阅读说明：本技术 一种半导体器件短路保护电路及方法 (Semiconductor device short-circuit protection circuit and method ) 是由 熊凯 傅俊寅 黄辉 于 2021-10-29 设计创作，主要内容包括：本发明公开了一种半导体器件短路保护电路,包括驱动控制单元、副边处理单元、原边处理单元及短路检测单元,所述短路检测单元用于检测半导体器件是否短路,并在短路时发出短路信号；所述副边处理单元用于根据短路信号发出降压信号,使得驱动控制单元为半导体器件提供第一驱动电阻,以降低半导体器件的门极电压,且保持其工作状态不变,以及用于将短路信号传输至原边处理单元；所述原边处理单元根据短路信号发出关断信号至副边处理单元,以使得驱动控制单元为半导体器件提供第二驱动电阻,以关断半导体器件。本发明还公开了一种半导体器件短路保护方法。如此,提高了保护电路的可靠性和通用型。(The invention discloses a semiconductor device short-circuit protection circuit, which comprises a drive control unit, a secondary side processing unit, a primary side processing unit and a short-circuit detection unit, wherein the short-circuit detection unit is used for detecting whether a semiconductor device is short-circuited or not and sending a short-circuit signal when the semiconductor device is short-circuited; the secondary side processing unit is used for sending a voltage reduction signal according to the short circuit signal, enabling the driving control unit to provide a first driving resistor for the semiconductor device so as to reduce the gate voltage of the semiconductor device and keep the working state of the semiconductor device unchanged, and transmitting the short circuit signal to the primary side processing unit; and the primary side processing unit sends a turn-off signal to the secondary side processing unit according to the short-circuit signal so that the driving control unit provides a second driving resistor for the semiconductor device to turn off the semiconductor device. The invention also discloses a short-circuit protection method of the semiconductor device. Thus, the reliability and general-purpose type of the protection circuit are improved.)

1. A semiconductor device short-circuit protection circuit is characterized by comprising a drive control unit, a secondary side processing unit, a primary side processing unit and a short-circuit detection unit, wherein the output end of the drive control unit is electrically connected with a gate pole of a semiconductor device, the input end of the drive control unit is electrically connected with the secondary side processing unit, the primary side processing unit is electrically connected with the secondary side processing unit, the input end of the short-circuit detection unit is electrically connected with a collector electrode of the semiconductor device, and the output end of the short-circuit detection unit is electrically connected with the secondary side processing unit;

the short circuit detection unit is used for detecting whether the semiconductor device is short-circuited in real time and sending a short circuit signal to the secondary side processing unit when the semiconductor device is short-circuited;

the secondary side processing unit is used for sending a voltage reduction signal to the drive control unit according to the short circuit signal, so that the drive control unit provides a first drive resistor for the semiconductor device to reduce the gate voltage of the semiconductor device and keep the working state of the semiconductor device unchanged, and is used for transmitting the short circuit signal to the primary side processing unit;

and the primary side processing unit sends a turn-off signal according to the short circuit signal and transmits the turn-off signal to the drive control unit through the secondary side processing unit, so that the drive control unit provides a second drive resistor for the semiconductor device to turn off the semiconductor device with the gate voltage reduced.

2. The semiconductor device short-circuit protection circuit of claim 1, wherein an isolation unit is included between the primary processing unit and the secondary processing unit.

3. The semiconductor device short-circuit protection circuit according to claim 1, wherein the driving control unit comprises a MOS transistor (Q1), a MOS transistor (Q2), a MOS transistor (Q3), a resistor (R1), a resistor (R2) and a resistor (R3), the gate of the MOS transistor (Q1) is electrically connected to the secondary processing unit, the source of the MOS transistor (Q1) is electrically connected to the power supply (V1), the drain of the MOS transistor (Q1) is electrically connected to the gate of the semiconductor device through the resistor (R1), the gate of the MOS transistor (Q2) is electrically connected to the secondary processing unit, the source of the MOS transistor (Q2) is electrically connected to the power supply (V2), the drain of the MOS transistor (Q2) is electrically connected to the gate of the semiconductor device through the resistor (R2), the gate of the MOS transistor (Q3) is electrically connected to the secondary processing unit, and the source of the MOS transistor (Q3) is electrically connected to the V3), the drain electrode of the MOS tube (Q3) is electrically connected with the gate electrode of the semiconductor device through the resistor (R3).

4. The semiconductor device short-circuit protection circuit according to claim 1, wherein the semiconductor device is an IGBT or SiC.

5. A short-circuit protection method for a semiconductor device is characterized by comprising the following steps:

s1, detecting whether the semiconductor device is short-circuited in real time, and sending a short-circuit signal to the secondary side processing unit when the semiconductor device is short-circuited;

s2, sending a voltage reduction signal after the logic processing is carried out on the short-circuit signal through the secondary side processing unit, and controlling to provide a first driving resistor for the semiconductor device so as to reduce the gate voltage of the semiconductor device and keep the working state of the semiconductor device unchanged;

s3, transmitting the short-circuit signal to the primary side processing unit through the secondary side processing unit, and sending a turn-off signal to the secondary side processing unit after the primary side processing unit logically processes the short-circuit signal;

and S4, controlling to provide a second driving resistor for the semiconductor device according to the turn-off signal transmitted by the secondary side processing unit so as to turn off the semiconductor device.

6. The semiconductor device short-circuit protection method according to claim 5, wherein the semiconductor device is an IGBT or SiC.

Technical Field

The invention relates to the technical field of IGBT driving, in particular to a semiconductor device short-circuit protection circuit and a semiconductor device short-circuit protection method.

Background

Since the short circuit withstand time of a semiconductor device is limited, the short circuit protection response time needs to be fully considered when designing a short circuit protection circuit, and the semiconductor device must be turned off within a predetermined time to prevent the device from being damaged.

The short circuit withstand time of different semiconductor devices is different, for example, the short circuit withstand time of a Si device can reach 10us generally, while a SiC device can only withstand 3-4 us generally, the conventional short circuit protection technology sets the short circuit response time by detecting the voltage drop of the VCE of the semiconductor device generally, sends a fault signal after the response time is over, and turns off the device through logic control to realize the short circuit protection function, but the following problems usually exist in the existing scheme:

1. the existing short-circuit protection circuit can only be designed according to the short-circuit bearing time given by the specification parameters of the semiconductor device, and because the short-circuit bearing time of the device is short, and in addition, the original secondary side logic processing is required to be carried out to turn off the device when the short-circuit fault occurs, the real short-circuit time often exceeds the rated time, and the risk of damaging the device exists;

2. in the prior art, the charging and discharging time of an RC (resistor-capacitor) in a short-circuit protection circuit and the original secondary side logic processing time can be changed generally, and the device loss within a certain time when short-circuit protection occurs can not be reduced.

Disclosure of Invention

Therefore, it is desirable to provide a general-purpose short-circuit protection circuit and method for a semiconductor device, which can prolong the short-circuit endurance time and improve the anti-interference capability and reliability of the circuit.

The technical scheme provided by the invention for achieving the purpose is as follows:

a semiconductor device short-circuit protection circuit comprises a drive control unit, a secondary side processing unit, a primary side processing unit and a short-circuit detection unit, wherein the output end of the drive control unit is electrically connected with a gate pole of a semiconductor device, the input end of the drive control unit is electrically connected with the secondary side processing unit, the primary side processing unit is electrically connected with the secondary side processing unit, the input end of the short-circuit detection unit is electrically connected with a collector electrode of the semiconductor device, and the output end of the short-circuit detection unit is electrically connected with the secondary side processing unit;

the short circuit detection unit is used for detecting whether the semiconductor device is short-circuited in real time and sending a short circuit signal to the secondary side processing unit when the semiconductor device is short-circuited;

the secondary side processing unit is used for sending a voltage reduction signal to the drive control unit according to the short circuit signal, so that the drive control unit provides a first drive resistor for the semiconductor device to reduce the gate voltage of the semiconductor device and keep the working state of the semiconductor device unchanged, and is used for transmitting the short circuit signal to the primary side processing unit;

and the primary side processing unit sends a turn-off signal according to the short circuit signal and transmits the turn-off signal to the drive control unit through the secondary side processing unit, so that the drive control unit provides a second drive resistor for the semiconductor device to turn off the semiconductor device with the gate voltage reduced.

Furthermore, an isolation unit is at least included between the primary side processing unit and the secondary side processing unit.

Further, the drive control unit comprises a MOS transistor (Q1), a MOS transistor (Q2), a MOS transistor (Q3), a resistor (R1), a resistor (R2) and a resistor (R3), the grid electrode of the MOS tube (Q1) is electrically connected with the secondary side processing unit, the source electrode of the MOS tube (Q1) is electrically connected with a power supply (V1), the drain electrode of the MOS transistor (Q1) is electrically connected with the gate electrode of the semiconductor device through the resistor (R1), the grid electrode of the MOS tube (Q2) is electrically connected with the secondary side processing unit, the source electrode of the MOS tube (Q2) is electrically connected with a power supply (V2), the drain electrode of the MOS transistor (Q2) is electrically connected with the gate electrode of the semiconductor device through the resistor (R2), the grid electrode of the MOS tube (Q3) is electrically connected with the secondary side processing unit, the source electrode of the MOS tube (Q3) is electrically connected with a power supply (V3), the drain electrode of the MOS tube (Q3) is electrically connected with the gate electrode of the semiconductor device through the resistor (R3).

Further, the semiconductor device is an IGBT or SiC.

A short-circuit protection method for a semiconductor device comprises the following steps:

s1, detecting whether the semiconductor device is short-circuited in real time, and sending a short-circuit signal to the secondary side processing unit when the semiconductor device is short-circuited;

s2, sending a voltage reduction signal after the logic processing is carried out on the short-circuit signal through the secondary side processing unit, and controlling to provide a first driving resistor for the semiconductor device so as to reduce the gate voltage of the semiconductor device and keep the working state of the semiconductor device unchanged;

s3, transmitting the short-circuit signal to the primary side processing unit through the secondary side processing unit, and sending a turn-off signal to the secondary side processing unit after the primary side processing unit logically processes the short-circuit signal;

and S4, controlling to provide a second driving resistor for the semiconductor device according to the turn-off signal transmitted by the secondary side processing unit so as to turn off the semiconductor device.

Further, the semiconductor device is an IGBT or SiC.

The invention has the beneficial effects that:

1. according to the invention, the gate voltage control circuit is adopted to improve the current situation, the gate voltage and the short-circuit current are in positive correlation when the semiconductor device is in short circuit, and the gate voltage is reduced by adjusting, so that the short-circuit current of the device is reduced, the instantaneous loss when the short circuit occurs is reduced, the short-circuit bearing time is prolonged, and the anti-interference capability of the short-circuit detection circuit is improved.

2. The invention can turn off the semiconductor device within a predetermined time, thereby improving the versatility of the circuit.

3. The high short circuit turn-off peak can be differentiated into two times of low turn-off peaks, so that the damage of devices caused by overhigh turn-off peak voltage is avoided, and the reliability of the circuit is improved.

Drawings

Fig. 1 is a block diagram of a semiconductor device short-circuit protection circuit according to a preferred embodiment of the present invention.

Fig. 2 is a circuit connection diagram of a preferred embodiment of the driving control unit in fig. 1.

Fig. 3 is a short-circuit waveform diagram of an embodiment of a short-circuit protection circuit of a semiconductor device according to the present invention.

Fig. 4 is a flowchart of a method for short-circuit protection of a semiconductor device according to a preferred embodiment of the present invention.

Description of the main elements

Drive control unit 1

Secondary side processing unit 2

Primary side processing unit 3

Short circuit detection unit 4

Semiconductor device 5

Gate 51

Collector electrode 52

Isolation unit 6

MOS transistors Q1, Q2 and Q3

Resistors R1, R2 and R3

Diodes D1, D2, D3

Power supplies V1, V2

The following detailed description will further illustrate the invention in conjunction with the above-described figures.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention will be described in further detail with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

Referring to fig. 1, the present invention provides a semiconductor device short-circuit protection circuit for reliably turning off a semiconductor device (5) when short-circuit occurs. The semiconductor device short-circuit protection circuit comprises a drive control unit (1), a secondary side processing unit (2), a primary side processing unit (3) and a short-circuit detection unit (4). The output end of the drive control unit (1) is electrically connected with a gate pole (51) of the semiconductor device (5), the input end of the drive control unit (1) is electrically connected with the secondary side processing unit (2), the primary side processing unit (3) is electrically connected with the secondary side processing unit (2), the input end of the short circuit detection unit (4) is electrically connected with a collector electrode (52) of the semiconductor device (5), and the output end of the short circuit detection unit (4) is electrically connected with the secondary side processing unit (2).

The short circuit detection unit (4) is used for detecting whether the semiconductor device (5) is short-circuited in real time and sending a short circuit signal to the secondary side processing unit (2) when the semiconductor device is short-circuited.

The secondary side processing unit (2) is used for sending a voltage reduction signal to the driving control unit (1) according to the short circuit signal, so that the driving control unit (1) provides a first driving resistance for the semiconductor device (5) to reduce the gate voltage of the semiconductor device (5) and keep the working state of the semiconductor device (5) unchanged; and for transmitting the short-circuit signal to the primary side processing unit (3).

The primary side processing unit (3) sends a turn-off signal according to the short circuit signal and transmits the turn-off signal to the driving control unit (1) through the secondary side processing unit (2), so that the driving control unit (1) provides a second driving resistor for the semiconductor device (5) to turn off the semiconductor device with the gate voltage reduced.

In this embodiment, the semiconductor device (5) is an IGBT, and in other embodiments, the semiconductor device (5) may be SiC. The gate (51) and the collector (52) of the semiconductor device (5) are only distinguished expressions of leads, and the type of the semiconductor device is not limited, for example, when the semiconductor device (5) is SiC, the numbers (51) and (52) are respectively corresponding to a gate and a drain. In this embodiment, the off signal is a PWM signal.

In a preferred embodiment, at least one isolation unit (6) is electrically connected between the secondary processing unit (2) and the primary processing unit (3), and the isolation unit (6) is used for isolating a primary low-voltage side from a secondary high-voltage side.

Therefore, the gate voltage of the semiconductor device is reduced and then the semiconductor device is completely turned off, so that the short circuit bearing time of the semiconductor device is prolonged, the phenomenon of mistaken turn-off caused by false short circuit faults caused by interference signals can be avoided, and the anti-interference capability and reliability of the circuit are improved.

Referring to fig. 2, in the present embodiment, the driving control unit (1) includes a MOS transistor (Q1), a MOS transistor (Q2), a MOS transistor (Q3), a resistor (R1), a resistor (R2), and a resistor (R3).

The grid of MOS pipe (Q1) with secondary side processing unit (2) electricity is connected, the source electricity of MOS pipe (Q1) connects power (V1), the drain electrode of MOS pipe (Q1) passes through resistance (R1) is connected with the gate pole electricity of semiconductor device (5). The grid of MOS pipe (Q2) with secondary side processing unit (2) electricity is connected, the source electricity of MOS pipe (Q2) connects power (V2), the drain electrode of MOS pipe (Q2) passes through resistance (R2) is connected with the gate pole electricity of semiconductor device (5). The grid of MOS pipe (Q3) with secondary side processing unit (2) electricity is connected, the source electricity of MOS pipe (Q3) connects power (V2), the drain electrode of MOS pipe (Q3) passes through resistance (R3) is connected with the gate pole electricity of semiconductor device (5).

In the present embodiment, the drive control unit (1) further includes a diode (D1), a diode (D2), and a diode (D3). The anode and the cathode of the diode (D1) are respectively and electrically connected with the drain and the source of the MOS tube (Q1). The anode and the cathode of the diode (D2) are respectively and electrically connected with the source and the drain of the MOS tube (Q2). The anode and the cathode of the diode (D3) are respectively and electrically connected with the source and the drain of the MOS tube (Q3). The diode (D1), the diode (D2) and the diode (D3) are diodes corresponding to the MOS tube body or diodes connected with the MOS tube body in anti-parallel connection externally, and are mainly used for clamping and freewheeling.

The specific working principle of the circuit provided by the embodiment is as follows:

when the IGBT is not short-circuited, a control signal (PWM signal) sent by the primary side processing unit (3) is transmitted to the drive control unit (1) through the secondary side processing unit (2), the conduction state of the MOS tube (Q1) and the MOS tube (Q2) is controlled through the control signal, the MOS tube (Q1) is conducted to provide a drive turn-on signal for the IGBT, the MOS tube (Q2) is conducted to provide a drive turn-off signal for the IGBT, and the MOS tube (Q3) is conducted to control the turn-off state.

When the IGBT is short-circuited, referring to fig. 3, the IGBT turn-off process will be divided into three phases:

in the first stage, the short-circuit detection unit (4) detects that the IGBT is short-circuited after a period of response time, and sends a short-circuit signal to the secondary side processing unit (2), the IGBT in the stage keeps the current working state unchanged, the MOS transistor (Q1) is turned on, the MOS transistor (Q2) is turned off, and the MOS transistor (Q3) is turned off.

In the second stage, after the secondary side processing unit (2) receives the short-circuit signal, a voltage reduction signal is output, so that the MOS tube (Q3) is switched on, and as the MOS tube (Q1) and the MOS tube (Q3) are switched on simultaneously, the gate voltage of the IGBT is reduced through the resistance voltage division of the resistor (R1) and the resistor (R3), so that the short-circuit current is reduced, and the IGBT still continues to be in the working state; at the same time, the secondary processing unit (2) transmits the short-circuit signal to the primary processing unit (3).

And in the third stage, after the primary side processing unit (3) carries out logic processing according to the short-circuit signal, a PWM signal is sent out and transmitted to the secondary side processing unit (2) to control the cut-off of an MOS (metal oxide semiconductor) transistor (Q1), so that the gate voltage of the IGBT is discharged from the resistor (R3) and is cut off.

As can be seen from the short-circuit waveform diagram in fig. 3, the turn-off process of the IGBT is divided into two times, and a higher short-circuit turn-off spike can be divided into two lower turn-off spikes, so that overvoltage damage of the device due to an excessively high turn-off spike is avoided.

Referring to fig. 4, the present invention further provides a method for protecting a short circuit of a semiconductor device, including the following steps:

s1, detecting whether the semiconductor device is short-circuited in real time, and sending a short-circuit signal to the secondary side processing unit when the semiconductor device is short-circuited;

s2, sending a voltage reduction signal after the logic processing is carried out on the short-circuit signal through the secondary side processing unit, and controlling to provide a first driving resistor for the semiconductor device so as to reduce the gate voltage of the semiconductor device and keep the working state of the semiconductor device unchanged;

s3, transmitting the short-circuit signal to the primary side processing unit through the secondary side processing unit, and sending a turn-off signal to the secondary side processing unit after the primary side processing unit logically processes the short-circuit signal;

and S4, controlling to provide a second driving resistor for the semiconductor device according to the turn-off signal transmitted by the secondary side processing unit so as to turn off the semiconductor device.

According to the semiconductor device short-circuit protection circuit and method, the secondary side processing unit (2), the primary side processing unit (3) and the driving control unit (1) are arranged, so that when a semiconductor device (5) is in a short circuit, a short-circuit signal is subjected to logic processing through the secondary side processing unit (2) to output a voltage reduction signal to the driving control unit (1), the driving control unit (1) provides a first driving resistor for the semiconductor device (5), the gate voltage of the semiconductor device (5) is reduced, and the working state of the semiconductor device (5) is kept unchanged; and then the primary side processing unit (3) is used for carrying out logic processing on the short-circuit signal and outputting a corresponding turn-off signal, so that the driving control unit (1) provides a second driving resistor for the semiconductor device (5) and the semiconductor device (5) is completely turned off. Therefore, the short circuit endurance time of the semiconductor device can be prolonged, error turn-off caused by interference can be avoided, and the reliability of the protection circuit is improved.

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents and improvements made within the spirit and principle of the present invention are intended to be included within the scope of the present invention.