WO2022206450A1

WO2022206450A1 - Power transistor driver circuit and power transistor driving method

Info

Publication number: WO2022206450A1
Application number: PCT/CN2022/081995
Authority: WO
Inventors: 王文情; 陈强强
Original assignee: 比亚迪半导体股份有限公司
Priority date: 2021-03-29
Filing date: 2022-03-21
Publication date: 2022-10-06
Also published as: CN115133917A

Abstract

The present disclosure relates to a power transistor driver circuit and a power transistor driving method. The power transistor driver circuit comprises an input module, an output module, and a transformer connected between the two. The input module controls, on the basis of an input signal acquired, a primary end of the transformer to generate an alternating current; the output module receives a voltage signal of a secondary end of the transformer and controls, on the basis of the voltage signal received, the turning on or off of a power transistor. The input module comprises a control module and a current-limiting resistor module. The control module outputs a control signal on the basis of the magnitude of the voltage of a power supply. The current-limiting resistor module adjusts the magnitude of a current-limiting resistance in the input module on the basis of the control signal, thus allowing the current-limiting resistance to be increased as the voltage of the power supply increases.

Description

Power tube driving circuit and power tube driving method

This disclosure claims the priority of the Chinese patent application with the application number 202110335392.7 and the application title "Power tube drive circuit and power tube drive method" filed with the China Patent Office on March 29, 2021, the entire contents of which are incorporated herein by reference Public.

technical field

The present disclosure relates to the field of electronic circuits, and in particular, to a power tube driving circuit and a power tube driving method.

Background technique

In the ultra-high voltage power tube drive circuit, there is a problem that the power domains of the input part and the output part are different. Generally, the input ground is connected to the system ground, which is 0V; while the output ground is a floating ground, which is connected to the power tube, such as with insulation. The source of the gate bipolar transistor (Insulated Gate Bipolar Transistor, IGBT) is connected, the lowest is 0V, and the highest can reach several hundred volts or even more than one thousand volts. Therefore, it is necessary to isolate the input part and the output part, such as using a transformer to isolate the input part and the output part.

In high-integration applications, the input chip as the input part, the output chip as the output part, and the transformer used for isolation are packaged together. Implemented as a coupled coil, the inductance of the transformer is very small, generally only on the order of tens of nanofarads. In order to realize the transmission of the signal between the input part and the output part, the input part usually generates an alternating current signal on the transmitting end coil of the transformer, and the transformer transmits the signal to the receiving end through the signal coupling between the coils. The coil ensures that the output part connected to the receiving coil can receive the corresponding signal and make processing and response.

In order to ensure that the output part can correctly receive and identify the corresponding signal, the current provided by the input part to the transformer needs to be large enough. If the current is too small, the resonance amplitude on the transformer will be reduced, and the output part may not be able to identify the corresponding signal. .

SUMMARY OF THE INVENTION

The purpose of the present disclosure is to provide a power tube driving circuit and a power tube driving method that are reliable and consume less power.

In order to achieve the above object, the present disclosure provides a power tube drive circuit, the power tube drive circuit includes an input module, an output module and a transformer, the input module and the output module are connected through the transformer, and the input module is connected according to the The acquired input signal controls the primary end of the transformer to generate alternating current; the output module receives the voltage signal of the secondary end of the transformer, and controls the opening and closing of the power tube according to the received voltage signal.

Wherein, the input module includes:

a control module, the control module outputs a control signal according to the magnitude of the power supply voltage;

A current-limiting resistor module, which adjusts the size of the current-limiting resistor value in the input module according to the control signal, so that the current-limiting resistor value increases with the increase of the power supply voltage.

Optionally, the current limiting resistor module includes a first preset resistor, n parallel resistors and n parallel switch tubes, the n parallel resistors and the n parallel switch tubes are in one-to-one correspondence, and each parallel resistor After being connected in series with the corresponding parallel switch tube, it is connected in parallel with the first preset resistor, and the parallel resistor is the current limiting resistor in the input module.

The control signal includes n sub-signals, the n parallel switch tubes receive the n sub-signals in a one-to-one correspondence, and each parallel switch tube controls the on-off of the source and the drain according to the sub-signal received by the gate .

Optionally, the current limiting resistor module includes a first preset resistor, n series resistors and n series switch tubes, the n series resistors and the n series switch tubes are in one-to-one correspondence, and each series resistor In parallel with the corresponding series switch tube, the first preset resistor is connected in series with the n series resistors, and the series resistor is the current limiting resistor in the input module.

The control signal includes n sub-signals, the n series switch tubes receive the n sub-signals in a one-to-one correspondence, and each series switch tube controls the on-off of the source and the drain according to the sub-signal received by the gate .

Optionally, the current limiting resistor module includes a parallel part and a series part, the parallel part includes a first preset resistor, m mixed parallel resistors and m mixed parallel switch tubes, the m mixed parallel resistors and all The m hybrid parallel switch tubes are in one-to-one correspondence, and each hybrid parallel resistor is connected in series with the corresponding hybrid parallel switch tube and then in parallel with the first preset resistor.

The series part includes (n-m) hybrid series switch tubes and (n-m) hybrid series resistors connected in series, and the (n-m) hybrid series resistors correspond to the (n-m) hybrid series switch tubes in one-to-one correspondence. A mixed series resistor is connected in parallel with the corresponding mixed series switch.

The resistor connected in series with the parallel part and the series part is the current limiting resistor in the input module.

Wherein, the control signal includes n sub-signals, the m hybrid parallel switch tubes and the (n-m) hybrid series switch tubes receive the n sub-signals in a one-to-one correspondence, each hybrid parallel switch tube and each The hybrid series switch tube controls the on-off of the source and the drain according to the sub-signal received by the gate.

Optionally, the control module includes n voltage dividing resistors and n voltage dividing comparators, the n voltage dividing resistors are connected in series between the power supply and the ground wire, and the n voltage dividing resistors and the The n voltage divider comparators are in one-to-one correspondence, the first input terminal of each voltage divider comparator is input with a predetermined reference voltage, and the second input terminal of each voltage divider comparator is respectively connected to the same side of the corresponding voltage divider resistor .

Wherein, the n voltage dividing comparators output the n sub-signals respectively.

Optionally, the control module includes a first voltage dividing resistor, a second voltage dividing resistor, and n common voltage comparators, and the first voltage dividing resistor and the second voltage dividing resistor are connected in series with the power supply and the ground. Between the lines, the first input terminal of each common voltage comparator inputs n different reference voltages respectively, and the second input terminal of each common voltage comparator is connected to the first voltage dividing resistor and the second voltage dividing resistor. between the voltage divider resistors.

Wherein, the n common voltage comparators output the n sub-signals respectively.

Optionally, the control module includes a current source, a preset switch tube, and n signal generating sub-modules, the n signal generating sub-modules output the n sub-signals respectively, and each signal generating sub-module includes a first switch. tube, a second switch tube, a voltage drop generation module, a second preset resistor and a capacitor.

Wherein, the source of the preset switch, the source of the first switch and the source of the second switch are connected to a power supply, and the drain and gate of the preset switch pass the current Source ground line, the gate of the first switch is connected to the gate of the preset switch, the drain of the first switch is connected to the gate of the second switch, and the first switch is The drain of the second switch is connected to one end of the second preset resistor and one end of the capacitor through the ground wire of the voltage drop generation module, and the other end of the second preset resistor and The other end of the capacitor is grounded, and the drain of the second switch tube outputs the sub-signal.

Optionally, the voltage drop generation module includes a third switch tube and a fourth switch tube, the drain of the third switch tube is connected to the drain of the first switch tube, the third switch tube and the The fourth switch tubes are connected by a diode, and the source electrodes of the fourth switch tubes are grounded.

Optionally, the third switch transistor and the fourth switch transistor are MOS transistors or triodes.

Optionally, the voltage drop generating module is a resistor or a diode.

The present disclosure also provides a power tube driving method, which is applied to a power tube driving circuit. The power tube driving circuit includes an input module, an output module and a transformer. The input module and the output module are connected through the transformer. Methods include:

The input module controls the primary end of the transformer to generate an alternating current according to the acquired input signal, wherein a control signal is output according to the magnitude of the power supply voltage; the magnitude of the current-limiting resistance value in the input module is adjusted according to the control signal , so that the value of the current limiting resistor increases with the increase of the power supply voltage;

The output module receives the voltage signal of the secondary end of the transformer, and controls the opening and closing of the power tube according to the received voltage signal.

Through the above technical solution, the value of the current limiting resistor in the input module of the power tube driving circuit increases with the increase of the power supply voltage, so that when the power supply voltage is small, the value of the current limiting resistor is small to ensure that the driving current is large enough , to realize the effective transmission and reception of signals. As the power supply voltage increases, the current-limiting resistance also increases, which reduces the drive current, thereby reducing the power consumption of the chip.

Other features and advantages of the present disclosure will be described in detail in the detailed description that follows.

Description of drawings

The accompanying drawings are used to provide a further understanding of the present disclosure, and constitute a part of the specification, and together with the following detailed description, are used to explain the present disclosure, but not to limit the present disclosure. In the attached image:

1 is a schematic diagram of the basic principle of a power tube drive circuit in the related art;

2 is a schematic structural diagram of an input portion of a power tube drive circuit in the related art;

FIG. 3 is a schematic structural diagram of a power tube driving circuit according to an exemplary embodiment;

4 is a schematic structural diagram of an input module of a power tube driving circuit according to an exemplary embodiment;

5a is a schematic structural diagram of a current limiting resistor module according to an exemplary embodiment;

5b is a schematic structural diagram of a current limiting resistor module according to another exemplary embodiment;

5c is a schematic structural diagram of a current limiting resistor module according to another exemplary embodiment;

6a is a schematic structural diagram of a control module of an exemplary embodiment;

6b is a schematic structural diagram of a control module of another exemplary embodiment;

FIG. 6c is a schematic structural diagram of a control module of another exemplary embodiment;

7a-7c are schematic diagrams of waveforms when the control module of FIG. 6c is running;

FIG. 8 is a flowchart of a method for driving a power tube provided by an exemplary embodiment.

Detailed ways

The specific embodiments of the present disclosure will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are only used to illustrate and explain the present disclosure, but not to limit the present disclosure.

FIG. 1 is a schematic diagram of the basic principle of a power tube driving circuit in the related art. In the power tube driving circuit 100 of FIG. 1 , there is a problem that the power domains of the input part 101 and the output part 102 are different. The ground VSS1 of the input part 101 is connected to the system ground and is 0V; while the ground VSS2 of the output part 102 is floating The ground is connected to the source S of the power tube IGBT, the minimum is 0V, and the maximum can reach several hundred volts or even more than one thousand volts. The signal output by the output section 102 is connected to the gate G of the IGBT, and the drain D of the IGBT may be connected to a power source. An isolator 103 is provided between the input part 101 and the output part 102 to perform isolation processing. The isolator 103 can be a transformer, and here, the transformer can be any isolation device having a similar principle structure of a transformer.

In high-integration applications, the input part 101, the output part 102 and the transformer used as the isolator 103 are packaged together. In order to meet the requirements of small size, the used chip-level transformer is realized by making a coupling coil on a silicon chip. . The inductance of the transformer is very small. In order to realize the transmission of the signal between the input part 101 and the output part 102, usually the input part 101 transmits an alternating current signal to the sending end coil of the transformer, and the transformer passes through the sending end coil and the receiving end. The signal coupling between the coils transmits the signal to the output section 102 . In order to ensure that the output part 102 can correctly receive and recognize the signal, the current supplied by the input part 101 to the transformer needs to be large enough. If the current is too small, the resonant amplitude on the transformer will be reduced, and the output part 102 may not be able to recognize the signal. .

FIG. 2 is a schematic structural diagram of an input part of a power tube driving circuit in the related art. The input part 101 includes a drive control module and a fixed resistor Rg, the drive control module has a switch tube, and the switch tube and resistor Rg of the drive control module are connected between the power supply (VDD) and the ground to form a drive output circuit. The sending end coil is connected with the drive output circuit to form a transformer drive loop. The switch tube of the drive control module is used to make the transformer drive circuit generate alternating current signals under the control of the input signal, and the resistor Rg plays a role in limiting the current size of the transformer drive circuit. As shown in FIG. 2 , the drive control module may include a frequency generation module 1011 , an inverter Q1 , a NOT gate Q2 , a buffer Q3 , a first switch transistor Q4 , and a second switch transistor Q5 . The input part 101 receives the input signal and then passes through the inverter Q1 and then enters the NAND gate Q2. The signal generated by the frequency generating module 1011 is also input to the NAND gate Q2. The output of the NAND gate Q2 passes through the buffer Q3 and then enters the first switch tube Q4. The gate of the first switch transistor Q4 is connected to the power supply (VDD) through a fixed resistor Rg. The source of the first switch tube Q4 is connected to the drain of the second switch tube Q5, and is connected to one end of the transmitting end coil of the isolator. The gate of the second switch tube Q5 receives the above-mentioned input signal, and the source of the second switch tube Q5 The pole is connected to the other end of the sending end coil of the isolator, and is grounded. The above-mentioned fixed resistor Rg is used to limit the current, so as to avoid excessive current passing through the first switch tube Q4, resulting in excessive chip loss, and even causing local overheating and burning.

In the solution of FIG. 2 , the current-limiting resistance of the input part 101 of the power tube drive circuit is a fixed size, and the setting of the current-limiting resistance value needs to consider the full operating voltage range. When the supply voltage is low, the current-limiting resistor must be small enough to ensure that the drive current is large enough for the signal to be sent and received efficiently. In this case, when the power supply voltage is high, the corresponding driving current will be very large, which will greatly increase the power consumption of the chip. The inventor thought that the value of the current limiting resistor can be controlled to increase with the increase of the power supply voltage, so as to reduce the power consumption of the chip.

FIG. 3 is a schematic structural diagram of a power tube driving circuit according to an exemplary embodiment. As shown in FIG. 3 , the power tube driving circuit may include an input module 10 , an output module 20 and a transformer 30 , and the input module 10 and the output module 20 are connected through the transformer 30 . The input module 10 is used for controlling the primary side of the transformer 30 to generate alternating current according to the acquired input signal (eg, PWM signal). The output module 20 is used for receiving the voltage signal of the secondary end of the transformer 30 and controlling the opening and closing of the power tube according to the received voltage signal.

The input module 10 may include a control module 11 and a current limiting resistor module 12 .

The control module 11 is used for outputting a control signal according to the magnitude of the power supply voltage.

The current limiting resistor module 12 is used for adjusting the size of the current limiting resistor value in the input module 10 according to the control signal, so that the current limiting resistor value increases with the increase of the power supply voltage.

In the embodiment of FIG. 3 , the input module 10 includes not only the drive control module 13 , but also the control module 11 and the current limiting resistor module 12 . For the structure of the drive control module 13 , refer to the drive control module described above in conjunction with FIG. 2 . This will not be repeated here. The current limiting resistor module 12 is connected with the switch tube of the drive control module 13 and the sending end coil of the transformer 30 to form a transformer drive circuit. The input module 10 obtains the input signal through the drive control module 13, and the drive control module 13 controls its switch tube according to the obtained input signal, thereby making the transformer drive circuit generate an alternating current signal.

The current limiting resistor module 12 is connected to the transformer drive circuit of the input module 10. The current limiting resistor module 12 is equivalent to a current limiting resistor with an adjustable resistance value. The current limiting resistor module 12 can adjust its own resistance under the action of the control signal. value, and then adjust the current-limiting resistance value of the transformer drive loop in the input module 10 to change the drive current in the transformer drive loop.

In this way, when the power supply voltage is small, the value of the current limiting resistor is small to ensure that the driving current is large enough to realize the effective transmission and reception of signals. As the power supply voltage increases, the current-limiting resistance also increases, which reduces the drive current, thereby reducing the power consumption of the chip.

FIG. 4 is a schematic structural diagram of an input module of a power tube driving circuit according to an exemplary embodiment. As shown in FIG. 4 , on the basis of FIG. 2 , the current limiting resistor in the input module is replaced by a fixed resistor Rg with a control module 11 and a current limiting resistor module 12 . The control module 11 is connected between the power supply and the ground wire, and the current limiting resistor module 12 is connected between the power supply and the drain of the first switch transistor Q4. The resistance between R+ and R- at both ends of the current limiting resistor module 12 is an adjustable current limiting resistor, and its resistance value is controlled by the control module 11 . The control module 11 controls the resistance value of the current limiting resistor module 12 according to the magnitude of the power supply voltage, so that the resistance value (current limiting resistance value) increases with the increase of the power supply voltage.

The current limiting resistor module 12 may be composed of resistors connected in series and/or in parallel, wherein the parallel connection is shown in Figure 5a, the series connection is shown in Figure 5b, and the series and parallel combination is shown in Figure 5c.

The current-limiting resistance module 12 may include a switch tube for controlling whether its adjustable resistance can be connected to the transformer drive circuit, and the adjustable resistance may include a series resistance connected by a series structure and/or a parallel resistance connected by a parallel structure . Correspondingly, the current limiting resistor module 12 may include a switch tube connected in parallel with the series resistor, and/or a switch tube connected in series with the parallel resistor, so that the switch tube can control whether the corresponding resistance can be controlled under the action of the control signal. Connect to the transformer drive circuit.

In addition, the current limiting resistor module 12 may also include a preset resistor, which is connected in series or in parallel with the adjustable resistor, the preset resistor is often connected in the transformer drive circuit, and the adjustable resistor can be used in the control of the control signal. Connect or not connect to the drive circuit of the transformer.

FIG. 5a is a schematic structural diagram of the current limiting resistor module 12 according to an exemplary embodiment. As shown in FIG. 5a, the current limiting resistor module 12 may include a first preset resistor R0, n parallel resistors R11-R1n, and n parallel switch tubes PM11-PM1n, and the n parallel resistors correspond to the n parallel switch tubes one-to-one , each parallel resistor is connected in series with the corresponding parallel switch tube and then connected in parallel with the first preset resistor R0 , and the parallel resistor is the current limiting resistor in the input module 10 .

That is, the first parallel resistor R11 and the corresponding parallel switch tube PM11 are connected in series with the first preset resistor R0, and the second parallel resistor R12 and the corresponding parallel switch tube PM12 are connected in series with the first preset resistor. R0 is connected in parallel, ..., the nth parallel resistor R1n is connected in series with the corresponding parallel switch PM1n and then connected in parallel with the first preset resistor R0.

The series connection of the parallel resistor and the corresponding parallel switch tube means that the drain and source of the parallel switch tube are used as two ends in series with the parallel resistor, as shown in Figure 5a. That is, the source of the parallel switch is connected to one end of the first preset resistor R0, and the drain of the parallel switch is connected to the other end of the first preset resistor R0 through the corresponding parallel resistor.

In this embodiment, the control signal includes n sub-signals, where n is an integer greater than or equal to 1. The n parallel switch tubes receive n sub-signals in a one-to-one correspondence, and each parallel switch tube is used to control the on-off of the source electrode and the drain electrode according to the sub-signal received by the gate. The sub-signals received by the n parallel switch tubes PM11-PM1n are Ct1-Ctn respectively.

In Fig. 5a, the first preset resistor R0 is directly connected to the transformer drive circuit, and the n parallel resistors R11-R1n are controlled by the n parallel-connected switch tubes PM11-PM1n, respectively. In Fig. 5a, a PMOS device is used as the switch tube. When the sub-signal is "0", the corresponding parallel resistor is connected to the loop, thereby reducing the resistance value of the current limiting resistor module 12; when the sub-signal is "1", the The corresponding parallel branch is disconnected, and the corresponding parallel resistor is not connected to the loop, thereby increasing the resistance value of the current limiting resistor module 12 .

FIG. 5b is a schematic structural diagram of the current limiting resistor module 12 according to another exemplary embodiment. As shown in FIG. 5b, the current limiting resistor module 12 may include a first preset resistor R0, n series resistors R21-R2n, and n series switch tubes PM21-PM2n. The n series resistors are in one-to-one correspondence with the n series switch tubes, each series resistor is connected in parallel with the corresponding series switch tube, the first preset resistor R0 is connected in series with the n series resistors, and the series resistance is the input module 10 current limiting resistor.

That is, the first series resistor R21 is connected in parallel with the corresponding series switch tube PM21, the second series resistor R22 is connected in parallel with the corresponding series switch tube PM22, ..., the nth series resistor R2n is connected in parallel with the corresponding series switch tube PM2n. .

Wherein, the control signal includes n sub-signals, n series switch tubes receive n sub-signals in one-to-one correspondence, and each series switch tube is used to control the on-off of the source and the drain according to the sub-signal received by the gate.

In FIG. 5b, the first preset resistor R0 is directly connected to the transformer driving circuit, and the n series resistors R21-R2n are respectively controlled by the n series-connected switch tubes PM21-PM2n. In Fig. 5b, a PMOS device is used as the switch tube. When the sub-signal is "1", the corresponding series resistance is connected to the loop, thereby increasing the resistance value of the current limiting resistor module 12; when the sub-signal is "0", the The corresponding series resistance is short-circuited, that is, the corresponding series resistance is not connected in the loop, thereby reducing the resistance value of the current limiting resistance module 12 .

In the control module 11, a comparator can be used to determine the magnitude of the power supply voltage, thereby generating sub-signals Ct1-Ctn.

FIG. 5c is a schematic structural diagram of the current limiting resistor module 12 according to another exemplary embodiment. As shown in FIG. 5c, the current limiting resistor module 12 may include a parallel part and a series part. The parallel part may include a first preset resistor R0, m mixed parallel resistors R31-R3m, and m mixed parallel switch tubes PM31-PM3m. The m hybrid parallel resistors are in one-to-one correspondence with the m hybrid parallel switch tubes, and each hybrid parallel resistor is connected in series with the corresponding hybrid parallel switch tube and then in parallel with the first preset resistor R0.

The series part may include (n-m) mixed series switching transistors PM3(m+1)-PM3n and (n-m) mixed series resistors R3(m+1)-R3n connected in series. The (n-m) mixed series resistors are in one-to-one correspondence with the (n-m) mixed series switch tubes, and each mixed series resistor is connected in parallel with the corresponding mixed series switch tubes.

The resistor connected in series with the parallel part and the series part is the current limiting resistor in the input module 10 .

Wherein, the control signal includes n sub-signals, m hybrid parallel switch tubes and (n-m) hybrid series switch tubes receive n sub-signals in one-to-one correspondence, each hybrid parallel switch tube and each hybrid series switch tube are used according to the gate The received sub-signal controls the on and off of the source and drain. m is an integer less than n.

In FIG. 5c, the first preset resistor R0 is directly connected to the transformer drive circuit, and the m hybrid parallel resistors R31-R3m are respectively controlled by the m hybrid parallel switch tubes PM31-PM3m. (n-m) mixed series resistors R3(m+1)-R3n are controlled by (n-m) mixed series-connected switching transistors PM3(m+1)-PM3n respectively.

In Figure 5c, the PMOS device is also used as the switch tube. When the sub-signal is "0", the corresponding mixed parallel resistance is connected to the loop, or the corresponding mixed series resistance is not connected to the loop because it is short-circuited, thereby limiting the current. The resistance value of the resistance module 12 changes; when the sub-signal is "1", the corresponding mixed parallel resistance is not connected to the loop, or the corresponding mixed series resistance is connected to the loop, thereby changing the resistance value of the current limiting resistance module 12 .

FIG. 6a is a schematic structural diagram of the control module 11 of an exemplary embodiment. As shown in FIG. 6a, the control module 11 includes n voltage dividing resistors RA1-RAn and n voltage dividing comparators P11-P1n. The n voltage dividing resistors are connected in series between the power supply and the ground wire, and the n voltage dividing resistors are in one-to-one correspondence with the n voltage dividing comparators. The first input terminal (inverting input terminal -) of each voltage dividing comparator is input with a predetermined reference voltage VREF, and the second input terminal (non-inverting input terminal +) of each voltage dividing comparator is respectively connected to the corresponding voltage dividing the same side of the resistor. The n voltage divider comparators output n sub-signals Ct1 to Ctn respectively.

Among them, the voltage dividing resistor has two sides, one side is close to the power supply, and the other side is close to the ground wire. The second input terminal (+) of each voltage divider comparator is connected to the side of the corresponding voltage divider resistor close to the power supply, or is connected to the side of the corresponding voltage divider resistor close to the ground line.

In FIG. 6a, the first input terminal (-) of each voltage divider is connected to the reference voltage VREF, and the second input terminal (+) is connected to the resistance voltage division sampling terminal of the power supply. N voltage divider resistors are connected in series to form a voltage divider circuit. Taking the generation process of the control signal Ct1 in Fig. 6a as an example, when the power supply voltage VDD is high enough and VREF<VF1, the sub-signal Ct1 generated at this time is "1" and is output to the current limiting resistor module 12. The sub-signal in Fig. 5a The parallel resistance corresponding to Ct1 is disconnected;

As the power supply voltage VDD decreases, when VF1<VREF, the generated sub-signal Ct1 is "0" and is output to the current limiting resistor module 12. In Fig. 5a, the parallel resistance corresponding to the sub-signal Ct1 is in the connected state, which reduces the The equivalent impedance on the drive loop reduces the resistance value of the current limiting resistor module 12, thereby increasing the transformer drive current that can be provided under the corresponding power supply voltage.

The generation principle of the sub-signals Ct2-Ctn is similar to that of Ct1, and the inversion point of the voltage divider comparators P11-P1n can be realized by adjusting the input reference or adjusting the voltage-dividing resistance ratio of the power supply. In Figure 6a, multiple comparators correspond to the same reference voltage and different sampling inputs.

FIG. 6b is a schematic structural diagram of the control module 11 of another exemplary embodiment. In Figure 6b, multiple comparators correspond to the same sampling input and different reference voltages. As shown in FIG. 6b, the control module 11 includes a first voltage dividing resistor RB1, a second voltage dividing resistor RB2, and n common voltage comparators P21-P2n. The first voltage dividing resistor and the second voltage dividing resistor are connected in series between the power supply and the ground wire to form a voltage dividing circuit. The first input terminal (inverting input terminal-) of each common voltage comparator inputs n different reference voltages VREF1 to VREFn respectively, and the second input terminal (non-inverting input terminal +) of each common voltage comparator is connected to between the first voltage dividing resistor and the second voltage dividing resistor. The voltage dividing resistor between the first voltage dividing resistor and the second voltage dividing resistor is VF. The n common voltage comparators respectively output n sub-signals Ct1 to Ctn. FIG. 6c is a schematic structural diagram of a control module of another exemplary embodiment. As shown in Fig. 6c, the control module 11 includes a current source I0, a preset switch tube PM0, and n signal generating sub-modules 111-11n. The n signal generating sub-modules output n sub-signals Ct1-Ctn respectively, and each signal generating sub-module outputs n sub-signals Ct1-Ctn respectively. The module includes a first switch tube PMa, a second switch tube PMb, a voltage drop generation module, a second preset resistor RC and a capacitor C0.

The source of the preset switch PM0, the source of the first switch PMa and the source of the second switch PMb are connected to the power supply, the drain and gate of the preset switch PM0 are connected to the grounding line of the current source, and the first The gate of the switch tube PMa is connected to the gate of the preset switch tube PM0, the drain of the first switch tube PMa is connected to the gate of the second switch tube PMb, and the drain of the first switch tube PMa generates a module grounding line through a voltage drop, The drain of the second switch tube PMb is connected to one end of the second preset resistor RC and one end of the capacitor C0, the other end of the second preset resistor RC and the other end of the capacitor C0 are grounded, and the drain of the second switch tube PMb outputs sub-signal.

The voltage drop generation module in FIG. 6c includes a third switch NM1 and a fourth switch NM2. The drain of the third switch NM1 is connected to the drain of the first switch PMa, the third switch NM1 and the fourth switch NM2 are connected by a diode, and the source of the fourth switch NM2 is grounded.

The third switch transistor NM1 and the fourth switch transistor NM2 may be MOS transistors or triodes. The third switch transistor NM1 and the fourth switch transistor NM2 in FIG. 6c are N-type MOS transistors.

7a-7c are schematic diagrams of waveforms when the control module 11 of FIG. 6c operates. The current source I0 produces a voltage drop across the third switch tube NM1 and the fourth switch tube NM2, and the voltage is VNET0. When the power supply voltage VDD is high enough to keep I0 constant, VNET0 will also be fixed. As the power supply voltage VDD decreases, when When it is close to VNET0, the current I1 cannot be maintained and decreases, and accordingly, VNET0 will also decrease accordingly, and basically follow the power supply voltage VDD, as shown in Figure 7a.

The difference between the power supply voltage VDD and VNET0 is V1=VDD-VNET0. The magnitude of V1 will control the conduction of the second switch tube PMb, and then control the output current I2 of the second switch tube PMb. The magnitude of the current I2 is mainly determined by the first The device size (current) of the two-switch PMb is determined by the size of V1, and is in a proportional relationship. On the premise that the size of the second switch tube PMb is given, there is I2=K*V1, where K is the relevant current generation coefficient, which is related to the working state of the device. The maximum value of I2 is limited by the power supply voltage VDD/R1, and R1 is the resistance value of the second preset resistor RC.

That is, when K*V1>VDD/R1, I2=VDD/R1; when K*V1<=VDD/R1, I2=K*V1. The output signal Ct1 of the control module 11 is the voltage drop I2*R1 generated by I2 on the second preset resistor RC, as shown in FIG. 7b and FIG. 7c.

When the power supply voltage is high enough, the output Ct1 signal will be close to the power supply voltage VDD, the corresponding switch in the current limiting resistor module 12 is turned off, and the corresponding parallel resistor in FIG. 5a is disconnected from the driving loop.

As the power supply voltage VDD gradually decreases, V1 will decrease. When K*V1≤VDD/R1, the current I2 will gradually decrease from VDD/R1, and further, the Ct1 voltage will also decrease from the power supply voltage VDD, and gradually Turn on the corresponding switch tube in the current limiting resistor module 12 until it is completely turned on, and the parallel resistor in FIG. When the power supply voltage VDD drops to the point where the second switch tube PMb is turned off, at this time I2 = 0, the output of Ct1 will be pulled down to the "0" level by R1, as shown in Figure 7c.

The thresholds of the access control signals (sub-signals Ct1 to Ctn) of the resistors in the current limiting resistor module 12 are mainly determined by the current source I0 and the dimensions of the third switch NM1 and the fourth switch NM2, wherein the current source I0 is determined by the size of the third switch NM1 and the fourth switch NM2. The size of the first switch tube PMa is controlled.

In addition to the MOS transistor, the voltage drop generation module can also be a resistor or a diode.

The present disclosure also provides a power tube driving method applied to a power tube driving circuit. The power tube driving circuit includes an input module 10 , an output module 20 and a transformer 30 , and the input module 10 and the output module 20 are connected through the transformer 30 . FIG. 8 is a flowchart of a method for driving a power tube provided by an exemplary embodiment. As shown in Figure 8, the method may include:

Step S101, the input module 10 controls the primary end of the transformer 30 to generate an alternating current according to the acquired input signal. The control signal is output according to the magnitude of the power supply voltage, and the value of the current limiting resistor in the input module 10 is adjusted according to the control signal, so that the current limiting resistor value increases with the increase of the power supply voltage.

Step S102, the output module 20 receives the voltage signal of the secondary end of the transformer 30, and controls the opening and closing of the power tube according to the received voltage signal.

The preferred embodiments of the present disclosure have been described above in detail with reference to the accompanying drawings. However, the present disclosure is not limited to the specific details of the above-mentioned embodiments. Various simple modifications can be made to the technical solutions of the present disclosure within the scope of the technical concept of the present disclosure. These simple modifications all fall within the protection scope of the present disclosure.

In addition, it should be noted that each specific technical feature described in the above-mentioned specific implementation manner may be combined in any suitable manner under the circumstance that there is no contradiction. In order to avoid unnecessary repetition, various possible combinations are not described in the present disclosure.

In addition, the various embodiments of the present disclosure can also be arbitrarily combined, as long as they do not violate the spirit of the present disclosure, they should also be regarded as the contents disclosed in the present disclosure.

Claims

A power tube drive circuit, characterized in that the power tube drive circuit comprises an input module (10), an output module (20) and a transformer (30), the input module (10) and the output module (20) Connected through the transformer (30), the input module (10) controls the primary end of the transformer (30) to generate alternating current according to the acquired input signal; the output module (20) receives the transformer (30) ) of the secondary side of the voltage signal, and control the opening and closing of the power tube according to the received voltage signal,

Wherein, the input module (10) includes:

a control module (11), the control module (11) outputs a control signal according to the magnitude of the power supply voltage;

A current-limiting resistance module (12), the current-limiting resistance module (12) adjusts the size of the current-limiting resistance value in the input module (10) according to the control signal, so that the current-limiting resistance value follows the increases as the power supply voltage increases.
The power tube driving circuit according to claim 1, wherein the current limiting resistor module (12) comprises a first preset resistor (R0), n parallel resistors (R11-R1n) and n parallel switch tubes (PM11-PM1n), the n parallel resistors are in one-to-one correspondence with the n parallel switch tubes, and each parallel resistor is connected in series with the corresponding parallel switch tube and then connected in parallel with the first preset resistor (R0), The resistors connected in parallel are the current limiting resistors in the input module (10),

The control signal includes n sub-signals, the n parallel switch tubes receive the n sub-signals in a one-to-one correspondence, and each parallel switch tube controls the on-off of the source and the drain according to the sub-signal received by the gate .
The power tube driving circuit according to claim 1, wherein the current limiting resistor module (12) comprises a first preset resistor (R0), n series resistors (R21-R2n) and n series switch tubes (PM21-PM2n), the n series resistors are in one-to-one correspondence with the n series switch tubes, each series resistor is connected in parallel with the corresponding series switch tube, and the first preset resistor is connected to the n series resistors connected in series, the resistance after the series connection is the current limiting resistance in the input module (10),

The control signal includes n sub-signals, the n series switch tubes receive the n sub-signals in a one-to-one correspondence, and each series switch tube controls the on-off of the source and the drain according to the sub-signal received by the gate .
The power tube driving circuit according to claim 1, characterized in that, the current limiting resistor module (12) comprises a parallel part and a series part, and the parallel part comprises a first preset resistor (R0), m mixed parallel connections Resistors (R31 to R3m) and m hybrid parallel switch tubes (PM31 to PM3m), the m hybrid parallel resistors are in one-to-one correspondence with the m hybrid parallel switch tubes, and each hybrid parallel resistor corresponds to a corresponding hybrid parallel switch After the tube is connected in series, it is connected in parallel with the first preset resistor (R0),

The series part includes (n-m) mixed series switch tubes (PM3(m+1)～PM3n) and (n-m) mixed series resistors (R3(m+1)～R3n) connected in series, the (n-m) The mixed series resistors are in one-to-one correspondence with the (n-m) mixed series switch tubes, and each mixed series resistor is connected in parallel with the corresponding mixed series switch tubes.

The resistor connected in series with the parallel part and the series part is the current limiting resistor in the input module (10),

Wherein, the control signal includes n sub-signals, the m hybrid parallel switch tubes and the (n-m) hybrid series switch tubes receive the n sub-signals in a one-to-one correspondence, each hybrid parallel switch tube and each The hybrid series switch tube controls the on-off of the source and the drain according to the sub-signal received by the gate.
The power tube driving circuit according to any one of claims 2-4, characterized in that, the control module (11) comprises n voltage dividing resistors (RA1-RAn) and n voltage dividing comparators (P11) ~P1n), the n voltage dividing resistors are connected in series between the power supply and the ground wire, and the n voltage dividing resistors are in one-to-one correspondence with the n voltage dividing comparators. A predetermined reference voltage (VREF) is input to one input terminal, and the second input terminal of each voltage divider comparator is respectively connected to the same side of the corresponding voltage divider resistor,

Wherein, the n voltage dividing comparators output the n sub-signals respectively.
The power tube drive circuit according to any one of claims 2 to 4, wherein the control module (11) comprises a first voltage dividing resistor (RB1), a second voltage dividing resistor (RB2), n Common voltage comparators (P21-P2n), the first voltage divider resistor and the second voltage divider resistor are connected in series between the power supply and the ground wire, and the first input terminal of each common voltage comparator is respectively input There are n different reference voltages (VREF1-VREFn), the second input terminal of each common voltage comparator is connected between the first voltage dividing resistor and the second voltage dividing resistor,

Wherein, the n common voltage comparators output the n sub-signals respectively.
The power tube driving circuit according to any one of claims 2-4, wherein the control module (11) comprises a current source (I0), a preset switch tube (PM0) and n signal generators Modules (111-11n), the n signal generating sub-modules output the n sub-signals respectively, and each signal generating sub-module includes a first switch tube (PMa), a second switch tube (PMb), and a voltage drop generation module , the second preset resistor (RC) and capacitor (C0),

Wherein, the source of the preset switch, the source of the first switch and the source of the second switch are connected to a power supply, and the drain and gate of the preset switch pass the current source grounding line, the gate of the first switch is connected to the gate of the preset switch, the drain of the first switch is connected to the gate of the second switch, and the first switch is The drain of the second switch is connected to one end of the second preset resistor and one end of the capacitor through the ground wire of the voltage drop generation module, and the other end of the second preset resistor and The other end of the capacitor is grounded, and the drain of the second switch tube outputs the sub-signal.
The power tube driving circuit according to claim 7, wherein the voltage drop generation module comprises a third switch tube (NM1) and a fourth switch tube (NM2), and the drain of the third switch tube is connected to the The drain of the first switch tube, the diode connection between the third switch tube and the fourth switch tube, and the source of the fourth switch tube is grounded.
The power transistor driving circuit according to claim 8, wherein the third switch transistor and the fourth switch transistor are MOS transistors or triodes.
The power tube driving circuit according to claim 7, wherein the voltage drop generating module is a resistor or a diode.
A power tube driving method, applied to a power tube driving circuit, characterized in that the power tube driving circuit comprises an input module (10), an output module (20) and a transformer (30), the input module (10) and The output module (20) is connected through the transformer (30), and the method includes:

The input module (10) controls the primary end of the transformer (30) to generate an alternating current according to the acquired input signal, wherein a control signal is output according to the magnitude of the power supply voltage, and the input module is adjusted according to the control signal (10) The size of the current-limiting resistance value, so that the current-limiting resistance value increases with the increase of the power supply voltage;

The output module (20) receives the voltage signal of the secondary end of the transformer (30), and controls the opening and closing of the power tube according to the received voltage signal.