Power tube boost drive circuit

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By designing a power tube boost driving circuit including power supply module, isolation drive module, boost module, power tube and sampling module in a high-voltage power supply system, the damage problem of NMOS under reverse voltage is solved, and efficient circuit protection and efficiency improvement is achieved.

CN119628382APending Publication Date: 2025-03-14CHONGQING PINGWEI ENTERPRISE

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Patent Information

Application Number: CN202411926841.5
Authority / Receiving Office: CN · China
Patent Type: Applications(China)
Current Assignee / Owner
Filing Date: 2024-12-25
Publication Date: 2025-03-14

AI Technical Summary

Technical Problem

In traditional high-voltage power supply systems, NMOS transistors are easily damaged under reverse voltage, making it difficult to achieve reverse connection protection.

Method used

A power tube boost driving circuit is designed, including a power supply module, an isolation drive module, a boost module, a power tube and a sampling module. The boost process is controlled through the pulse control signal, and the boost output is sampled, and the pulse control signal is adjusted to prevent overvoltage.

Benefits of technology

It effectively prevents overvoltage, improves the efficiency of the circuit, prevents on-surges, and realizes high-voltage driving and reverse connection protection for NMOS.

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Abstract

The invention provides a power tube boost drive circuit comprising a power supply module used for providing high voltage input; the isolation driving module is powered by the power supply module and generates a pulse control signal; the boosting module is used for performing boosting switching operation on the basis of the pulse control signal; the power tube is connected with the output end of the boosting module so as to conduct the boosted voltage to a load; and the sampling module is used for sampling the output end of the boosting module and feeding back the sampling voltage to the isolation driving module, so that the isolation driving module adjusts the pulse control signal based on the sampling voltage. According to the invention, the anti-surge capability of the driving circuit can be effectively improved.

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Description

Technical Field

[0001] The present invention relates to the technical field of power electronics, and in particular to a power tube boost driving circuit. Background Art

[0002] In traditional power supply systems, especially in high-voltage power supply applications, NMOS transistors are often used for power conversion and control. However, due to the high voltage in the power supply system, if a reverse voltage appears in the circuit, the body diode of the NMOS may be turned on, causing current to flow through the body diode, which may damage the previous circuit. The forward connection of the NMOS is difficult to meet the reverse connection protection requirements in the high-voltage power supply system. Summary of the invention

[0003] In view of the above problems existing in the prior art, the present invention proposes a power tube boost driving circuit, which mainly solves the problem that the existing driving circuit has reverse voltage, which easily causes damage to the previous stage circuit.

[0004] In order to achieve the above purpose and other purposes, the technical solution adopted by the present invention is as follows.

[0005] The present application provides a power tube boost driving circuit, comprising: a power supply module, which is used to provide a high voltage input; an isolation driving module, which is powered by the power supply module and generates a pulse control signal; a boost module, which performs a boost switching operation based on the pulse control signal; a power tube, which is connected to the output end of the boost module to conduct the boosted voltage to a load; and a sampling module, which samples the output end of the boost module and feeds back the sampled voltage to the isolation driving module, so that the isolation driving module adjusts the pulse control signal based on the sampled voltage.

[0006] In one embodiment of the present application, the boost module includes a switching tube, an inductor, a freewheeling diode and a first capacitor, the gate of the switching tube is connected to the pulse control signal, the source is connected to the signal ground, and the drain is respectively connected to the first end of the inductor and the anode of the freewheeling diode; the second end of the inductor is connected to the output end of the power supply module, the cathode of the freewheeling diode is connected to the first end of the first capacitor, and the second end of the first capacitor is connected to the second end of the inductor.

[0007] In one embodiment of the present application, a current limiting resistor is further arranged between the power supply module and the isolation driving module, one end of the current limiting resistor is connected to the power supply end of the isolation driving module, and the other end is connected to the positive output end of the power supply module, and the negative output end of the power supply module is connected to the signal ground.

[0008] In an embodiment of the present application, the connection end between the current limiting resistor and the isolation driving module is further connected to a signal ground via a fourth resistor.

[0009] In an embodiment of the present application, the sampling module includes a first sampling resistor and a second sampling resistor connected in series, and a connection point between the first resistor and the second resistor is connected to a feedback end of the isolation driving module as a sampling point.

[0010] In one embodiment of the present application, the power tube is an NMOS transistor, the source of the power tube is connected to the second end of the first capacitor, the gate is connected to the first end of the first capacitor, and the drain is connected to the load.

[0011] In one embodiment of the present application, the power supply output voltage is 270V.

[0012] In an embodiment of the present application, the switch tube is an NMOS transistor, the positive electrode of the isolation driving module is connected to the gate of the switch tube, and the negative electrode is connected to the signal ground.

[0013] In one embodiment of the present application, a voltage stabilizing diode is further provided at the output end of the boost module, and the voltage stabilizing diode is used to stabilize the power tube.

[0014] In one embodiment of the present application, the load includes a load resistor and a second capacitor, the first end of the second capacitor is connected to the first end of the load resistor and connected to the drain of the power tube, and the second end of the second capacitor is connected to the second end of the load resistor and connected to the signal ground.

[0015] As described above, the power tube boost driving circuit provided in the present application has the following beneficial effects.

[0016] The present application controls the boost process through a pulse control signal and samples the boost output. The pulse control signal is adjusted based on the sampled voltage, which can effectively prevent overvoltage. The PWM pulse is given to the switch tube of the boost module, and a suitable inductance is provided to enable the external NMOS to achieve a suitable turn-on time, increase the efficiency of the circuit and prevent turn-on surges. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 Schematic diagram of the circuit structure of a power tube boost driving circuit in one embodiment of the present application.

[0018] Description of labels:

[0019] R1-first sampling resistor; R2-second sampling resistor; R3-current limiting resistor; R4-fourth resistor; L-inductor; C1-first capacitor; C2-second capacitor; M1-switch tube; M2-power tube, D1-freewheeling diode, D2-voltage regulator diode. DETAILED DESCRIPTION

[0020] The following describes the embodiments of the present invention by specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the following embodiments and features in the embodiments can be combined with each other without conflict.

[0021] It should be noted that the illustrations provided in the following embodiments are only schematic illustrations of the basic concept of the present invention, and thus the drawings only show components related to the present invention rather than being drawn according to the number, shape and size of components in actual implementation. In actual implementation, the type, quantity and proportion of each component may be changed arbitrarily, and the component layout may also be more complicated.

[0022] The inventors have found that:

[0023] In traditional power supply systems, especially in high-voltage power supply application scenarios, NMOS transistors are often used for power conversion and control. However, due to the high voltage in the power supply system, if a reverse voltage appears in the circuit, the body diode of the NMOS may be turned on, causing current to flow through the body diode, which may damage the previous circuit, and the positive connection method of the NMOS is difficult to cope with the reverse connection protection requirements in the high-voltage power supply system. Therefore, it is of great practical significance to design a circuit solution that can drive the NMOS under high voltage conditions and prevent reverse connection damage. The present invention relates to a high-voltage drive NMOS and an anti-reverse connection circuit using a boost topology, including a pwm isolation drive module, a BOOST circuit, a power supply system, and an NMOS circuit based on boost circuit control, a driver IC power supply circuit, an imitation backflow system, and a sampling circuit.

[0024] When the MOS channel of the power tube is not open, the current flows to the load through the body diode. When the channel is open, the current flows through the line and changes. The voltage is collected by the sampling resistor to coordinate the pulse width state of the previous PWM waveform. This idea can not only suppress the surge current when the NMOS is turned on, reduce the transmission loss, but also realize the function of circuit reverse connection. Compared with the traditional existing reverse connection protection circuit, it has the characteristics of autonomy, simplicity, low heat generation, etc., which can greatly improve the stability and reliability of the power supply system.

[0025] See also Figure 1 , Figure 1The circuit structure diagram of the boost drive circuit in one embodiment of the present application. The power tube boost drive circuit provided in the present application includes: a power supply module, which is used to provide a high voltage input; an isolation drive module, which is powered by the power supply module and generates a pulse control signal; a boost module, which performs a switching operation of the boost based on the pulse control signal; a power tube M2, which is connected to the output end of the boost module to conduct the boosted voltage to the load; a sampling module, which samples the output end of the boost module and feeds back the sampled voltage to the isolation drive module, so that the isolation drive module adjusts the pulse control signal based on the sampled voltage.

[0026] In one embodiment, the boost module includes a switch tube M1, an inductor L, a freewheeling diode D1 and a first capacitor C1, the gate of the switch tube M1 is connected to the pulse control signal, the source is connected to the signal ground, and the drain is respectively connected to the first end of the inductor L and the anode of the freewheeling diode D1; the second end of the inductor L is connected to the output end of the power supply module, the cathode of the freewheeling diode D1 is connected to the first end of the first capacitor C1, and the second end of the first capacitor C1 is connected to the second end of the inductor L.

[0027] In one embodiment of the present application, a current limiting resistor R3 is further provided between the power supply module and the isolation driving module, one end of the current limiting resistor R3 is connected to the power supply end of the isolation driving module, and the other end is connected to the positive output end of the power supply module, and the negative output end of the power supply module is connected to the signal ground. Exemplarily, the isolation driving module may use a signal generator, and a pulse control signal is generated by the signal generator and outputted by the I / O port to the gate of the switch tube M1.

[0028] In an embodiment of the present application, the connection end between the current limiting resistor R3 and the isolation driving module is further connected to a signal ground via a fourth resistor R4.

[0029] In one embodiment, the sampling module includes a first sampling resistor R1 and a second sampling resistor R2 connected in series, and a connection point between the first sampling resistor R1 and the second sampling resistor R2 is connected to a feedback end of the isolation driving module as a sampling point.

[0030] In one embodiment, the power tube M2 is an NMOS transistor, a source of the power tube M2 is connected to the second end of the first capacitor C1, a gate is connected to the first end of the first capacitor C1, and a drain is connected to the load.

[0031] In one embodiment, the power supply output voltage is 270 V. Of course, the power supply voltage can also be set and adjusted according to actual application requirements, and there is no limitation here.

[0032] In one embodiment, the switch tube M1 is an NMOS transistor, the positive electrode of the isolation driving module is connected to the gate of the switch tube M1, and the negative electrode is connected to the signal ground.

[0033] In one embodiment, a voltage stabilizing diode D2 is further provided at the output end of the boost module, and the voltage stabilizing diode D2 is used to stabilize the power tube M2.

[0034] In one embodiment, the load includes a load resistor and a second capacitor C2, a first end of the second capacitor C2 is connected to the first end of the load resistor and connected to the drain of the power tube M2, and a second end of the second capacitor C2 is connected to the second end of the load resistor and connected to the signal ground.

[0035] Specifically, the switch tube M1 is turned off: at this stage, the PWM (i.e., pulse control signal) of the isolation drive module is not emitted, and the switch tube M1 is turned off. The switch tube M1 provides PWM waves through the driver chip of the isolation drive module. The power supply of the driver chip comes from the power supply voltage, and the current limiting resistor R3 is used to limit the current. The current goes through the inductor L, which stores energy. The current in the inductor L gradually increases. At the same time, the voltage across the inductor L decreases to the negative pole on the side close to the power supply 270V, and the positive pole on the side close to the anode of the freewheeling tube. The inductor L begins to discharge. At this time, the freewheeling diode D1 connected to the inductor L is turned on and flows to the gate G of the power tube M2. The G-level voltage gradually increases, and the GS voltage gradually increases. However, at this time, the GS voltage of the power tube M2 has not yet reached VTH (turn-on voltage threshold), and the channel fails to open. The current flows from the power supply to the source level of the power tube M2 through the body diode to the drain level, and then to the load.

[0036] Switch-on phase: In this phase, the isolation drive module sends out a PWM pulse, and the switch tube M1 is turned on. Current flows from the power supply to the inductor L and the power tube M2. The inductor L stores energy, and the current in the inductor L gradually increases, while the voltage across the inductor L increases. The current passes through the channel of the switch tube M1 to the negative electrode, and the Ciss of the MOS of the power tube M2 fails to charge, and the MOS channel is closed. When the power tube M2 is not turned on, if the D-pole voltage (drain) is lower than the S-pole voltage (source), that is, when the MOSFET is in a reverse biased state, the body diode will be turned on, and the current will flow from the S-pole to the D-pole. The current flows through the body diode through the power tube M2. At this time, the current flows through the load resistor Rload and charges the C2 capacitor.

[0037] VGS>Vth stage: After several switching stages, when the G-level voltage begins to rise and the VGS (gate-source voltage) of the MOS tube reaches or exceeds VTH (threshold voltage), the channel of the power tube M2 will begin to conduct. At this time, the current will mainly pass through the channel and no longer go through the body diode. Once the channel is formed, since the on-resistance RDS(on) of the channel is much smaller than the forward on-resistance of the body diode, the current will preferentially choose to pass through the channel because it is a low-impedance path. At this time, the body diode will be turned off and will hardly conduct electricity. The current flows to the load through the channel. If the switching frequency is high enough, neither the inductor L nor the first capacitor C1 will be fully discharged, and the output load voltage will always be higher than the input voltage source. That is, continuous conduction mode (CCM). The longer the PWM high level time (that is, the longer the switch tube M1 is turned on), the greater the voltage at the output terminal V_g. If the duty cycle (the switch on time relative to the total switching cycle) and the number of switches are properly controlled, the circuit can enable the NMOS to achieve higher power and realize the functions of surge suppression and reverse protection.

[0038] In actual process, the node voltage between the sampling resistors R1 and R2 is transmitted to the feedback terminal of the driver IC of the isolation driver module to adjust the driving PWM wave.

[0039] Based on the technical solution of the above embodiment of the present application, when the MOS channel of the power tube M2 is not opened, the current flows to the load through the body diode. When the channel is opened, the current flows through the line and changes, and the voltage is collected by the sampling resistor to coordinate the pulse width state of the previous PWM waveform emission. This idea can not only suppress the surge current when the NMOS is turned on, reduce the transmission loss, but also realize the circuit anti-reverse function. Compared with the traditional existing anti-reverse circuit, it has the characteristics of autonomy, simplicity, low heat generation, etc., which can greatly improve the stability and reliability of the power supply system.

[0040] The above embodiments are merely illustrative of the principles and effects of the present invention, and are not intended to limit the present invention. Anyone familiar with the art may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by a person of ordinary skill in the art without departing from the spirit and technical concept disclosed by the present invention shall still be covered by the claims of the present invention.

Claims

1. A power tube boost driving circuit, characterized in that: include: A power supply module, which is used to provide high voltage input; an isolation driving module, which is powered by the power supply module and generates a pulse control signal; A boost module, which performs a switching operation of boosting based on the pulse control signal; A power tube connected to the output end of the boost module to conduct the boosted voltage to the load; A sampling module samples the output end of the boost module and feeds back the sampled voltage to the isolation driving module, so that the isolation driving module adjusts the pulse control signal based on the sampled voltage.

2. The power tube boost driving circuit according to claim 1, characterized in that: The boost module includes a switch tube, an inductor, a freewheeling diode and a first capacitor. The gate of the switch tube is connected to the pulse control signal, the source is connected to the signal ground, and the drain is respectively connected to the first end of the inductor and the anode of the freewheeling diode; the second end of the inductor is connected to the output end of the power supply module, the cathode of the freewheeling diode is connected to the first end of the first capacitor, and the second end of the first capacitor is connected to the second end of the inductor.

3. The power tube boost driving circuit according to claim 1, characterized in that: A current limiting resistor is also arranged between the power supply module and the isolation driving module, one end of the current limiting resistor is connected to the power supply end of the isolation driving module, and the other end is connected to the positive output end of the power supply module, and the negative output end of the power supply module is connected to the signal ground.

4. The power tube boost driving circuit according to claim 3, characterized in that: The connection end between the current limiting resistor and the isolation driving module is also connected to a signal ground via a fourth resistor.

5. The power tube boost driving circuit according to claim 1, characterized in that: The sampling module includes a first sampling resistor and a second sampling resistor connected in series, and a connection point between the first sampling resistor and the second sampling resistor is connected to a feedback end of the isolation driving module as a sampling point.

6. The power tube boost driving circuit according to claim 3, characterized in that: The power tube is an NMOS transistor, a source of the power tube is connected to the second end of the first capacitor, a gate is connected to the first end of the first capacitor, and a drain is connected to the load.

7. The power voltage driving circuit according to claim 2, characterized in that: The power supply output voltage is 270V.

8. The power tube boost driving circuit according to claim 3, characterized in that: The switch tube adopts an NMOS transistor, the positive electrode of the isolation driving module is connected to the gate of the switch tube, and the negative electrode is connected to the signal ground.

9. The power tube boost driving circuit according to claim 3, characterized in that: The output end of the boost module is also provided with a voltage stabilizing diode, through which the power tube is stabilized.

10. The power tube boost driving circuit according to claim 6, characterized in that: The load includes a load resistor and a second capacitor, wherein a first end of the second capacitor is connected to a first end of the load resistor and connected to a drain of the power tube, and a second end of the second capacitor is connected to a second end of the load resistor and connected to a signal ground.