CN209419479U - The straight-through protection circuit of output and high voltage integrated circuit - Google Patents

Abstract

The utility model discloses a kind of straight-through protection circuit of output; applied in high voltage integrated circuit, which includes that upper and lower bridge arm switch, the first driving circuit for switching with upper and lower bridge arm one-to-one connection and the second driving circuit and the first driving circuit of control and the second driving circuit respectively export the pwm chip that driving signal is switched to corresponding upper and lower bridge arm all the way；The straight-through protection circuit of output includes the first shaping circuit, power module, switching circuit, voltage regulator circuit, the second shaping circuit and logic processing circuit.The utility model solves reduction voltage circuit of the straight-through protection circuit of current output due to that need to use the special decompression compositions such as chip or transformer, leads to the problem of increasing high voltage integrated circuit chip area and cost.

Description

Output through protection circuit and high-voltage integrated circuit

Technical Field

The utility model relates to a high-voltage integrated circuit technical field, in particular to direct protection circuit of output and high-voltage integrated circuit.

Background

The high-voltage integrated circuit integrates a high-voltage power device and a low-voltage circuit into the same chip, and is commonly used in various display driving, lighting and motor driving. The topological structure of the traditional high-voltage integrated circuit comprises a half-bridge system structure, a full-bridge system structure, a three-phase system structure and the like, and if upper and lower bridge arm tubes driven by the high-voltage integrated circuit are directly connected, the bridge arm is short-circuited, large current is generated, and a power tube is exploded.

In order to avoid the above phenomena, the conventional high-voltage integrated circuit chip usually employs an output pass-through protection circuit, and generates a control signal by detecting a signal at an input end to control output states of a high-end driver and a low-end driver, thereby realizing protection of an upper arm tube and a lower arm tube. Because the output direct connection protection needs to convert a high-voltage signal output by a high end into a control signal which can be used for a low-voltage circuit, a special voltage reduction circuit formed by a voltage reduction chip or a transformer needs to be used, the chip area and the cost are increased, and the output direct connection protection is less used in practical application.

SUMMERY OF THE UTILITY MODEL

The utility model aims at providing an output through protection circuit and high voltage integrated circuit aims at solving present output through protection circuit owing to need use the step-down circuit that constitutes such as special step-down chip or transformer, leads to having increased the problem of high voltage integrated circuit chip area and cost.

In order to achieve the above object, the present invention provides an output pass-through protection circuit, which is applied to a high-voltage integrated circuit, wherein the high-voltage integrated circuit comprises an upper bridge arm switch, a lower bridge arm switch, a first driving circuit and a second driving circuit which are connected with the upper bridge arm switch and the lower bridge arm switch in a one-to-one manner, and a PWM control chip which controls the first driving circuit and the second driving circuit to output a driving signal to the corresponding upper bridge arm switch and the corresponding lower bridge arm switch respectively; the output direct-connection protection circuit comprises a first shaping circuit, a power supply module, a switching circuit, a voltage stabilizing circuit, a second shaping circuit and a logic processing circuit, wherein the input end of the first shaping circuit is used for being connected with the output end of the first driving circuit, and the output end of the first shaping circuit is connected with the controlled end of the switching circuit; the first connecting end of the switch circuit is connected with the power supply module, and the second connecting end of the switch circuit is connected with the input end of the voltage stabilizing circuit; the output end of the voltage stabilizing circuit is connected with the input end of the second shaping circuit; the output end of the second shaping circuit is connected with the first input end of the logic processing circuit; the second input end of the logic processing circuit is used for being connected with the output end of the second driving circuit; the output end of the logic processing circuit is used for being connected with the enabling end of the PWM control chip; wherein,

the first shaping circuit is used for shaping and outputting the high/low level signal waveform output by the first driving circuit;

the switch circuit is used for being switched on when receiving a low-level signal output by the first shaping circuit and being switched off when receiving a high-level signal output by the first shaping circuit;

the voltage stabilizing circuit is used for stabilizing the power supply voltage output by the power supply module and then outputting the power supply voltage when the switching circuit is switched on;

the second shaping circuit is used for carrying out waveform shaping on the level signal output by the voltage stabilizing circuit after voltage stabilization;

and the logic processing circuit is used for outputting an enable signal to the PWM control chip when the level state output by the second shaping circuit and the level state set output by the second driving circuit meet a preset level state set so as to turn off the outputs of the first driving circuit and the second driving circuit.

Optionally, the first shaping circuit is a first inverter, an input end of the first inverter is an input end of the first shaping circuit, and an output end of the first inverter is an output end of the first shaping circuit.

Optionally, the switch circuit is a first electronic switch, the controlled end of the first electronic switch is the controlled end of the switch circuit, the first connection end of the first electronic switch is the first connection end of the switch circuit, and the second connection end of the first electronic switch is the second connection end of the switch circuit.

Optionally, the voltage stabilizing circuit includes a first current limiting element, a first voltage stabilizing element and a voltage dividing circuit, a first end of the first current limiting element is an input end of the voltage stabilizing circuit, and a second end of the first current limiting element, a first end of the first voltage stabilizing element and a first end of the voltage dividing circuit are interconnected; the second end of the first voltage stabilizing element is grounded; the second end of the voltage division circuit is grounded, and the output end of the voltage division circuit is the output end of the voltage stabilizing circuit.

Optionally, the first current limiting element is a first resistor, a first end of the first resistor is a first end of the first current limiting element, and a second end of the first resistor is a second end of the first current limiting element.

Optionally, the first voltage stabilizing element is a first voltage stabilizing diode, a first end of the first voltage stabilizing diode is a first end of the first voltage stabilizing element, and a second end of the first voltage stabilizing diode is a second end of the first voltage stabilizing element.

Optionally, the voltage dividing circuit includes a second resistor and a third resistor, a first end of the second resistor is a first end of the voltage dividing circuit, and a second end of the second resistor is connected to a first end of the third resistor; the second end of the third resistor is the second end of the voltage division circuit; and the common end of the second resistor and the third resistor is the output end of the voltage division circuit.

Optionally, the second shaping circuit includes a second inverter and a third inverter, an input end of the second inverter is an input end of the second shaping circuit, and an output end of the second inverter is connected to an input end of the third inverter; the output end of the third inverter is the output end of the second shaping circuit.

Optionally, the logic processing circuit is a nand gate, a first input of the nand gate is a first input of the logic processing circuit, a second input of the nand gate is a second input of the logic processing circuit, and an output of the nand gate is an output of the logic processing circuit.

The utility model also provides a high-voltage integrated circuit, this high-voltage integrated circuit include upper and lower bridge arm switch, with upper and lower bridge arm switch one-to-one connected first drive circuit and second drive circuit and control first drive circuit and second drive circuit respectively output drive signal all the way to the PWM control chip of corresponding upper and lower bridge arm switch, and the straight-through protection circuit of output; the output direct-connection protection circuit comprises a first shaping circuit, a power supply module, a switching circuit, a voltage stabilizing circuit, a second shaping circuit and a logic processing circuit, wherein the input end of the first shaping circuit is used for being connected with the output end of the first driving circuit, and the output end of the first shaping circuit is connected with the controlled end of the switching circuit; the first connecting end of the switch circuit is connected with the power supply module, and the second connecting end of the switch circuit is connected with the input end of the voltage stabilizing circuit; the output end of the voltage stabilizing circuit is connected with the input end of the second shaping circuit; the output end of the second shaping circuit is connected with the first input end of the logic processing circuit; the second input end of the logic processing circuit is used for being connected with the output end of the second driving circuit; the output end of the logic processing circuit is used for being connected with the enabling end of the PWM control chip; the first shaping circuit is used for shaping and outputting a high/low level signal waveform output by the first driving circuit; the switch circuit is used for being switched on when receiving a low-level signal output by the first shaping circuit and being switched off when receiving a high-level signal output by the first shaping circuit; the voltage stabilizing circuit is used for stabilizing the power supply voltage output by the power supply module and then outputting the power supply voltage when the switching circuit is switched on; the second shaping circuit is used for carrying out waveform shaping on the level signal output by the voltage stabilizing circuit after voltage stabilization; and the logic processing circuit is used for outputting an enable signal to the PWM control chip when the level state output by the second shaping circuit and the level state set output by the second driving circuit meet a preset level state set so as to turn off the outputs of the first driving circuit and the second driving circuit.

The utility model discloses two inputs of output through protection circuit connect high-end drive output and low side drive output respectively, through this output through protection circuit production control signal, control the output of high-end drive circuit and low side drive circuit (be first drive circuit and second drive circuit) to output enable signal extremely when the level state set of the level state of second shaping circuit output and second drive circuit output satisfies predetermined level state set first drive circuit with second drive circuit's output, in order to reach through protect function. Specifically, the first shaping circuit, the switching circuit, the voltage stabilizing circuit and the second shaping circuit are arranged at a first input end of the logic processing circuit and used for detecting high-end drive output, a second input end of the logic processing circuit is used for detecting low-end drive output, and when the condition that the switches of the upper bridge arm and the lower bridge arm are directly connected is detected, a low-level voltage signal is output to an enable end EN of the PWM control chip, so that the PWM control chip can switch off the first driving circuit and the second driving circuit. The utility model discloses utilize voltage stabilizing circuit's steady voltage effect, alright convert the high-pressure signal of high-end output into the control signal that can be used to the low-voltage circuit, solved present output through protection circuit owing to need use the step-down circuit that special step-down chip or transformer constitute, increased the problem of chip area and cost.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings needed to be used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the structures shown in the drawings without creative efforts.

Fig. 1 is a schematic diagram of a functional module of the output pass-through protection circuit of the present invention applied to a high-voltage integrated circuit;

fig. 2 is a schematic diagram of a functional module of an embodiment of the output dc protection circuit of the present invention;

fig. 3 is a schematic circuit diagram of an embodiment of the output dc protection circuit of the present invention.

The reference numbers illustrate:

the objects, features and advantages of the present invention will be further described with reference to the accompanying drawings.

Detailed Description

The technical solutions in the embodiments of the present invention will be described clearly and completely with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative efforts belong to the protection scope of the present invention.

It should be noted that, if directional indications (such as upper, lower, left, right, front and rear … …) are involved in the embodiment of the present invention, the directional indications are only used to explain the relative position relationship between the components, the motion situation, etc. in a specific posture (as shown in the drawings), and if the specific posture is changed, the directional indications are changed accordingly.

In addition, if there is a description relating to "first", "second", etc. in the embodiments of the present invention, the description of "first", "second", etc. is for descriptive purposes only and is not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In addition, the technical solutions in the embodiments may be combined with each other, but it must be based on the realization of those skilled in the art, and when the technical solutions are contradictory or cannot be realized, the combination of the technical solutions should not be considered to exist, and is not within the protection scope of the present invention.

The utility model provides a high voltage integrated circuit and be applied to output through protection circuit among the high voltage integrated circuit.

Referring to fig. 1 and 2, in an embodiment of the present invention, the high voltage integrated circuit includes an upper bridge arm switch, a lower bridge arm switch (not shown), a first driving circuit 200 and a second driving circuit 300 connected to the upper bridge arm switch and the lower bridge arm switch in a one-to-one manner, and a PWM control chip 100 for controlling the first driving circuit 200 and the second driving circuit 300 to output a driving signal to the corresponding upper bridge arm switch and the corresponding lower bridge arm switch respectively.

In this embodiment, the PWM signal generated by the PWM control chip 100 is shaped and then outputs two complementary PWM pulse signals: a high-side input signal and a low-side input signal. The high-end input signal drives the upper bridge arm switch to work through the high-end driving circuit, namely the first driving circuit 200, and the low-end input signal drives the lower bridge arm switch to work through the low-end driving circuit, namely the second driving circuit 300, so that the upper bridge arm switch and the lower bridge arm switch are alternately switched on under the normal driving of the PWM control chip. When an abnormality occurs, the upper and lower bridge arm switches may be turned on at the same time, which causes the bridge arm to be short-circuited, i.e. a straight-through phenomenon occurs.

To the straight-through phenomenon that appears in high voltage integrated circuit easily, the utility model provides an output straight-through protection circuit 400.

In an embodiment, the output shoot-through protection circuit 400 includes a first shaping circuit 410, a power module 420, a switching circuit 430, a voltage stabilizing circuit 440, a second shaping circuit 450, and a logic processing circuit 460, wherein an input terminal of the first shaping circuit 410 is configured to be connected to an output terminal of the first driving circuit 200, and an output terminal of the first shaping circuit 410 is connected to a controlled terminal of the switching circuit 430; the first connection end of the switch circuit 430 is connected with the power module 420, and the second connection end of the switch circuit 430 is connected with the input end of the voltage stabilizing circuit 440; the output end of the voltage stabilizing circuit 440 is connected with the input end of the second shaping circuit 450; an output of the second shaping circuit 450 is connected to a first input of the logic processing circuit 460; a second input terminal of the logic processing circuit 460 is configured to be connected to an output terminal of the second driving circuit 300; the output end of the logic processing circuit 460 is used for being connected with the enable end of the PWM control chip 100; wherein,

the first shaping circuit 410 is configured to shape and output the high/low level signal waveform output by the first driving circuit 200;

the switch circuit 430 is configured to be turned on when receiving a low-level signal output by the first shaping circuit 410, and turned off when receiving a high-level signal output by the first shaping circuit 410;

the voltage stabilizing circuit 440 is configured to, when the switch circuit 430 is turned on, output the power voltage output by the power supply module 420 after stabilizing the voltage;

the second shaping circuit 450 is configured to perform waveform shaping on the level signal output after the voltage stabilizing circuit 440 stabilizes;

the logic processing circuit 460 is configured to output an enable signal to the PWM control chip 100 to turn off the outputs of the first driving circuit 200 and the second driving circuit 300 when the level state output by the second shaping circuit 450 and the level state set output by the second driving circuit 300 satisfy a preset level state set.

The first input terminal of the output shoot-through protection circuit 400 is used for inputting the high-side driving signal, i.e. the input terminal of the first shaping circuit 410 is connected to the high-side driving output HO, the high-side driving signal input to the first shaping circuit 410 can be a high/low level voltage signal, the high-side driving signal is shaped by the first shaping circuit 410 and then outputted to the first switch circuit 430, controlling the on/off of the high-side driving signal, for example, when the low level signal inputted to the first switch circuit 430 reaches the turn-on threshold of the switch circuit 430, the first switch circuit 430 is turned on, the switch circuit 430 outputs the voltage signal output by the power module 420 to the voltage stabilizing circuit 440, the voltage is stabilized by the voltage stabilizing circuit 440, the signal is converted into a low voltage signal for the low voltage circuit to work, and then the low voltage signal is output to the second shaping circuit 450, and then the waveform of the signal is shaped by the second shaping circuit 450 and finally input to the first input end of the logic processing circuit 460. It is understood that the signal input to the first input terminal of the logic processing circuit 460 is a high level or low level voltage signal.

The second input of logic processing circuit 460 is connected to the low-side drive output LO, i.e., the second input of logic processing circuit 460 is used for inputting a low-side drive signal, it being understood that the low-side drive signal may be a high-level or low-level voltage signal.

In this embodiment, when the upper and lower bridge arm switches of the high voltage integrated circuit are turned on simultaneously, the first input terminal and the second input terminal corresponding to the logic processing circuit 460 input high level voltage signals. Specifically, a high-level voltage signal is input to the input terminal of the first shaping circuit 410, and is output after shaping, so as to control the switch circuit 430 to be turned on, so that the voltage-stabilizing circuit 440 stabilizes the power voltage output by the power module 420 and outputs the stabilized power voltage to the second shaping circuit 450, and the second shaping circuit 450 outputs a high-level voltage control signal to the first input terminal of the logic processing circuit 460; the second input terminal of the logic processing circuit 460 inputs a voltage signal which is also at a high level. At this time, the voltage signal is converted into a low level voltage signal by the logic processing circuit 460 and is output to the enable terminal of the PWM control chip by the output terminal OUT, so that the PWM control chip turns off the first driving circuit 200 and the second driving circuit 300, thereby protecting the switching tubes in the upper and lower bridge arms. The current output pass-through protection circuit 400 needs a voltage reduction circuit because a high-voltage signal of the high-end output HO needs to be converted into a control signal for a low-voltage circuit, which increases the area and cost of a chip. In this embodiment, the voltage stabilizing function of the voltage stabilizing circuit 440 is utilized to convert the high voltage signal of the high-side driver output HO into a control signal for the low voltage circuit, thereby simplifying the circuit structure and reducing the chip area.

The utility model discloses two inputs of output through protection circuit 400 connect high-end drive output HO and low-end drive output LO respectively, through this output through protection circuit 400 and produce control signal, control the output of high-end drive circuit and low-end drive circuit (being first drive circuit 200 and second drive circuit 300) to output enable signal extremely when the level state of second shaping circuit 450 output and the level state set of second drive circuit 300 output satisfy predetermined level state set first drive circuit 200 with second drive circuit 300's output, in order to reach through protect function. Specifically, the first shaping circuit 410, the switching circuit 430, the voltage stabilizing circuit 440, and the second shaping circuit 450 are disposed at a first input end of the logic processing circuit 460, and are configured to detect the high-side driving output HO, and a second input end of the logic processing circuit 460 is configured to detect the low-side driving output LO, and when it is detected that the power transistors of the same bridge arm of the circuits such as the full bridge or the half bridge are directly connected, the output end OUT outputs a low-level voltage signal to the enable end EN of the PWM control chip, so that the PWM control chip turns off the first driving circuit 200 and the second driving circuit 300. The utility model discloses utilize voltage stabilizing circuit 440's steady voltage effect, alright convert the high-voltage signal of high-end output HO into the control signal that can be used to the low-voltage circuit, solved present output through protection circuit 400 owing to need use the step-down circuit that special step-down chip or transformer constitute, increased the problem of chip area and cost.

Referring to fig. 3, in an alternative embodiment, the first shaping circuit 410 is a first inverter INV1, an input terminal of the first inverter INV1 is an input terminal of the output pass protection circuit 400, and an output terminal of the first inverter INV1 is an output terminal of the first shaping circuit 410.

In this embodiment, the first shaping circuit 410 is implemented by a first inverter INV1, and when the high-side driving output HO outputs a high level, the output goes low through a first inverter INV 1.

Referring to fig. 3, in an alternative embodiment, the switch circuit 430 is a first electronic switch K, a controlled terminal of the first electronic switch K is an input terminal of the switch circuit 430, a first connection terminal of the first electronic switch K is connected to the power module VB, and a second connection terminal of the first electronic switch K is an output terminal of the switch circuit 430.

In this embodiment, the switch circuit 430 is a first electronic switch K, and the first electronic switch K can be implemented by using original components such as MOS and triode. In this embodiment, the first electronic switch K is implemented by a PMOS transistor, a gate of the PMOS transistor is a controlled terminal of the first electronic switch K, a source of the PMOS transistor is a first connection terminal of the first electronic switch K, and a drain of the PMOS transistor is a second connection terminal of the first electronic switch K, that is, when the first driving circuit 200 outputs a high level, a low level is output through the first inverter INV1, and when a voltage control signal of the low level reaches a turn-on threshold of the PMOS, the PMOS is turned on.

Referring to fig. 3, in an alternative embodiment, the stabilizing circuit 440 includes a first current limiting element R1, a first voltage stabilizing element ZD, and a voltage dividing circuit 441, a first terminal of the first current limiting element R1 is an input terminal of the stabilizing circuit 440, and a second terminal of the first current limiting element R1, a first terminal of the first voltage stabilizing element ZD, and a first terminal of the voltage dividing circuit 440 are interconnected; a second end of the first voltage stabilizing element ZD is grounded; the second terminal of the voltage dividing circuit 441 is grounded, and the output terminal of the voltage dividing circuit 441 is the output terminal of the voltage stabilizing circuit 440.

In this embodiment, the first current limiting element R1 may be implemented by using a first resistor R1, and the first voltage stabilizing element ZD may be implemented by using a first voltage stabilizing diode.

Further, the voltage dividing circuit 441 includes a second resistor R2 and a third resistor R3, a first end of the second resistor R2 is a first end of the voltage dividing circuit 440, and a second end of the second resistor R2 is connected to a first end of the third resistor R3; the second end of the third resistor R3 is the second end of the voltage divider circuit 441; the common terminal of the second resistor R2 and the third resistor R3 is the output terminal of the voltage divider circuit 441.

When a PMOS (P-channel metal oxide semiconductor) tube of the switch circuit is conducted, a drain electrode of the PMOS tube outputs a high level, the high level is limited by a first resistor R1 and then is output to a cathode of a first voltage-stabilizing diode ZD, a cathode of the first voltage-stabilizing diode ZD is connected with a first end of a second resistor R2, an anode of the first voltage-stabilizing diode ZD is connected with a second end of a third resistor R3, the first voltage-stabilizing diode ZD equivalently stabilizes the input voltage of the voltage-dividing circuit 441 at a reference voltage, and the voltage is divided by a second resistor R2 and a third resistor R3 and then is output as the voltage at two ends of the third resistor R3. The high voltage output by the drain electrode of the PMOS tube can be reduced and then output.

It can be understood that the voltage stabilizing circuit 440 can implement a voltage reducing function implemented by using a voltage reducing chip, a transformer, etc. in a conventional high voltage integrated circuit by providing the first resistor R1, the first zener diode ZD, the second resistor R2 and the third resistor R3, thereby reducing the area and cost of the chip and realizing mass production.

Referring to fig. 3, in an alternative embodiment, the second shaping circuit 450 includes a second inverter INV2 and a third inverter INV3, an input terminal of the second inverter INV2 is an input terminal of the second shaping circuit 450, and an output terminal of the second inverter INV2 is connected to an input terminal of the third inverter INV 3; an output end of the third inverter INV3 is an output end of the second shaping circuit 450.

In this embodiment, the second shaping circuit 450 is implemented by using two inverters, i.e., a second inverter INV2 and a third inverter INV3, and outputs a high level when the high level output after voltage reduction by the voltage stabilizing circuit 440 is inverted twice by the second inverter INV2 and the third inverter INV 3.

By providing the second inverter INV2 and the third inverter INV3, because the high level output from the previous stage is not the standard level or the waveform is not ideal, two consecutive inverters are used to shape the waveform and change the waveform into the high level output of the standard voltage, so as to achieve the purpose of shaping.

Referring to fig. 3, in an alternative embodiment, the logic processing circuit 460 is a NAND gate NAND, a first input of the NAND gate NAND is a first input of the logic processing circuit 460, a second input of the NAND gate NAND is a second input of the logic processing circuit 460, and an output of the NAND gate NAND is an output of the logic processing circuit 460.

In this embodiment, by setting the NAND gate NAND, when the second shaping circuit 450 outputs a high level and the second input terminal of the NAND gate NAND, that is, the low-side driving circuit, inputs a high level, at this time, the power transistors of the same bridge arm of the full-bridge or half-bridge circuit are directly connected, and the output terminal OUT of the NAND gate NAND outputs a low level to the enable terminal EN of the PWM control chip 100, so that the PWM control chip 100 turns off the first driving circuit 200 and the second driving circuit 300, thereby protecting the power transistors.

In other cases, the first input terminal of the NAND gate NAND inputs a high level, the second input terminal inputs a low level, or the first input terminal of the NAND gate NAND inputs a low level, the second input terminal inputs a high level, or the first input terminal of the NAND gate NAND inputs a low level, the second input terminal inputs a low level, and in these three cases, the output terminal OUT of the NAND gate NAND outputs a high level, and the first driving circuit 200 and the second driving circuit 300 operate normally.

It can be understood that, because the utility model discloses direct protection circuit 400 of above-mentioned output has been used among the high voltage integrated circuit, consequently, the utility model discloses high voltage integrated circuit's embodiment includes all technical scheme of the whole embodiments of the direct protection circuit 400 of above-mentioned output, and the technological effect that reaches is also identical, no longer gives details here.

The above is only the optional embodiment of the present invention, and not therefore the limit of the patent scope of the present invention, all of which are in the concept of the present invention, the equivalent structure transformation of the content of the specification and the drawings is utilized, or the direct/indirect application is included in other related technical fields in the patent protection scope of the present invention.

Claims (10)

1. An output direct-connection protection circuit is applied to a high-voltage integrated circuit, and the high-voltage integrated circuit comprises an upper bridge arm switch, a lower bridge arm switch, a first driving circuit, a second driving circuit and a PWM control chip, wherein the first driving circuit and the second driving circuit are connected with the upper bridge arm switch and the lower bridge arm switch in a one-to-one mode, and the PWM control chip controls the first driving circuit and the second driving circuit to output one driving signal to the corresponding upper bridge arm switch and the corresponding lower bridge arm switch respectively; the output direct-connection protection circuit is characterized by comprising a first shaping circuit, a power supply module, a switching circuit, a voltage stabilizing circuit, a second shaping circuit and a logic processing circuit, wherein the input end of the first shaping circuit is used for being connected with the output end of the first driving circuit, and the output end of the first shaping circuit is connected with the controlled end of the switching circuit; the first connecting end of the switch circuit is connected with the power supply module, and the second connecting end of the switch circuit is connected with the input end of the voltage stabilizing circuit; the output end of the voltage stabilizing circuit is connected with the input end of the second shaping circuit; the output end of the second shaping circuit is connected with the first input end of the logic processing circuit; the second input end of the logic processing circuit is used for being connected with the output end of the second driving circuit; the output end of the logic processing circuit is used for being connected with the enabling end of the PWM control chip; wherein,

the first shaping circuit is used for shaping and outputting the high/low level signal waveform output by the first driving circuit;

the switch circuit is used for being switched on when receiving a low-level signal output by the first shaping circuit and being switched off when receiving a high-level signal output by the first shaping circuit;

the voltage stabilizing circuit is used for stabilizing the power supply voltage output by the power supply module and then outputting the power supply voltage when the switching circuit is switched on;

the second shaping circuit is used for carrying out waveform shaping on the level signal output by the voltage stabilizing circuit after voltage stabilization;

and the logic processing circuit is used for outputting an enable signal to the PWM control chip when the level state output by the second shaping circuit and the level state set output by the second driving circuit meet a preset level state set so as to turn off the outputs of the first driving circuit and the second driving circuit.

2. The output pass-through protection circuit of claim 1 wherein the first shaping circuit is a first inverter, the input of the first inverter is the input of the first shaping circuit, and the output of the first inverter is the output of the first shaping circuit.

3. The output pass-through protection circuit of claim 1, wherein the switching circuit is a first electronic switch, the controlled terminal of the first electronic switch is the controlled terminal of the switching circuit, the first connection terminal of the first electronic switch is the first connection terminal of the switching circuit, and the second connection terminal of the first electronic switch is the second connection terminal of the switching circuit.

4. The output pass-through protection circuit of claim 1, wherein the regulation circuit includes a first current limiting element, a first voltage stabilizing element, and a voltage divider circuit, a first terminal of the first current limiting element being an input terminal of the regulation circuit, a second terminal of the first current limiting element, a first terminal of the first voltage stabilizing element, and a first terminal of the voltage divider circuit being interconnected; the second end of the first voltage stabilizing element is grounded; the second end of the voltage division circuit is grounded, and the output end of the voltage division circuit is the output end of the voltage stabilizing circuit.

5. The output pass-through protection circuit of claim 4, wherein the first current limiting element is a first resistor, a first end of the first resistor is a first end of the first current limiting element, and a second end of the first resistor is a second end of the first current limiting element.

6. The output pass-through protection circuit of claim 4, wherein the first voltage regulation element is a first voltage regulation diode, the first terminal of the first voltage regulation diode is the first terminal of the first voltage regulation element, and the second terminal of the first voltage regulation diode is the second terminal of the first voltage regulation element.

7. The output pass-through protection circuit of claim 4, wherein the voltage divider circuit comprises a second resistor and a third resistor, a first end of the second resistor is a first end of the voltage divider circuit, and a second end of the second resistor is connected to a first end of the third resistor; the second end of the third resistor is the second end of the voltage division circuit; and the common end of the second resistor and the third resistor is the output end of the voltage division circuit.

8. The output pass-through protection circuit of claim 1, wherein the second shaping circuit comprises a second inverter and a third inverter, an input of the second inverter being an input of the second shaping circuit, an output of the second inverter being connected to an input of the third inverter; the output end of the third inverter is the output end of the second shaping circuit.

9. The output pass-through protection circuit of claim 1, wherein the logic processing circuit is a nand gate, the first input of the nand gate is the first input of the logic processing circuit, the second input of the nand gate is the second input of the logic processing circuit, and the output of the nand gate is the output of the logic processing circuit.

10. A high-voltage integrated circuit is characterized by comprising an upper bridge arm switch, a lower bridge arm switch, a first driving circuit, a second driving circuit, a PWM control chip and an output direct-current protection circuit, wherein the first driving circuit and the second driving circuit are connected with the upper bridge arm switch and the lower bridge arm switch in a one-to-one mode; the input end of a first shaping circuit of the output direct-connection protection circuit is connected with the output end of the first driving circuit; and a second input end of a logic processing circuit of the output direct-connection protection circuit is connected with an output end of the second driving circuit, and an output end of the logic processing circuit of the output direct-connection protection circuit is connected with an enabling end of the PWM control chip.