, which includes a conversion circuit, a driver chip U1, and a driving circuit. The conversion circuit includes a freewheeling transistor Q2 and a power transistor Q1. The driver chip U1 is used to drive the conversion circuit. The input terminal of the driving circuit is connected to the driving signal output terminal of the driver chip U1, and the output terminal of the driving circuit is connected to the gate of the freewheeling transistor Q2 of the conversion circuit.

[0090] When MCU_L1 of driver chip U1 is low, the drive signal L2 output by driver chip U1 is the first level signal, which represents the disconnection drive signal of freewheeling transistor Q2. Because the inductor current of inductor L1 cannot change abruptly, its current still flows from the gate to the drain through the body diode of freewheeling transistor Q2. At this time, the VDS value of its power transistor Q1 remains unchanged, and VDS is maintained in a high voltage state. Figure 3 In the AB phase, because the drive signal L2 output by the driver chip U1 is a first-level signal, the clamping voltage originally passing through the cathode of the fifth diode D5 is also pulled low, and the voltage difference between the power supply VCC and the cathode of the fifth diode D5 increases; when the drive signal L2 output by the driver chip U1 causes the freewheeling diode Q2 to be in the off state, that is... Figure 3 During the x-stage time, power transistor Q1 is transitioning from off to on, freewheeling transistor Q2 is off, and the drive signal L2 output by driver chip U1 turns on the fifth switch Q5, the sixth switch Q6, and the Zener diode DA1. Because the fifth switch Q5 is on, the voltage across its emitter, through the twentieth resistor R20 and the third capacitor C3, turns on the seventh switch Q7. The gate of the freewheeling transistor Q2 in its voltage conversion circuit is directly pulled to ground through the seventh switch Q7. The power supply VCC flows through the twentieth resistor R20 and into the third capacitor C3. The voltage across the third capacitor C3 gradually increases, causing the voltage between the gate and source of the seventh switch Q7 to decrease, thus turning off the seventh switch Q7. This achieves the goal of reducing the drive resistor R00 only during the x-stage time, thereby reducing the peak voltage.

[0091] When MCU_L1 of driver chip U1 is set high, the drive signal L2 output by driver chip U1 is the second level signal, which represents the conduction drive signal of freewheeling diode Q2. The clamping voltage of the cathode of the fifth diode D5 is pulled high, the voltage difference between the power supply VCC and the cathode of the fifth diode D5 becomes smaller, causing the fifth switch Q5 and the sixth switch Q6 to turn off, the Zener diode DA1 to be cut off, and the energy on the third capacitor C3 is consumed through the circuit composed of the tenth resistor R10 and the sixth diode D6, preparing for the next cycle of charging.

[0092] When power transistor Q1 is turned off and freewheeling transistor Q2 is turned off, the seventh switch Q7 pulls the gate of freewheeling transistor Q2 low to avoid voltage spikes in freewheeling transistor Q2. When power transistor Q1 is turned on, the energy on the third capacitor C3 is dissipated through the circuit composed of the tenth resistor R10 and the sixth diode D6, preparing for the next charging cycle.

[0093] In other embodiments, this application also provides an energy storage power supply, which includes a voltage conversion circuit according to any of the above embodiments.

[0094] In the description of this specification, references to terms such as "some embodiments," "other embodiments," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this application. In this specification, the illustrative descriptions of the above terms do not necessarily refer to the same embodiments or examples.

[0095] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0096] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of this application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these modifications and improvements all fall within the protection scope of this application. Therefore, the protection scope of this application should be determined by the appended claims.

Claims

1. A driving circuit for driving a conversion circuit, the conversion circuit comprising a freewheeling transistor and a power transistor, characterized in that, include: A switching module, wherein the first terminal of the switching module is connected to the gate of the freewheeling diode, and the second terminal is grounded; The detection module has its input terminal connected to the drive signal output terminal of the driver chip. The detection module is used to output a first control signal when the drive signal output by the driver chip represents the disconnection drive signal of the freewheeling diode. A switch control module is provided, wherein the input terminal of the switch control module is connected to the output terminal of the detection module, and the output terminal of the switch control module is connected to the control terminal of the switch module; the switch control module is used to control the switch module to be turned on when the first control signal is received, and to control the switch module to be turned off when a timed period is reached, wherein the timed period is greater than or equal to the duration of the voltage spike that turns on the freewheeling diode, and less than the duration of the drive signal that turns off the freewheeling diode; The switch control module includes: A timing unit is provided, wherein the input terminal of the timing unit is connected to the output terminal of the detection module, and the output terminal of the timing unit is connected to the control terminal of the switch module. The timing unit is used to control the switch module to turn on when the detection module outputs a first control signal, and to control the switch module to turn off when the timing time of the timing unit arrives. A reset unit is provided, with its two ends connected to the two ends of the third capacitor in the timing unit. The reset unit is used to consume the energy stored in the third capacitor when the detection module outputs the second control signal.

2. The driving circuit according to claim 1, characterized in that, The detection module is also used to output a second control signal when the drive signal output by the drive chip is characterized as the conduction drive signal of the freewheeling tube; The switch control module is also used to control the switch module to disconnect when the second control signal is received.

3. The driving circuit according to claim 1, characterized in that, The detection module includes: A unidirectional conduction unit, wherein the anode of the unidirectional conduction unit is connected to the drive signal output terminal of the drive chip; The detection unit has a first input terminal connected to the cathode of the unidirectional conduction unit, a second input terminal connected to a power supply, and an output terminal connected to the input terminal of the switch control module. The unidirectional conduction unit is turned off when the drive signal output by the driver chip represents the disconnect drive signal of the freewheeling diode, and the detection unit outputs a first control signal according to the power supply; the unidirectional conduction unit is turned on when the drive signal output by the driver chip represents the conduction drive signal of the freewheeling diode, and the detection unit outputs a second control signal according to the power supply and the drive signal.

4. The driving circuit according to claim 3, characterized in that, The detection unit includes: A Zener diode, the positive terminal of which is connected to the cathode of the unidirectional conduction unit; The fifth switching transistor has its emitter connected to the power supply and its collector serving as the output of the detection unit. The sixth switch has its emitter connected to the base of the fifth switch, its collector grounded, and its base connected to the negative terminal of the Zener diode.

5. The driving circuit according to claim 1, characterized in that, The timing unit includes a twentieth resistor and a third capacitor. The first end of the twentieth resistor is connected to the output terminal of the detection module, the second end of the twentieth resistor is connected to the first end of the third capacitor, and the second end of the third capacitor is connected to the control terminal of the switching module. The third capacitor is used to control the switch module to turn on when the detection module outputs the first control signal, and the third capacitor stores energy. When the energy storage time of the third capacitor reaches the timing time, the switch module is controlled to turn off.

6. A voltage conversion circuit, characterized in that, The voltage conversion circuit includes: A conversion circuit, the conversion circuit including a freewheeling transistor and a power transistor; A driver chip is used to drive the conversion circuit; The driving circuit according to any one of claims 1 to 5, wherein the input terminal of the driving circuit is connected to the driving signal output terminal of the driving chip, and the output terminal of the driving circuit is connected to the gate of the freewheeling diode.

7. An energy storage power source, characterized in that, Includes the voltage conversion circuit according to claim 6.

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