CN217388672U - Overcurrent protection circuit for semiconductor switch - Google Patents
Overcurrent protection circuit for semiconductor switch Download PDFInfo
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- CN217388672U CN217388672U CN202122994276.4U CN202122994276U CN217388672U CN 217388672 U CN217388672 U CN 217388672U CN 202122994276 U CN202122994276 U CN 202122994276U CN 217388672 U CN217388672 U CN 217388672U
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Abstract
The utility model relates to an overcurrent protection circuit for semiconductor switch, it includes detection module and protection circuit module. The detection module detects a current flowing through the semiconductor switch in the circuit and converts the current into a first signal, and the protection circuit module receives the first signal from the detection module. The protection circuit module is capable of rapidly controlling the semiconductor switch to be turned off when the first signal received from the detection module is higher than a high threshold value, and capable of controlling the semiconductor switch to be turned on with a delay when the first signal received from the detection module is lower than a low threshold value, which is smaller than the high threshold value. The overcurrent protection circuit can reduce the heating of the semiconductor switch and avoid the semiconductor switch from being frequently switched off and being damaged by switching on large short-circuit current under the condition of continuous short circuit.
Description
Technical Field
The present invention relates to an overcurrent protection circuit for a semiconductor switch, and more particularly to an overcurrent protection circuit for a semiconductor switch used in a vehicle power supply system.
Background
In a normally operating circuit, current flows from the positive pole of the power supply through the circuit inside the load and then through the conducting semiconductor switching element in the control box back to the negative pole of the power supply, thereby forming a loop and charging the load. However, when a short circuit occurs in the load, for example, an excessive current caused by the short circuit flows directly through the semiconductor switching device. If the semiconductor switching device does not have an overcurrent protection function, the semiconductor switching device is burned, causing electrical damage to the control box.
Even in the case where the semiconductor switching element has an overcurrent protection function, if the short circuit continues for a long time, in the case where there is no post-short-circuit delay-on function, a cycle of "short circuit-semiconductor switching element off-current drop to 0-short circuit protection release-semiconductor switching element on-short circuit" may occur. Since the semiconductor switching device frequently turns on and off a short-circuit large current, the semiconductor switching device itself accumulates a large amount of heat due to switching loss, resulting in thermal damage to the circuit.
In addition, the overcurrent protection circuits for semiconductor switches in the prior art are usually provided with only one threshold value, in which case fluctuations in the signal will cause the output voltage of the comparator in the circuit to have a small pulse, which is undesirable because it is regarded as a disturbing signal. But the interference signal is unavoidable in the case of only one threshold.
SUMMERY OF THE UTILITY MODEL
The present invention provides an overcurrent protection circuit for a semiconductor switch, which can switch off and on the semiconductor switch within a controllable time under the condition of short circuit in the circuit, thereby reducing the heat generation of the semiconductor switch, and avoiding the damage of the semiconductor switch due to frequent disconnection and connection of a large short-circuit current under the condition of continuous short circuit.
The above object is achieved by an overcurrent protection circuit for a semiconductor switch, comprising:
a detection module that detects a current flowing through the semiconductor switch in the circuit and converts it into a first signal; and
a protection circuit module that receives a first signal from the detection module,
the protection circuit module can control to open the semiconductor switch within a controllable time when the first signal received from the detection module is higher than a high threshold value;
the protection circuit module is capable of controlling turning on the semiconductor switch with a delay when the first signal received from the detection module is below a lower threshold, wherein the lower threshold is less than the upper threshold.
The overcurrent protection circuit can turn on the semiconductor switch in real time in the case of a short circuit occurring in the circuit, thereby achieving protection of the semiconductor switch against adverse effects of frequent turning-off and turning-on in the case of a continuous short circuit. By setting the double thresholds, i.e. the high threshold and the low threshold, the interference signal in the circuit can be avoided, so that the output voltage is stable.
According to a preferable design scheme, the detection module comprises a detection resistor and an amplification filter circuit, the detection resistor detects current flowing through the semiconductor switch in the circuit, and the amplification filter circuit amplifies voltage at two ends of the detection resistor and sends the voltage as a first signal to the protection circuit module. The amplifying and filtering circuit can provide a large signal for the post-circuit, so that the detection resistor with a very small resistance value is enough, and a plurality of resistors are not required to be arranged in the circuit, thereby saving the structural space and reducing the power consumption.
According to a preferred design, the protection circuit module comprises a delay circuit unit, which causes the received first signal to reach the dual threshold comparator unit within a controllable time, and a dual threshold comparator unit, which provides a high threshold and a low threshold and compares the received first signal with the high threshold and the low threshold, respectively, and controls the semiconductor switch to be switched on and off based on the comparison result.
According to a preferred embodiment, the delay circuit unit comprises a capacitor and a first resistor. The capacitor is connected in parallel with the first resistor. The function of the delay control can be simply realized through different charging and discharging loops.
According to a preferred embodiment, the dual-threshold comparator unit comprises a comparator and a second resistor, one end of the second resistor is connected to the output of the comparator and the other end of the second resistor is connected to the non-inverting input of the comparator. The high threshold or the low threshold is realized by connecting a second resistor between the non-inverting input terminal and the output terminal of the comparator.
According to a preferred embodiment, the dual-threshold comparator unit further comprises at least a third resistor and a fourth resistor, one end of the third resistor is connected to ground and the other end is connected to the non-inverting input of the comparator, one end of the fourth resistor is connected to the non-inverting input of the comparator and the other end is connected to the comparator power supply, and the high threshold and the low threshold can be adjusted by changing the resistance value of the second resistor, the third resistor or the fourth resistor. The adjustment of the high threshold value and the low threshold value can thus be achieved by simply setting the resistance values of the respective resistors.
According to a preferred embodiment, the delay circuit unit further comprises at least a fifth resistor, which is connected between the detection module and the parallel circuit of the capacitor and the first resistor, and the delay time for turning on the semiconductor switch and the turn-off time for turning off the semiconductor switch can be adjusted by changing the resistance values of the fifth resistor and the first resistor.
According to a preferred embodiment, the delay circuit unit further includes a fifth resistor and a first diode, and the fifth resistor is arranged in series with the first diode between the detection module and the parallel capacitor and the first resistor. Therefore, the first diode ensures that the current in the circuit charges the capacitor after passing through the fifth resistor and the first diode, and when the capacitor discharges, the current cannot flow back through the first diode and can only discharge through the first resistor. The function of the delay control can be simply realized through different charging and discharging loops.
According to a preferred embodiment, the protection circuit module further comprises a second diode which is connected between the semiconductor switch and the comparator and is connected in the opposite direction to the output of the comparator. When the output end of the comparator outputs low level, the second diode is conducted, and the semiconductor switch is disconnected. When the output end of the comparator outputs high level, the second diode is cut off, and the semiconductor switch is switched on.
According to a preferred embodiment, the resistance value of the fifth resistor is smaller, in particular much smaller, than the resistance value of the first resistor. Whereby the overcurrent protection circuit can quickly enter a protection state, e.g. 10 -6 Seconds, while the release of the protection state requires a second order, for example 10 0 Second, the time difference between the two is nearly million times. Therefore, the semiconductor switch can be promptly turned off at the time of overcurrent protection. The semiconductor switch is turned on with a greater delay after the semiconductor switch is turned off. Therefore, frequent conduction of short-circuit current is avoided, and damage to the semiconductor switch caused by excessive current is prevented.
Drawings
For a better understanding of the above and other objects, features, advantages and functions of the present invention, reference should be made to the preferred embodiments illustrated in the accompanying drawings. Like reference numerals in the drawings refer to like parts. It will be appreciated by persons skilled in the art that the drawings are intended to illustrate preferred embodiments of the invention without any limiting effect on the scope of the invention, and that the various components in the drawings are not to scale.
Fig. 1 shows a circuit diagram of an overcurrent protection circuit for a semiconductor switch according to the present invention.
Fig. 2a-2c show the working principle of a comparator of a dual threshold comparator cell in an overcurrent protection circuit for a semiconductor switch according to the invention.
Fig. 3a and 3c show a circuit diagram and the working principle, respectively, of a prior art single threshold comparator cell.
Fig. 3b and 3d show a circuit diagram and the working principle, respectively, of a dual threshold comparator unit according to the invention.
Detailed Description
The technical solutions of the present invention are further described below by way of specific embodiments with reference to the drawings, but the present invention is not limited to these embodiments. What has been described herein is merely a preferred embodiment in accordance with the present invention, and those skilled in the art will appreciate that other ways of implementing the present invention on the basis of the preferred embodiment will also fall within the scope of the present invention.
Fig. 1 exemplarily shows a circuit diagram of an overcurrent protection circuit for a semiconductor switch according to the present invention. Fig. 1 shows a power source S, which is, for example, a battery in a vehicle. The power supply supplies power to a load B. When the circuit is operating normally, current flows from the positive pole of the power source S through the load B, the semiconductor switch Q2 and the sense resistor R10 and back to the negative pole of the power source S, thereby forming a loop. The semiconductor switch Q2 is a Metal Oxide Semiconductor Field Effect Transistor (MOSFET) in this embodiment, but other semiconductor switches are possible, such as BJTs, IGBTs, etc. Other components may be provided in the circuit, for example, a diode D5 is provided between the load B and the semiconductor switch Q2 in fig. 1.
For example, when a short circuit occurs in a load internal circuit, an excessive current caused by the short circuit directly flows through the semiconductor switch, and thus each component in the circuit is damaged, and therefore an overcurrent protection circuit for the semiconductor switch is required.
According to the utility model discloses an overcurrent protection circuit for semiconductor switch includes detection module and protection circuit module. The detection module detects current flowing through the semiconductor switch in the circuit and converts the current into a first signal; the protection circuit module receives the first signal from the detection module and controls the semiconductor switch to be turned on and off within a controllable time based on the received first signal.
In the embodiment of fig. 1, the sense module includes a sense resistor R10 and an amplification filter circuit 80, and senses the current flowing through the semiconductor switch Q2 in the sense module and converts it into a first signal, for example, the voltage across the sense resistor R10 may be used as the first signal. The amplification filter circuit 80 receives the voltage across the detection resistor R10 as the first signal, and then amplifies the voltage several times. The amplifier filter circuit 80 is provided so that the detection resistor R10 can be a resistor having a very small resistance value. In the present invention, the detection resistor R10 may be, for example, 0.05 ohm. If only the detection resistor R10 having a very small resistance value is provided without an amplification filter circuit, the resistance value is so small that the first signal is easily disturbed. However, if the detection resistor R10 has a large resistance value, the large resistance value causes a problem that the power consumption of the resistor is large; and the larger the resistance value is, the larger the volume of the resistor is. In the basis the utility model discloses an among the overcurrent protection circuit, just can provide a big signal for the post circuit through amplifying filter circuit, it is just enough to adopt the detection resistance R10 that the resistance value is very little from this, need not to set up a plurality of resistances in the circuit, has saved the headroom and has reduced the consumption from this.
The protection circuit module receives the first signal from the detection module where the amplified voltage is received from the amplification filter circuit 80. The protection circuit module comprises a time delay circuit unit and a dual-threshold comparator unit. The delay circuit unit delays the arrival of the received first signal at the dual threshold comparator unit, and the dual threshold comparator unit supplies the high threshold and the low threshold and compares the received first signal with the high threshold and the low threshold, respectively, and controls the semiconductor switch Q2 to be turned on and off based on the comparison result. In the embodiment of fig. 1, the delay circuit unit includes a capacitor C2 and a first resistor R11, and the capacitor C2 is connected in parallel with the first resistor R11. The dual-threshold comparator unit comprises a comparator U5 and a second resistor R14, one end of the second resistor R14 is connected with the output end of the comparator U5, and the other end of the second resistor R14 is connected with the non-inverting input end of the comparator U5. The delay circuit unit is connected to the inverting input of the comparator U5.
When the detection resistor R10 detects that the current flowing through the semiconductor switch is too large, the voltage at the two ends of the detection resistor R10 is taken as a first signal, amplified by the amplification filter circuit and sent to the protection circuit module. After receiving the first signal, the delay circuit unit in the protection circuit module charges the capacitor C2 with the voltage. Here, the capacitance of the capacitor C2 is, for example, 1 μ F. Since the capacitance of capacitor C2 is very small, only a short time is required to charge C2 to the high threshold in the dual threshold comparator cell. When C2 continues to be charged beyond the high threshold, a high level is input to the dual threshold comparator cell, specifically to comparator U5. After the comparator U5 receives the high level, the output terminal OUT outputs a low level to the semiconductor switch, so that the semiconductor switch Q2 is turned off. The semiconductor switch is here formed as a MOSFET, in which case the low level output by the comparator U5 pulls the gate of the MOSFET low, here for example 0V, so that the semiconductor switch Q2 turns off, the current in the circuit drops to zero, and thereby an overcurrent protection state is entered.
The current in the circuit is zero at this time. Since the capacitor C2 has been charged, the capacitor C2 forms a loop with the first resistor R11, and the capacitor C2 discharges through the first resistor R11. When the capacitor C2 discharges until its voltage is less than the low threshold in the dual threshold comparator cell, a low level is input to the dual threshold comparator cell, specifically to the comparator U5. After the comparator U5 receives the low level, the output terminal OUT outputs a high level to the semiconductor switch, so that the semiconductor switch Q2 is turned on. In this case, the high output from the comparator U5 pulls the gate of the MOSFET high, turning on the semiconductor switch.
Due to the arranged delay circuit unit, when the voltage across the detection resistor R10 is higher than the high threshold value or lower than the low threshold value, the semiconductor switch can be turned off and turned on within a controllable time by charging and discharging the capacitor C2, for example, the semiconductor switch is turned off rapidly when the voltage across the detection resistor R10 is higher than the high threshold value and is turned on with a delay when the voltage across the detection resistor R10 is lower than the low threshold value, thereby avoiding the semiconductor switch from being turned on frequently, thereby damaging the semiconductor switch.
In the over-current protection circuit according to the present invention, the capacitance of the capacitor C2 is very small, and only a very short time is required to charge the capacitor C2 toA high threshold in the dual threshold comparator unit. And the resistance value of the first resistor R11 connected in parallel with it is larger, for example, the resistance value is 1 MOhm. Thus making it only necessary to enter the protection state 10 -6 Seconds, while a release of the protection state requires a second order, for example 10 0 And seconds. The time difference between the two is close to a million times. Therefore, the semiconductor switch Q2 can be promptly turned off during overcurrent protection. After the semiconductor switch Q2 is turned off, that is, the current in the circuit is 0, the semiconductor switch Q2 can be turned on with a larger delay time based on the first resistor R11 having a larger resistance value.
In addition, in this embodiment, the delay circuit unit may further include a fifth resistor R12 and a first diode D4, and the fifth resistor R12 is disposed between the detection module and the parallel capacitor C2 and the first resistor R11 in series with the first diode D4. The current in the circuit flows to the fifth resistor R12 and the first diode D4 via the detection module, and then to the capacitor C2 via the fifth resistor R12 and the first diode D4. The resistance of the fifth resistor R12 is small, for example, 50 Ohm. This can quickly turn off the semiconductor switch Q2. The first diode D4 ensures that the current from the fifth resistor R12 to the capacitor C2 is conducted, and blocks the capacitor C2 from discharging back to the fifth resistor R12.
In this case, the delay time of turning on the semiconductor switch Q2 and the off time of turning off the semiconductor switch Q2 can be adjusted by changing the resistance values of the first resistor R11 and the fifth resistor R12.
In the embodiment of fig. 1, the dual-threshold comparator unit further includes at least a third resistor R13 and a fourth resistor R15, one end of the third resistor R13 is connected to ground GND and the other end is connected to a non-inverting input terminal of the comparator U5, one end of the fourth resistor R15 is connected to a non-inverting input terminal of the comparator U5 and the other end is connected to the comparator power VCC, and the high threshold value and the low threshold value can be adjusted by setting the resistance value of the second resistor R12, the third resistor R13, or the fourth resistor R15.
The protection threshold value, the protection speed and the time length of time delay can be effectively adjusted by setting the resistance values of the first resistor to the fifth resistor, so that the flexibility of the overcurrent protection circuit is greatly improved.
As can also be seen in fig. 1, the protection circuit module further includes a second diode D6 connected between the output terminal OUT of the comparator U5 and the semiconductor switch, and the second diode D6 is connected in reverse to the output terminal OUT of the comparator U5, so that when the output terminal OUT of the comparator U5 outputs a low level, the second diode D6 is turned on, the gate of the MOSFET is pulled low, and the semiconductor switch Q2 is turned off. When the output terminal OUT of the comparator U5 outputs a high level, the second diode D6 is turned off, the gate of the MOSFET is pulled high, and the semiconductor switch Q2 is turned on.
In the exemplary embodiment shown in fig. 1, a control unit K for controlling the semiconductor switch Q2 in the event of a normal current flow through the semiconductor switch Q2 may additionally be provided for the semiconductor switch Q2.
Fig. 2 shows the operating principle of the comparator U5 of the dual-threshold comparator unit in the overcurrent protection circuit for the semiconductor switch according to the present invention. It can be seen from fig. 2a that when the inverting input terminal of the comparator U5 inputs a high level, for example, the voltage Ui input in fig. 2a is greater than the high threshold V IH The output U of the output OUT of the comparator U5 O Transition from high to low, i.e. from V in the figure OH Is converted into V OL (see the curve in the direction of the arrow in fig. 2 a). When the inverting input terminal of the comparator U5 inputs a low level, for example, the voltage Ui input in FIG. 2b is less than the low threshold V IL The output U of the output OUT of the comparator U5 O Transition from low to high, i.e. from V in the figure OL Is converted into V OH (see the curve in the direction of the arrow in fig. 2 b). The curve in fig. 2c, which is a combination of the curves of fig. 2a and 2b, is represented by the hatching between the curves in fig. 2a and 2b, in the range of which the comparator output will remain unchanged from the previous output, whereby the hysteresis control of the comparator can also be seen.
Fig. 3a and 3c show the operation principle of a single threshold comparator unit in the prior art, and it can be seen from fig. 3a and 3c that the input v of the comparator is I Direct grounding, which is a single threshold comparator, it can be seen from the figure that, for example, the threshold, i.e. the critical current, is present hereThe pressure is zero. When the input v of the comparator I At high level, the output v O At a low level-V sat When input v of the comparator I At low level, the output v O Is high level + V sat . When the input v is not perfectly smooth, but fluctuating I When reduced to zero, there is a small ripple in the zero position, which is at the output v O Causes a very small pulse, after which only the input v I A wider pulse is followed by a true zero crossing. This very small pulse is undesirable and is therefore considered to be a disturbing signal. But since there is only one threshold, the interference signal is unavoidable.
Fig. 3b and 3d show the operating principle of the dual-threshold comparator unit according to the invention, and it can be seen from fig. 3b and 3d that the connection via the resistor R2 between the non-inverting input and the output of the comparator leads to the high threshold value or the low threshold value in fig. 2. As can be seen from FIG. 3b, the glitches traverse the threshold voltage, i.e., the high threshold V, back and forth a number of times TH Or a low threshold value V IH . The interference signal caused by small fluctuations in the zero is in the range between the high threshold and the low threshold, whereby the previous output is kept unchanged in this range, thereby avoiding the interference signal caused by small fluctuations in the zero as in the prior art. Thus, when the output state changes, the output voltage remains stable as in fig. 3b as long as the interfering signal does not exceed the difference Δ U between the high threshold and the low threshold.
Such a dual threshold comparator unit may increase the response speed of the comparator. In addition, since the positive feedback of the dual threshold comparator cell is strong, much stronger than the parasitic coupling in the circuit, the dual threshold comparator cell can also avoid self-oscillation due to the circuit parasitic coupling.
According to the utility model discloses an overcurrent protection circuit for semiconductor switch can break off and switch on semiconductor switch in controllable time under the condition that takes place the short circuit in the circuit, reduces semiconductor switch from this and generates heat, has avoided semiconductor switch frequently to break off and switch on big short-circuit current and suffer damage under the continuous short-circuit situation. In addition, the protection threshold value, the protection speed and the time length of time delay can be effectively adjusted by setting the resistance value of the resistor in the overcurrent protection circuit, so that the flexibility of the overcurrent protection circuit is greatly improved. In addition, the amplifying and filtering circuit can provide a large signal for the post circuit, so that a detection resistor with a very small resistance value is enough, and a plurality of resistors are not required to be arranged in the circuit, thereby saving the structural space and reducing the power consumption.
Furthermore, the overcurrent protection circuit according to the invention can be brought into a protection state quickly, for example 10 -6 Seconds, while a release of the protection state requires a second order, for example 10 0 Second, the time difference between the two is nearly million times. Therefore, the semiconductor switch Q2 can be promptly turned off at the time of overcurrent protection. The semiconductor switch Q2 is turned on with a greater delay after the semiconductor switch Q2 is turned off. Therefore, frequent conduction of short-circuit current is avoided, and damage to the semiconductor switch caused by excessive current is prevented. Finally, by setting double thresholds, namely a high threshold and a low threshold, interference signals in the circuit can be avoided, so that the output voltage is stable.
The specific embodiments described herein are merely illustrative of the spirit of the invention. Those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims.
Claims (10)
1. An overcurrent protection circuit for a semiconductor switch, the overcurrent protection circuit comprising:
a detection module that detects a current flowing in the circuit through the semiconductor switch (Q2) and converts it into a first signal; and
a protection circuit module that receives a first signal from the detection module,
it is characterized in that the preparation method is characterized in that,
the protection circuit module is capable of rapidly controlling the semiconductor switch (Q2) to be turned off when the first signal received from the detection module is higher than a high threshold;
the protection circuit module is capable of controlling the semiconductor switch (Q2) to turn on with a delay when the first signal received from the detection module is below a low threshold, wherein the low threshold is less than the high threshold.
2. Overcurrent protection circuit according to claim 1, characterized in that the detection module comprises a detection resistor (R10) and an amplification filter circuit (80), the detection resistor (R10) detecting the current through the semiconductor switch (Q2) in the circuit, the amplification filter circuit (80) amplifying the voltage across the detection resistor (R10) and sending it as a first signal to the protection circuit module.
3. Overcurrent protection circuit according to claim 1, characterized in that the protection circuit module comprises a delay circuit unit and a dual threshold comparator unit, the delay circuit unit causing the received first signal to reach the dual threshold comparator unit within a controllable time, the dual threshold comparator unit providing a high threshold and a low threshold and comparing the received first signal with the high threshold and the low threshold, respectively, and controlling the switching on and off of the semiconductor switch (Q2) based on the comparison result.
4. The overcurrent protection circuit of claim 3, wherein the delay circuit unit comprises a capacitor (C2) and a first resistor (R11), and the capacitor (C2) and the first resistor (R11) are connected in parallel.
5. The overcurrent protection circuit of claim 3, wherein the dual-threshold comparator unit comprises a comparator (U5) and a second resistor (R14), one end of the second resistor (R14) is connected to the output terminal of the comparator (U5) and the other end of the second resistor (R14) is connected to the non-inverting input terminal of the comparator (U5).
6. The overcurrent protection circuit according to claim 5, wherein the dual-threshold comparator unit further comprises at least a third resistor (R13) and a fourth resistor (R15), the third resistor (R13) having one end connected to Ground (GND) and the other end connected to a non-inverting input of a comparator (U5), the fourth resistor (R15) having one end connected to a non-inverting input of a comparator (U5) and the other end connected to a comparator power supply (VCC), the high threshold and the low threshold being adjustable by changing a resistance value of the second resistor (R14), the third resistor (R13) or the fourth resistor (R15).
7. The overcurrent protection circuit according to claim 4, wherein the delay circuit unit further comprises at least a fifth resistor (R12), the fifth resistor (R12) being connected between the detection module and the parallel circuit of the capacitor (C2) and the first resistor (R11), the delay time for turning on the semiconductor switch (Q2) and the turn-off time for turning off the semiconductor switch (Q2) being adjustable by changing the resistance values of the fifth resistor (R12) and the first resistor (R11).
8. The overcurrent protection circuit of claim 4, wherein the delay circuit unit further comprises a fifth resistor (R12) and a first diode (D4), and the fifth resistor (R12) is arranged in series with the first diode (D4) between the detection module and the parallel capacitor (C2) and the first resistor (R11).
9. The overcurrent protection circuit of claim 1, characterized in that the protection circuit module further comprises a second diode (D6), the second diode (D6) being connected between the semiconductor switch (Q2) and the comparator (U5) and being connected in reverse to the output of the comparator (U5).
10. The overcurrent protection circuit according to claim 8, wherein a resistance value of the fifth resistor (R12) is smaller than a resistance value of the first resistor (R11).
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202122994276.4U CN217388672U (en) | 2021-12-01 | 2021-12-01 | Overcurrent protection circuit for semiconductor switch |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202122994276.4U CN217388672U (en) | 2021-12-01 | 2021-12-01 | Overcurrent protection circuit for semiconductor switch |
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| CN217388672U true CN217388672U (en) | 2022-09-06 |
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