Switching tube driving control method and switching tube driving control structure

Abstract

The invention relates to a switching tube driving control method and a switching tube driving control structure, a control chip is used for acquiring and judging the state of a load connected with a switching tube, then a control signal is sent to a driving auxiliary power supply according to the state of the load, and the driving auxiliary power supply adjusts the output voltage thereof according to the control signal. The output voltage of the driving auxiliary power supply is input into the power supply input end of the driving chip, the control input end of the driving chip is connected with the control chip, the signal output end of the driving chip is connected with the control electrode of the switching tube, and the output signal of the driving chip serves as the driving signal of the switching tube. When the load state is a heavy load state, the output voltage of the driving auxiliary power supply is controlled to be increased, so that the high-level voltage of the driving signal of the switching tube is increased; and when the load state is a light load state, the output voltage of the driving auxiliary power supply is controlled to be reduced, so that the high-level voltage of the driving signal of the switching tube is reduced. According to the invention, the switching loss can be reduced while the working reliability and stability of the switching tube are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of power device driving, and in particular to a switch tube driving control method and a switch tube driving control structure. Background Art

[0002] In the scenarios of new energy photovoltaic, energy storage, and charging, high-efficiency conversion circuits are required, such as converters, to convert the DC power of solar panels into AC power for grid connection, as well as the bidirectional conversion of DC power of energy storage batteries or automotive power batteries with AC power of the grid. In the topological schemes of various conversion circuits, the efficiency curve is a key indicator that reflects the competitiveness of the product. However, semiconductor switch tubes, such as silicon MOS tubes, cannot have both small on-resistance (such as small Rds_on) and fast switching speed indicators (such as small Qg): if a MOS tube with a small on-resistance is selected, its switching speed will be slow, resulting in increased switching losses; if a MOS tube with a fast switching speed is selected, its on-resistance will be large, resulting in increased conduction losses. At present, the conduction loss of the converter under heavy load is mostly optimized by selecting MOS tubes, but it will cause its light-load switching loss to increase significantly, and it will be more obvious under variable frequency control (high light-load switching frequency), which is not conducive to the optimization of light-load efficiency.

[0003] Specifically, in general, the conduction loss of the switch tube dominates under heavy load conditions, and the switching loss of the switch tube dominates under light load conditions (under zero voltage soft switch design, the switching loss is mainly the turn-off loss). In view of this, the solution of the prior art is generally to reduce the conduction loss of heavy load by selecting a switch tube with a smaller on-resistance, and then reduce the impact of the slow switching speed of the switch tube by accelerating the shutdown circuit of the drive circuit or strengthening the current extraction capability of the drive chip, thereby reducing the overlap of voltage and current when the switch tube is turned off, and then reducing the turn-off loss. However, the reduction of the turn-off loss of the switch tube is limited, and it is impossible to optimize separately for heavy load and light load conditions. Generally speaking, although accelerating the shutdown of the switch tube improves the efficiency of light load conditions, it will increase the turn-off voltage spike of the switch tube under heavy load conditions, increase the voltage stress of the switch tube, and reduce the reliability of the switch tube.

[0004] Therefore, how to optimize the driving control of the switch tube so that it can adapt to different working conditions of light load or heavy load while ensuring the working reliability of the switch tube is the technical problem that this application aims to solve. Summary of the invention

[0005] A main purpose of the present invention is to overcome at least one of the above-mentioned defects, and to provide a switch tube drive control method and a switch tube drive control structure, which can drive the switch tube according to different working requirements under light load conditions and heavy load conditions to ensure the working reliability of the switch tube.

[0006] In order to achieve the above object, the technical solution adopted by the present invention is: The present invention provides a switch tube drive control method, which determines whether the load state connected to the switch tube is a light load state or a heavy load state, controls the output voltage of the driving auxiliary power supply according to the load state, and further controls the gate voltage of the switch tube, wherein: When the load state is a heavy load state, controlling the output voltage of the driving auxiliary power supply to increase, thereby increasing the high level voltage of the driving signal of the gate of the switching tube; When the load state is a light load state, the output voltage of the driving auxiliary power supply is controlled to decrease, thereby reducing the high level voltage of the driving signal of the gate of the switching tube.

[0007] According to one embodiment of the present invention, a first power threshold is preset, an output signal between the switch tube and the load is sampled and the load power is calculated accordingly, and the load power is compared with the first power threshold. If the load power is greater than the first power threshold, determining that the load state is a heavy load state; If the load power is not greater than the first power threshold, the load state is determined to be a light load state.

[0008] According to one embodiment of the present invention, a second power threshold and a third power threshold are preset, and the second power threshold is greater than the third power threshold. The output signal between the switch tube and the load is sampled and the load power is calculated accordingly, and the load power is compared with the second power threshold and the third power threshold. If the load power is not less than the second power threshold, determining that the load state is a heavy load state; If the load power is not greater than the third power threshold, the load state is determined to be a light load state.

[0009] In particular, the present invention also provides a switch tube drive control structure, which includes a control chip, a drive auxiliary power supply and a drive chip, wherein: The control chip samples the signal of the load connected to the switch tube, calculates and determines the load state according to the sampled signal, and then sends a control signal to the driving auxiliary power supply according to the load state. The driving auxiliary power supply adjusts its own output voltage according to the received control signal. The output voltage of the driving auxiliary power supply is input to the power supply input end of the driving chip. The control input end of the driving chip is connected to the control chip. The signal output end of the driving chip is connected to the control electrode of the switching tube. The output signal of the driving chip is used as the driving signal of the switching tube.

[0010] According to one embodiment of the present invention, the driving auxiliary power supply includes a first voltage-dividing resistor, a second voltage-dividing resistor, and a driving auxiliary power supply chip. The first voltage-dividing resistor and the second voltage-dividing resistor are connected in series to form a voltage-dividing circuit. The first end of the voltage-dividing circuit is connected to the output end of the driving auxiliary power supply, and the second end of the voltage-dividing circuit is grounded. The connection point between the first voltage-dividing resistor and the second voltage-dividing resistor is a voltage-dividing feedback point of the voltage-dividing circuit. The feedback control end of the driving auxiliary power supply chip is connected to the voltage-dividing feedback point. The driving auxiliary power supply chip performs closed-loop control on the voltage-dividing feedback point so that the voltage at the voltage-dividing feedback point is maintained at a fixed value Vref. The voltage-dividing feedback point is also connected to a regulation circuit. The regulation circuit connects the regulation resistor in the regulation circuit in parallel with the second voltage-dividing resistor according to a control signal sent by the control chip.

[0011] According to one embodiment of the present invention, the regulating circuit includes a first regulating resistor and a control switch, the first end of the first regulating resistor is connected to the voltage divider feedback point, the second end of the first regulating resistor is connected to the first signal pole of the control switch, the second signal pole of the control switch is grounded, the control pole of the control switch is connected to the IO output port of the control chip, the control switch is turned on when the IO output port of the control chip outputs a high level, and the first regulating resistor is connected in parallel with the second voltage divider resistor.

[0012] According to one embodiment of the present invention, the first voltage-dividing resistor is R61, the second voltage-dividing resistor is R62, and the first adjusting resistor is R63. When the IO output port of the control chip outputs a low level, the output voltage of the output end of the driving auxiliary power supply is Vref*(1+R61 / R62); When the IO output port of the control chip outputs a high level, the output voltage of the output end of the driving auxiliary power supply is Vref*(1+R61 / (R62 / / R63)).

[0013] According to one embodiment of the present invention, the regulation circuit includes a second regulation resistor, a third regulation resistor, a control switch, and a bypass capacitor. The first end of the second regulation resistor is connected to the voltage divider feedback point, the second end of the second regulation resistor is connected to the first end of the bypass capacitor and the first end of the third regulation resistor, the second end of the bypass capacitor is grounded, the second end of the third regulation resistor is connected to the first signal electrode of the control switch, the second signal electrode of the control switch is grounded, the control electrode of the control switch is connected to the PWM output port of the control chip, and when the PWM output port of the control chip outputs a PWM signal, the control switch is turned on at a time corresponding to the peak value of the PWM signal. When the control switch is turned on, the second regulation resistor is connected in series with the third regulation resistor and then in parallel with the second voltage divider resistor.

[0014] According to one embodiment of the present invention, the first voltage-dividing resistor is R71, the second voltage-dividing resistor is R72, the second regulating resistor is R73, the third regulating resistor is R74, and the duty cycle of the PWM signal is D. The output voltage of the output end of the driving auxiliary power supply is Vref[(1+R71 / R72)*(1-D)+(1+R71 / (R72 / / (R73+R74)))*D].

[0015] According to one embodiment of the present invention, a protection resistor is further connected between the control electrode of the control switch and the control signal output port of the control chip.

[0016] According to one embodiment of the present invention, it also includes a driving circuit, which is arranged at the front end of the control electrode of the switching tube. The driving signal is connected to the switching tube through the driving circuit. The driving circuit is used to adjust the driving signal current when the switching tube is turned on or off.

[0017] Compared with the prior art, the advantages and beneficial effects of the switch tube drive control method and switch tube drive control structure of the patent application of the present invention are: The present application can judge the load state connected to the switch tube, and then control and adjust the output voltage of the driving auxiliary power supply according to the load state, so as to realize the rapid adjustment of the gate voltage of the switch tube. It can be seen that it can be optimized according to whether it is heavy load or light load, and can improve the turn-off efficiency of the switch tube under light load state, reduce the switching loss under light load state, and maintain the large current conduction capability of the switch tube under heavy load state, without accelerating the turn-off speed under heavy load state, and control the voltage stress of the switch tube under heavy load state. In this way, the present application can reduce the switching loss while improving the working reliability and stability of the switch tube. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Hereinafter, some specific embodiments of the present invention will be described in detail in an exemplary and non-limiting manner with reference to the accompanying drawings. The same reference numerals in the accompanying drawings indicate the same or similar components or parts. It should be understood by those skilled in the art that these drawings are not necessarily drawn to scale. In the accompanying drawings: Figure 1 It is a structural schematic diagram of a switch tube drive control circuit in the prior art; Figure 2 It is a schematic diagram of the structure of the switch tube drive control circuit in the prior art, wherein the drive circuit adopts an optimized structure of a diode combined with a resistor; Figure 3 It is a schematic diagram of the structure of the switch tube drive control circuit in the prior art, wherein the drive circuit adopts an optimized structure of a triode combined with a resistor; Figure 4 is a schematic diagram of the working process of a switch tube driving control method according to an embodiment of the present invention; Figure 5 is a schematic diagram of a switch tube drive control structure according to an embodiment of the present invention; Figure 6 1 is a schematic diagram of a circuit structure of a switch tube drive control structure according to an embodiment of the present invention, wherein the regulating circuit is a two-speed type; Figure 7 1 is a schematic diagram of a circuit structure of a switch tube drive control structure according to an embodiment of the present invention, wherein the regulating circuit is a continuous type. DETAILED DESCRIPTION

[0019] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0020] In addition, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0021] Switch tube drive control circuit Figure 1As shown, it can generally include a control chip, a driver chip, a driver auxiliary power supply, and a driver circuit, wherein the control chip calculates and gives a control signal to the driver chip based on the sampling of the subsequent working circuit or load circuit connected to the switch tube and the preset control algorithm. The control signal is generally a weak current signal, and the high level is 3.3V or 5V; the driver chip converts the control signal into a drive signal sufficient to turn on the switch tube. The drive signal is generally tens of milliamperes to hundreds of milliamperes, and the high level is 10V to 16V. The specific level value depends on the model of the switch tube to be driven; the driver auxiliary power supply provides a DC power supply for the driver chip; and the drive circuit is used to adjust the drive signal current when the switch tube is turned on and off.

[0022] The switch tube can constitute a functional circuit such as a converter, and the load connected to the switch tube refers to the load connected to the functional circuit. The load state can be divided into a light load state and a heavy load state according to the load power. For example, the full load power of the converter is Pmax. In the prior art, the light load state generally refers to a load rate below 30%, that is, the load power in the light load state is not greater than 0.3Pmax; the heavy load state generally refers to a load rate between 80% and full load, that is, the load power in the heavy load state is not less than 0.8Pmax.

[0023] In order to improve the turn-off loss of the switch tube under light load conditions, the existing technology adopts Figure 2 The circuit structure shown optimizes the structure of the driving circuit. Specifically, in the driving circuit, a diode D21 is connected in series with a resistor R22 and then in parallel with the resistor R21, so that the gate resistance of the switch tube when it is turned on is R21, and the gate resistance when it is turned off is reduced to the parallel resistance of R21 and R22, which speeds up the turn-off speed of the switch tube to reduce the turn-off loss of the switch tube when it is lightly loaded. However, after the above hardware parameter design is determined, the turn-off speed of the switch tube in the heavy load state is also accelerated. Under heavy load conditions, the conduction loss is dominant, and the turn-off loss accounts for a small proportion. Accelerating the turn-off speed of the switch tube has little effect on efficiency optimization, and the turn-off voltage spike will increase due to the accelerated turn-off of the large current of the switch tube, reducing the reliability of the switch tube.

[0024] In another prior art, Figure 3 As shown, a transistor Q31 is added to the drive circuit, so that the gate resistance of the switch tube when it is turned on is R31 plus R32, and the gate resistance when it is turned off is reduced to R32, which speeds up the turn-off speed of the switch tube and reduces the turn-off loss of the converter when it is lightly loaded. Figure 2In the existing solution shown, the current amplification effect of transistor Q31 reduces the requirement for the driver chip to extract the gate charge of the switch tube. However, after the hardware parameter design is determined, the switch tube shutdown speed of the converter is also accelerated when it is overloaded. Under heavy load conditions, the conduction loss is dominant, and the shutdown loss accounts for a small proportion. Accelerating the switch tube shutdown speed has little effect on efficiency optimization, and the shutdown voltage spike will increase due to the large current of the switch tube, reducing the reliability of the switch tube.

[0025] Embodiment 1: This embodiment describes a switch tube drive control method, which determines whether the load state connected to the switch tube is a light load state or a heavy load state, controls the output voltage of the driving auxiliary power supply according to the load state, and further controls the gate voltage of the switch tube, wherein: When the load state is a heavy load state, the output voltage of the driving auxiliary power supply is controlled to increase, thereby increasing the high level voltage of the gate driving signal of the switch tube, which can generally be 12V~15V; When the load state is a light load state, the output voltage of the driving auxiliary power supply is controlled to decrease, thereby reducing the high level voltage of the driving signal of the gate of the switch tube, which can generally be 8V~12V.

[0026] In this embodiment, a first power threshold is preset, the output signal between the switch tube and the load is sampled and the load power is calculated accordingly, and the load power is compared with the first power threshold. If the load power is greater than the first power threshold, determining that the load state is a heavy load state; If the load power is not greater than the first power threshold, the load state is determined to be a light load state.

[0027] In this embodiment, a converter composed of a switching tube is taken as an example, and the full load power of the converter is denoted as Pmax. The first power threshold is set to 0.6Pmax. The light load state in this embodiment refers to a load rate below 60%, that is, the load power in the light load state is not greater than 0.6Pmax; the heavy load state refers to a load rate between more than 60% and full load, that is, the load power in the heavy load state is greater than 0.6Pmax.

[0028] In this embodiment, the control process is as follows: Figure 4As shown, after the switch tube drive control process 501 in the converter starts, the control chip performs power closed-loop calculation 502 according to the converter signal sampling. According to the sampling and calculation results, the load power connected to the converter can be obtained. By comparing whether the load power is greater than the first power threshold 503, it is determined whether the load state connected to the converter is in a light load state or a heavy load state. If the converter load is not greater than the first power threshold, it can be determined that the load state is a light load state, and the control chip issues an instruction to reduce the output voltage of the drive auxiliary power supply to speed up the switching speed of the switch tube to reduce the switching loss when light load 504; if the converter load is greater than the first power threshold, it can be determined that the load state is a heavy load state, and the control chip issues an instruction to increase the output voltage of the drive auxiliary power supply to ensure the large current conduction capability of the switch tube when heavy load and reduce the turn-off electrical stress 505. Then it is determined whether the switch tube drive control is ended 506, and then the switch tube drive control process (507) is ended, or the next converter sampling and power closed-loop calculation 502 is entered.

[0029] The switch tube drive control method of this embodiment first determines the load state connected to the switch tube, and then controls and adjusts the output voltage of the driving auxiliary power supply according to the load state to achieve rapid adjustment of the gate voltage of the switch tube. It can be seen that it can be optimized according to heavy load or light load, and can improve the switch tube turn-off efficiency under light load state, reduce the switching loss under light load state, and maintain the large current conduction capability of the switch tube under heavy load state, without accelerating the turn-off speed under heavy load state, and control the voltage stress of the switch tube under heavy load state. In this way, the present application can reduce the switching loss while improving the working reliability and stability of the switch tube.

[0030] Embodiment 2: The switch tube drive control method of this embodiment is adjusted and modified on the basis of Embodiment 1. The difference is that two power thresholds are preset to make a more accurate judgment on whether the load state is light load or heavy load, and the intermediate value can be regarded as a normal working condition, thereby reducing the frequency of switch tube drive control and reducing the system workload.

[0031] This embodiment presets a second power threshold and a third power threshold, wherein the second power threshold is greater than the third power threshold. The output signal between the switch tube and the load is sampled and the load power is calculated accordingly, and the load power is compared with the second power threshold and the third power threshold. If the load power is not less than the second power threshold, determining that the load state is a heavy load state; If the load power is not greater than the third power threshold, the load state is determined to be a light load state.

[0032] This embodiment also takes the converter composed of a switching tube as an example, and the full load power of the converter is denoted as Pmax. The second power threshold is set to 0.8Pmax, and the third power threshold is set to 0.3Pmax. The light load state in this embodiment refers to a load rate below 30%, that is, the load power in the light load state is not greater than 0.3Pmax; the heavy load state refers to a load rate between more than 80% and full load, that is, the load power in the heavy load state is not less than 0.8Pmax.

[0033] After determining and acquiring the load state, the switch tube drive control method of Example 1 can be adopted, that is, when the load state is a heavy load state, the output voltage of the drive auxiliary power supply is controlled to increase, thereby increasing the high level voltage of the drive signal of the gate of the switch tube; when the load state is a light load state, the output voltage of the drive auxiliary power supply is controlled to decrease, thereby decreasing the high level voltage of the drive signal of the gate of the switch tube. No further details are given here.

[0034] Embodiment 3: This embodiment describes a switch tube drive control structure, such as Figure 5 As shown, it includes a control chip, a driving auxiliary power supply and a driving chip, wherein the control chip samples the signal of the load connected to the switch tube, and calculates and determines the load state according to the sampling signal, and then sends a control signal to the driving auxiliary power supply according to the load state, and the driving auxiliary power supply adjusts its own output voltage according to the received control signal, and the output voltage of the driving auxiliary power supply is input to the power supply input end of the driving chip, the control input end of the driving chip is connected to the control chip, and the signal output end of the driving chip is connected to the control electrode of the switch tube, and the output signal of the driving chip is used as the driving signal of the switch tube.

[0035] Specifically, if Figure 6 As shown, the driving auxiliary power supply includes a first voltage-dividing resistor, a second voltage-dividing resistor, and a driving auxiliary power supply chip. The first voltage-dividing resistor and the second voltage-dividing resistor are connected in series to form a voltage-dividing circuit. The first end of the voltage-dividing circuit is connected to the output end of the driving auxiliary power supply, and the second end of the voltage-dividing circuit is grounded. The connection point between the first voltage-dividing resistor and the second voltage-dividing resistor is a voltage-dividing feedback point of the voltage-dividing circuit. The feedback control end of the driving auxiliary power supply chip is connected to the voltage-dividing feedback point. The driving auxiliary power supply chip performs closed-loop control on the voltage-dividing feedback point so that the voltage of the voltage-dividing feedback point is maintained at a fixed value Vref. The voltage-dividing feedback point is also connected to a regulating circuit. The regulating circuit connects the regulating resistor in the regulating circuit in parallel with the second voltage-dividing resistor according to the control signal sent by the control chip.

[0036] As for the regulating circuit, it can be designed as a two-stage or even multi-stage regulating circuit structure according to needs, or it can also be designed as a continuous regulating circuit structure. Among them, the two-stage or even multi-stage regulating circuit structure is to control the overall impedance of the effectively intervened regulating resistor by outputting IO signals through the control chip, thereby realizing the regulating resistors of different stages; the continuous regulating circuit structure is to control the overall impedance of the effectively intervened regulating resistor by outputting PWM signals with different duty cycles through the control chip, thereby realizing the regulating resistors of different stages continuously. The above can be set according to user needs; Figure 6 The circuit structure adjustment circuit shown is a two-stage adjustable impedance. Specifically, the adjustment circuit includes a first adjustment resistor and a control switch, the first end of the first adjustment resistor is connected to the voltage-dividing feedback point, the second end of the first adjustment resistor is connected to the first signal pole of the control switch, the second signal pole of the control switch is grounded, the control pole of the control switch is connected to the IO output port of the control chip, the control switch is turned on when the IO output port of the control chip outputs a high level, the first adjustment resistor is connected in parallel with the second voltage-dividing resistor, and a protection resistor R64 is also connected between the control pole of the control switch and the IO output port of the control chip.

[0037] The first voltage-dividing resistor is R61, the second voltage-dividing resistor is R62, and the first adjusting resistor is R63. When the IO output port of the control chip outputs a low level, the output voltage of the output end of the driving auxiliary power supply is Vref*(1+R61 / R62), which relatively reduces the high level voltage of the final driving signal; when the IO output port of the control chip outputs a high level, the output voltage of the output end of the driving auxiliary power supply is Vref*(1+R61 / (R62 / / R63)), which increases the high level voltage of the final driving signal.

[0038] In another embodiment, Figure 7The structure of the regulating circuit of the continuous adjustable impedance is shown. Specifically, the regulating circuit includes a second regulating resistor, a third regulating resistor, a control switch, and a bypass capacitor, wherein the first end of the second regulating resistor is connected to the voltage-dividing feedback point, the second end of the second regulating resistor is connected to the first end of the bypass capacitor and the first end of the third regulating resistor, the second end of the bypass capacitor is grounded, the second end of the third regulating resistor is connected to the first signal pole of the control switch, the second signal pole of the control switch is grounded, the control pole of the control switch is connected to the PWM output port of the control chip, when the PWM output port of the control chip outputs a PWM signal, the control switch is turned on at the peak value corresponding to the PWM signal, when the control switch is turned on, the second regulating resistor is connected in series with the third regulating resistor and then connected in parallel with the second voltage-dividing resistor, and a protective resistor R75 is also connected between the control pole of the control switch and the PWM output port of the control chip.

[0039] The first voltage-dividing resistor is R71, the second voltage-dividing resistor is R72, the second regulating resistor is R73, the third regulating resistor is R74, the duty cycle of the PWM signal is D, and the output voltage of the output end of the driving auxiliary power supply is Vref[(1+R71 / R72)*(1-D)+(1+R71 / (R72 / / (R73+R74)))*D].

[0040] When the control chip determines that the load state of the converter is in a light load state, the duty cycle of the PWM signal output by the control chip is low, which reduces the high-level voltage of the switch tube drive signal; when the control chip determines that the load state of the converter is in a heavy load state, the duty cycle of the PWM signal output by the control chip is high, which increases the high-level voltage of the switch tube drive signal. It can be seen that the high-level voltage of the switch tube drive signal can be continuously adjusted by the duty cycle of the PWM signal output by the control chip. Moreover, the duty cycle of the PWM signal can be associated with the load power of the converter by formula or table lookup, so that the high-level voltage of the switch tube drive signal can be continuously and adaptively adjusted with the load power of the converter.

[0041] Embodiment 4: The switch tube drive control method of this embodiment is adjusted and modified on the basis of the embodiment 1. The difference is that the switch tube drive control structure also includes a drive circuit. The overall structure is similar to Figure 1 The structure is the same as the existing structure shown, but the difference lies in the circuit structure of the driving auxiliary power supply. The driving circuit is arranged at the front end of the control electrode of the switch tube, and the driving signal is connected to the switch tube through the driving circuit. The driving circuit is used to adjust the driving signal current when the switch tube is turned on or off.

[0042] The above embodiments are only for illustrating the technical concept and features of the present invention, and their purpose is to enable people familiar with this technology to understand the contents of the present invention and implement them accordingly. They cannot be used to limit the protection scope of the present invention. Any equivalent changes or modifications made according to the spirit of the present invention should be included in the protection scope of the present invention.

Claims

1. A switch tube drive control method, characterized in that: Determine whether the load state connected to the switch tube is a light load state or a heavy load state, and control the output voltage of the driving auxiliary power supply according to the load state, thereby controlling the gate voltage of the switch tube, wherein: When the load state is a heavy load state, controlling the output voltage of the driving auxiliary power supply to increase, thereby increasing the high level voltage of the driving signal of the gate of the switching tube; When the load state is a light load state, the output voltage of the driving auxiliary power supply is controlled to decrease, thereby reducing the high level voltage of the driving signal of the gate of the switching tube.

2. The switch tube drive control method according to claim 1, characterized in that: A first power threshold is preset, an output signal between the switch tube and the load is sampled and load power is calculated accordingly, and the load power is compared with the first power threshold. If the load power is greater than the first power threshold, determining that the load state is a heavy load state; If the load power is not greater than the first power threshold, the load state is determined to be a light load state.

3. The switch tube drive control method according to claim 1, characterized in that: A second power threshold and a third power threshold are preset, wherein the second power threshold is greater than the third power threshold, The output signal between the switch tube and the load is sampled and the load power is calculated accordingly, and the load power is compared with the second power threshold and the third power threshold. If the load power is not less than the second power threshold, determining that the load state is a heavy load state; If the load power is not greater than the third power threshold, the load state is determined to be a light load state.

4. A switch tube drive control structure, characterized in that: It includes a control chip, a driving auxiliary power supply and a driving chip, among which: The control chip samples the signal of the load connected to the switch tube, calculates and determines the load state according to the sampled signal, and then sends a control signal to the driving auxiliary power supply according to the load state. The driving auxiliary power supply adjusts its own output voltage according to the received control signal. The output voltage of the driving auxiliary power supply is input to the power supply input end of the driving chip. The control input end of the driving chip is connected to the control chip. The signal output end of the driving chip is connected to the control electrode of the switching tube. The output signal of the driving chip is used as the driving signal of the switching tube.

5. The switch tube drive control structure according to claim 4, characterized in that: The driving auxiliary power supply includes a first voltage-dividing resistor, a second voltage-dividing resistor, and a driving auxiliary power supply chip. The first voltage-dividing resistor and the second voltage-dividing resistor are connected in series to form a voltage-dividing circuit. The first end of the voltage-dividing circuit is connected to the output end of the driving auxiliary power supply, and the second end of the voltage-dividing circuit is grounded. The connection point between the first voltage-dividing resistor and the second voltage-dividing resistor is a voltage-dividing feedback point of the voltage-dividing circuit. The feedback control end of the driving auxiliary power supply chip is connected to the voltage-dividing feedback point. The driving auxiliary power supply chip performs closed-loop control on the voltage-dividing feedback point so that the voltage of the voltage-dividing feedback point is maintained at a fixed value Vref. The voltage-dividing feedback point is also connected to a regulating circuit. The regulating circuit connects the regulating resistor in the regulating circuit in parallel with the second voltage-dividing resistor according to a control signal sent by the control chip.

6. The switch tube drive control structure according to claim 5, characterized in that: The regulating circuit includes a first regulating resistor and a control switch, wherein the first end of the first regulating resistor is connected to the voltage divider feedback point, the second end of the first regulating resistor is connected to the first signal electrode of the control switch, the second signal electrode of the control switch is grounded, the control electrode of the control switch is connected to the IO output port of the control chip, and the control switch is turned on when the IO output port of the control chip outputs a high level, and the first regulating resistor is connected in parallel with the second voltage divider resistor.

7. The switch tube drive control structure according to claim 6, characterized in that: The first voltage-dividing resistor is R61, the second voltage-dividing resistor is R62, and the first adjusting resistor is R63. When the IO output port of the control chip outputs a low level, the output voltage of the output end of the driving auxiliary power supply is Vref*(1+R61 / R62); When the IO output port of the control chip outputs a high level, the output voltage of the output end of the driving auxiliary power supply is Vref*(1+R61 / (R62 / / R63)).

8. The switch tube drive control structure according to claim 5, characterized in that: The regulation circuit includes a second regulation resistor, a third regulation resistor, a control switch, and a bypass capacitor. The first end of the second regulation resistor is connected to the voltage divider feedback point, the second end of the second regulation resistor is connected to the first end of the bypass capacitor and the first end of the third regulation resistor, the second end of the bypass capacitor is grounded, the second end of the third regulation resistor is connected to the first signal electrode of the control switch, the second signal electrode of the control switch is grounded, the control electrode of the control switch is connected to the PWM output port of the control chip, when the PWM output port of the control chip outputs a PWM signal, the control switch is turned on at a time corresponding to the peak value of the PWM signal, and when the control switch is turned on, the second regulation resistor is connected in series with the third regulation resistor and then connected in parallel with the second voltage divider resistor.

9. The switch tube drive control structure according to claim 8, characterized in that: The first voltage-dividing resistor is R71, the second voltage-dividing resistor is R72, the second regulating resistor is R73, the third regulating resistor is R74, and the duty cycle of the PWM signal is D. The output voltage of the output end of the driving auxiliary power supply is Vref[(1+R71 / R72)*(1-D)+(1+R71 / (R72 / / (R73+R74)))*D].

10. The switch tube drive control structure according to any one of claims 6 to 9, characterized in that: A protection resistor is also connected between the control electrode of the control switch and the control signal output port of the control chip.

11. The switch tube drive control structure according to claim 4, characterized in that: It also includes a driving circuit, which is arranged at the front end of the control electrode of the switch tube. The driving signal is connected to the switch tube through the driving circuit. The driving circuit is used to adjust the driving signal current when the switch tube is turned on or off.

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