Load short-circuit protection circuit
By designing a load short-circuit protection circuit, using photocouplers and MOS tubes to achieve fast short-circuit protection, the problem of slow response speed of traditional fuses is solved, and the testing efficiency and protection effect are improved.
Patent Information
- Application Number
- CN202411596035.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-11
- Publication Date
- 2025-02-25
AI Technical Summary
During the existing semiconductor testing process, the test circuit adopts traditional fuse short circuit protection, which has a slow response speed and cannot effectively protect the load. It needs to be replaced frequently after damage, which reduces the test efficiency.
A load short circuit protection circuit is designed, including a short circuit monitoring unit, a short circuit protection unit and a start/reset unit. The short-circuit monitoring unit monitors the load short circuit through the photocoupler and sends a signal to the short-circuit protection unit. The short-circuit protection unit uses the MOS tube to cut off the load path for protection, and starts and resets the circuit through the start/reset unit.
It significantly improves the response speed of load short circuit protection, reduces the probability of load damage, and can perform short circuit protection repeatedly, improving the efficiency of semiconductor testing.
Smart Images
Figure CN119518593A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to a load short-circuit protection circuit, belonging to the technical field of short-circuit protection. Background Art
[0002] Short-circuit protection devices play an important role in the field of semiconductor testing. Fast-response short-circuit protection devices can effectively protect the safety of test products.
[0003] With the development of semiconductor testing technology, there are more and more test conditions, and the short-circuit protection requirements for the tested products are getting higher and higher. In the existing semiconductor testing process, most test circuits use traditional fuses, and even a few test circuits are in an unprotected state.
[0004] Traditional fuses cannot effectively protect the load (i.e., the test product) due to their slow short-circuit protection response speed (melting time is about 40ms), and the load needs to be replaced frequently after being damaged, which damages the test product and reduces test efficiency. Summary of the invention
[0005] The object of the present invention is to provide a load short-circuit protection circuit, which can improve the load short-circuit protection speed and reduce load damage.
[0006] In order to achieve the above object, the present invention provides the following technical solutions: A load short-circuit protection circuit, comprising: A short-circuit monitoring unit connected in parallel with the load is used to perform short-circuit monitoring on the load, and when the load is detected to be short-circuited, send a short-circuit protection execution signal to the short-circuit protection unit; A short-circuit protection unit connected in series with the load, used to cut off the path where the load is located according to the short-circuit protection execution signal, and perform short-circuit protection on the load; A start / reset unit connected to the short-circuit protection unit, used to start the load short-circuit protection circuit or reset the load short-circuit protection circuit; Wherein, the first end of the load is connected to the main power supply, and the second end of the load is grounded through the short-circuit protection unit.
[0007] In combination with the first aspect, further, the short-circuit monitoring unit includes a photocoupler, the short-circuit protection unit includes a MOS tube, and the start / reset unit includes a start / reset button switch; the anode of the light-emitting diode in the photocoupler and the first end of the load are commonly connected to the main power supply, the cathode of the light-emitting diode in the photocoupler and the second end of the load are commonly connected to the drain of the MOS tube through a second current-limiting resistor, the emitter of the photodetector in the photocoupler and the second end of the start / reset button switch are commonly connected to the gate of the MOS tube, and the collector of the photodetector in the photocoupler and the first end of the start / reset button switch are commonly connected to the auxiliary power supply through a first current-limiting resistor; the source of the MOS tube is grounded.
[0008] In combination with the first aspect, further, the resistance value of the first current limiting resistor is 1 kΩ; the resistance value of the second current limiting resistor is 1 kΩ.
[0009] In combination with the first aspect, further, the voltage range of the main power supply is +5V to +12V; the voltage range of the secondary power supply is +5V to +12V.
[0010] In combination with the first aspect, further, the circuit further includes: An anti-misstart unit connected to the short-circuit protection unit, used to prevent the load short-circuit protection circuit from misstarting; Wherein, the anti-misstart unit comprises a pull-down resistor, a first end of the pull-down resistor is connected to the gate of the MOS tube, and a second end of the pull-down resistor is connected to the source of the MOS tube.
[0011] In combination with the first aspect, further, the resistance of the pull-down resistor is 100 kΩ.
[0012] In combination with the first aspect, further, the circuit further includes: A short circuit indication unit connected to the load, used to send an indication signal when the load is short-circuited; The short circuit indicating unit comprises a first light emitting diode, an anode of the first light emitting diode is connected to the second end of the load via a third current limiting resistor, and a cathode of the first light emitting diode is grounded.
[0013] In combination with the first aspect, further, the circuit further includes: A short-circuit test unit connected to the short-circuit protection unit, used to cooperate with the short-circuit indication unit to perform a short-circuit test on the load short-circuit protection circuit; Wherein, the short circuit test unit includes a test button switch and a second light-emitting diode, the first end of the test button switch is connected to the second end of the start / reset button switch, and the second end of the test button switch is connected to the source of the MOS tube; the anode of the second light-emitting diode is connected to the main power supply together with the first end of the load through a fourth current limiting resistor, and the cathode of the second light-emitting diode is connected to the second end of the load.
[0014] In combination with the first aspect, further, the resistance of the third current limiting resistor is 1 kΩ.
[0015] In combination with the first aspect, further, the load is connected to the load short-circuit protection circuit through a power strip, a first end of the power strip is connected to a main power supply, and a second end of the power strip is connected to the drain of the MOS tube.
[0016] Compared with the prior art, the present invention has the following beneficial effects: The load short-circuit protection circuit provided by the present invention starts the load short-circuit protection circuit through a start / reset unit, and performs short-circuit monitoring on the load through a short-circuit monitoring unit. When a load short-circuit is detected, a short-circuit protection execution signal is sent to the short-circuit protection unit, and the short-circuit protection unit cuts off the path where the load is located according to the short-circuit protection execution signal to perform short-circuit protection on the load. When the load short-circuit fault is eliminated, the load short-circuit protection circuit is reset through the start / reset unit. Compared with traditional fuses, it can not only improve the load short-circuit protection speed and reduce load damage, but also can repeatedly perform load short-circuit protection. When applied to the field of semiconductor testing, it can effectively protect the test products and improve the test efficiency. BRIEF DESCRIPTION OF THE DRAWINGS
[0017] Figure 1 It is a load short-circuit protection circuit diagram provided by an embodiment of the present invention. DETAILED DESCRIPTION
[0018] The technical solution of the present application is further described in detail below in conjunction with specific implementation methods.
[0019] The embodiments of the present application are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements with the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present application, and should not be construed as limitations on the present application. In the absence of conflict, the embodiments of the present application and the technical features in the embodiments may be combined with each other.
[0020] Embodiment 1: This embodiment provides a load short-circuit protection circuit. Figure 1 As shown, the circuit includes: A short-circuit monitoring unit connected in parallel with the load is used to monitor the load for short circuit, and when a load short circuit is detected, a short-circuit protection execution signal is sent to the short-circuit protection unit; A short-circuit protection unit connected in series with the load is used to cut off the path where the load is located according to the short-circuit protection execution signal, so as to perform short-circuit protection on the load; A start / reset unit connected to the short-circuit protection unit, used to start or reset the load short-circuit protection circuit; The first end of the load is connected to the main power supply, and the second end of the load is grounded through the short-circuit protection unit.
[0021] The load short-circuit protection circuit provided in this embodiment starts the load short-circuit protection circuit through a start / reset unit, and performs short-circuit monitoring on the load through a short-circuit monitoring unit. When a load short-circuit is detected, a short-circuit protection execution signal is sent to the short-circuit protection unit, and the short-circuit protection unit cuts off the path where the load is located according to the short-circuit protection execution signal to perform short-circuit protection on the load. When the load short-circuit fault is eliminated, the load short-circuit protection circuit is reset through the start / reset unit. Compared with traditional fuses, it can not only improve the load short-circuit protection speed and reduce load damage, but also can repeatedly perform load short-circuit protection. When applied to the field of semiconductor testing, it can effectively protect the test products and improve the test efficiency.
[0022] Embodiment 2: This embodiment provides a load short-circuit protection circuit. Based on the embodiment 1, Figure 1 As shown, the short-circuit monitoring unit includes a photocoupler U1, the short-circuit protection unit includes a MOS tube Q1, and the start / reset unit includes a start / reset button switch S / R; the anode of the light-emitting diode in the photocoupler U1 ( Figure 1 Pin 1 of the optocoupler U1 in the middle is connected to the main power supply VCC1 together with the first end of the load. The cathode of the light-emitting diode in the optocoupler U1 ( Figure 1 Pin 2 of the photoelectric coupler U1 is connected to the drain D of the MOS tube Q1 through the second current limiting resistor R2 and the second end of the load. The emitter of the photodetector in the photoelectric coupler U1 ( Figure 1 The pin 3 of the optocoupler U1 in the middle is connected to the second end of the start / reset button switch S / R ( Figure 1 Pin 2 of the start / reset button switch S / R in the middle) is connected to the gate G of the MOS tube Q1 and the collector of the photodetector in the photocoupler U1 ( Figure 1 The first end of the start / reset button switch S / R is connected to the pin 4 of the optocoupler U1 in the middle Figure 1 Pins 1 of the start / reset button switch S / R are connected to the auxiliary power supply VCC2 through the first current limiting resistor R1; the source S of the MOS tube Q1 is grounded. Figure 1In the diagram, GND indicates ground.
[0023] In this embodiment, the first end of the load is connected to the main power supply VCC1, the second end of the load is connected to the drain D of the MOS tube Q1, and the source S of the MOS tube Q1 is grounded to form a main circuit. Figure 1 Pin 3 of the photocoupler U1 is connected to the gate G of the MOS tube Q1 to form a control circuit.
[0024] In the initial state, the MOS tube Q1 is in the off state, the main circuit is not turned on, the light-emitting diode in the photocoupler U1 does not emit light, and the emitter of the photodetector in the photocoupler U1 ( Figure 1 The optocoupler U1 has a pin 3) and a collector ( Figure 1 Pin 4 of the optocoupler U1 is not conducting, and the emitter of the photodetector in U1 ( Figure 1 Pin 3 of the optocoupler U1 cannot provide a trigger voltage to the gate G of the MOS tube Q1, so the MOS tube Q1 needs to be manually triggered to turn it on, that is, before use, the start / reset button switch S / R needs to be pressed first to put the load short-circuit protection circuit into working state.
[0025] When the load is normal, the short-circuit monitoring unit detects that the voltage across the load is normal, that is, the anode of the light-emitting diode in the photocoupler U1 ( Figure 1 The photocoupler U1 pin 1) and the cathode of the light emitting diode in the photocoupler U1 ( Figure 1 There is a potential difference between the pin 2 of the optocoupler U1 and the emitter of the photodetector in the optocoupler U1 ( Figure 1 Pin 3 of the photocoupler U1 in the circuit continuously outputs power to the gate G of the MOS tube Q1, thereby maintaining the main circuit path through the MOS tube Q1, that is, maintaining the path where the load is located.
[0026] When the load is short-circuited, the short-circuit monitoring unit detects that the voltage across the load is 0V, that is, the anode of the light-emitting diode in the photocoupler U1 ( Figure 1 The photocoupler U1 pin 1) and the cathode of the light emitting diode in the photocoupler U1 ( Figure 1 The potential of the pin 2 of the optocoupler U1 is equal, and the emitter of the photodetector in the optocoupler U1 ( Figure 1 Pin 3 of the photocoupler U1 stops outputting within 5μs, i.e., cuts off the power supply to the gate G of the MOS tube Q1. The MOS tube Q1 cuts off the main circuit within 6ns, i.e., cuts off the path where the load is located.
[0027] In this embodiment, the photocoupler U1 cuts off the power supply to the MOS tube Q1, which is a short-circuit protection execution signal sent by the short-circuit monitoring unit to the short-circuit protection unit. The short-circuit protection execution signal is an electrical signal, that is, the emitter of the photodetector in the photocoupler U1 ( Figure 1 The voltage transmitted from pin 3 of the optocoupler U1 to the gate G of the MOS tube Q1 is 0V.
[0028] The load short-circuit protection circuit provided in this embodiment converts the electrical signal into an internal optical signal through the photocoupler U1, thereby isolating the main circuit from the control circuit, so that the control circuit is not affected by the main circuit.
[0029] The photocoupler U1 can cut off the power supply to the MOS tube Q1 within 5μs, and the MOS tube Q1 can cut off the main circuit within 6ns. Compared with the traditional fuse with a melting time of about 40ms, the load short-circuit protection circuit provided in this embodiment has significantly improved the overall response speed of the load short-circuit protection.
[0030] Embodiment 3: This embodiment provides a load short-circuit protection circuit. Based on Embodiment 2, the resistance value of the first current limiting resistor R1 is 1 kΩ; the resistance value of the second current limiting resistor R2 is 1 kΩ.
[0031] Embodiment 4: This embodiment provides a load short-circuit protection circuit. Based on Embodiment 2, the voltage range of the main power supply VCC1 is +5V to +12V; the voltage range of the auxiliary power supply VCC2 is +5V to +12V.
[0032] In this embodiment, the maximum current of the load short-circuit protection circuit is 49A.
[0033] Embodiment 5: This embodiment provides a load short-circuit protection circuit. Based on Embodiment 2, the circuit further includes: an anti-misstart unit connected to the short-circuit protection unit, for preventing the load short-circuit protection circuit from misstarting.
[0034] In this embodiment, Figure 1 As shown, the false start prevention unit includes a pull-down resistor R3, a first end of the pull-down resistor R3 is connected to the gate G of the MOS transistor Q1, and a second end of the pull-down resistor R3 is connected to the source S of the MOS transistor Q1.
[0035] The load short-circuit protection circuit provided in this embodiment prevents the load short-circuit protection circuit from being mistakenly started by means of the anti-misstart unit.
[0036] Embodiment 6: This embodiment provides a load short-circuit protection circuit. Based on Embodiment 5, the resistance of the pull-down resistor R3 is 100 kΩ.
[0037] Embodiment 7: This embodiment provides a load short-circuit protection circuit. Based on Embodiment 2, the circuit further includes: a short-circuit indication unit connected to the load, for issuing an indication signal when the load is short-circuited.
[0038] In this embodiment, Figure 1 As shown, the short circuit indicating unit includes a first light emitting diode LED1, an anode of the first light emitting diode LED1 is connected to the second end of the load through a third current limiting resistor R4, and a cathode of the first light emitting diode LED1 is grounded.
[0039] When the load is normal, the voltage provided by the main power supply VCC1 is applied to the third current limiting resistor R4 after load voltage division. Under the current limiting effect of the third current limiting resistor R4, the current cannot reach the first light emitting diode LED1, and the first light emitting diode LED1 does not emit light.
[0040] When the load is short-circuited, the voltage provided by the main power supply VCC1 is directly applied to the third current limiting resistor R4. The third current limiting resistor R4 is insufficient to limit the current, and the current reaches the first light-emitting diode LED1, and the first light-emitting diode LED1 emits light.
[0041] The load short-circuit protection circuit provided in this embodiment indicates a load short circuit by emitting light through the first light-emitting diode LED1, and provides short-circuit indication while providing short-circuit protection, which can facilitate the detection of load short circuits and timely eliminate load short-circuit faults.
[0042] Embodiment 8: This embodiment provides a load short-circuit protection circuit. Based on Embodiment 7, the circuit further includes: a short-circuit test unit connected to the short-circuit protection unit, which is used to cooperate with the short-circuit indication unit to perform a short-circuit test on the load short-circuit protection circuit.
[0043] In this embodiment, Figure 1 As shown, the short circuit test unit includes a test button switch TEST and a second light emitting diode LED2, a first end of the test button switch TEST ( Figure 1 Connect the pin 1 of the test button switch TEST to the second end of the start / reset button switch S / R ( Figure 1 Pin 2 of the start / reset push button switch S / R), the second end of the test push button switch TEST ( Figure 1 Pin 2 of the test button switch TEST is connected to the source S of the MOS tube Q1; the anode of the second light-emitting diode LED2 is connected to the main power supply VCC1 through the fourth current limiting resistor R5 and the first end of the load, and the cathode of the second light-emitting diode LED2 is connected to the second end of the load.
[0044] When performing a short-circuit test on the load short-circuit protection circuit before connecting the load, first press the start / reset button switch S / R to put the load short-circuit protection circuit into working state, and observe the second light-emitting diode LED2. If the second light-emitting diode LED2 is lit, press the test button switch TEST to short-circuit the load short-circuit protection circuit, and observe the second light-emitting diode LED2 and the first light-emitting diode LED1 at the same time. If the second light-emitting diode LED2 does not emit light and the first light-emitting diode LED1 is lit, it indicates that the load short-circuit protection circuit functions normally and the short-circuit test is completed.
[0045] The load short-circuit protection circuit provided in this embodiment performs a short-circuit test on the load short-circuit protection circuit through the cooperation of the short-circuit testing unit and the short-circuit indicating unit to ensure that the load short-circuit protection circuit functions normally.
[0046] Embodiment 9: This embodiment provides a load short-circuit protection circuit. Based on Embodiment 7 or Embodiment 8, the resistance of the third current limiting resistor is 1 kΩ.
[0047] Embodiment 10: This embodiment provides a load short-circuit protection circuit. Based on Embodiment 2, Figure 1 As shown, the load is connected to the load short-circuit protection circuit through the power strip H1. The first end of the power strip H1 ( Figure 1 Pin 1 of the middle power strip H1 is connected to the main power supply VCC1, and the second end of the power strip H1 ( Figure 1 Pin 2 of the middle power strip H1 is connected to the drain D of the MOS tube Q1.
[0048] In this embodiment, the load is inserted into the power strip H1 so that the first end of the load passes through the first end of the power strip H1 ( Figure 1 Pin 1 of the middle power strip H1 is connected to the main power supply VCC1, and the second end of the load is connected to the second end of the power strip H1 ( Figure 1 Pin 2 of the middle power strip H1 is connected to the drain D of the MOS tube Q1.
[0049] In the load short-circuit protection circuit provided in this embodiment, the load is connected to the load short-circuit protection circuit through the power strip H1. When the load is short-circuited, the short-circuited load can be directly removed from the power strip H1 to eliminate the short-circuit fault, or when the load is tested, the tested load can be directly removed from the power strip H1 and replaced with the next load for testing. When applied to the field of semiconductor testing, it is easy to replace the load and improve the testing efficiency.
[0050] Embodiment 11: The present embodiment provides a load short-circuit protection circuit. The load short-circuit protection circuit provided in the present embodiment is a combination of Embodiments 1 to 10, that is, it includes a short-circuit monitoring unit, a short-circuit protection unit, a start / reset unit, an anti-misstart unit, a short-circuit indication unit and a short-circuit test unit.
[0051] In this embodiment, the use of the load short-circuit protection circuit specifically includes the following steps: Step 1: Press the start / reset button switch S / R to put the load short-circuit protection circuit into working state, and observe the second light-emitting diode LED2. If the second light-emitting diode LED2 is lit, go to step 2; Step 2: Press the test button switch TEST to short-circuit the load short-circuit protection circuit, and observe the second light-emitting diode LED2 and the first light-emitting diode LED1 at the same time. If the second light-emitting diode LED2 does not emit light and the first light-emitting diode LED1 emits light, it means that the load short-circuit protection circuit functions normally and the short-circuit test is completed; Step 3: Press the start / reset button switch S / R again to put the load short-circuit protection circuit into use; Step 4: Plug the load into socket H1; Step 5: When the load is short-circuited, the emitter of the photodetector in optocoupler U1 ( Figure 1 Pin 3 of the photoelectric coupler U1 cuts off the power supply to the gate G of the MOS tube Q1 within 5μs, the MOS tube Q1 cuts off the path where the load is located within 6ns, and the first light-emitting diode LED1 emits light; Step 6: Remove the short-circuited load from socket H1 to eliminate the short-circuit fault and then reinsert it into socket H1; Step 7: Press the start / reset button switch S / R again to force the gate G of the MOS tube Q1 to be powered, so that the MOS tube Q1 remains in a saturated conduction state and continues to test the load; Step 8: Remove the tested load from socket H1 and replace it with the next load for testing.
[0052] The load short-circuit protection circuit provided in this embodiment, when applied in the field of semiconductor testing, can effectively protect the tested product, reduce damage to the tested product, and improve test efficiency.
[0053] The above are only preferred implementations of the present application. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present application. These improvements and modifications should also be regarded as the scope of protection of the present application.
Claims
1. A load short-circuit protection circuit, characterized in that: include: A short-circuit monitoring unit connected in parallel with the load is used to perform short-circuit monitoring on the load, and when a short circuit is detected in the load, a short-circuit protection execution signal is sent to the short-circuit protection unit; A short-circuit protection unit connected in series with the load, used to cut off the path where the load is located according to the short-circuit protection execution signal, and perform short-circuit protection on the load; A start / reset unit connected to the short-circuit protection unit, used to start the load short-circuit protection circuit or reset the load short-circuit protection circuit; Wherein, the first end of the load is connected to the main power supply, and the second end of the load is grounded through the short-circuit protection unit.
2. The load short-circuit protection circuit according to claim 1, characterized in that: The short-circuit monitoring unit includes a photoelectric coupler, the short-circuit protection unit includes a MOS tube, and the start / reset unit includes a start / reset button switch; the anode of the light-emitting diode in the photoelectric coupler and the first end of the load are connected to the main power supply, the cathode of the light-emitting diode in the photoelectric coupler and the second end of the load are connected to the drain of the MOS tube through a second current-limiting resistor, the emitter of the photodetector in the photoelectric coupler and the second end of the start / reset button switch are connected to the gate of the MOS tube, and the collector of the photodetector in the photoelectric coupler and the first end of the start / reset button switch are connected to the auxiliary power supply through a first current-limiting resistor; the source of the MOS tube is grounded.
3. The load short-circuit protection circuit according to claim 2, characterized in that: The resistance value of the first current limiting resistor is 1 kΩ; the resistance value of the second current limiting resistor is 1 kΩ.
4. The load short-circuit protection circuit according to claim 2, characterized in that: The voltage range of the main power supply is +5V to +12V; the voltage range of the auxiliary power supply is +5V to +12V.
5. The load short-circuit protection circuit according to claim 2, characterized in that: Also includes: An anti-misstart unit connected to the short-circuit protection unit, used to prevent the load short-circuit protection circuit from misstarting; Wherein, the anti-misstart unit comprises a pull-down resistor, a first end of the pull-down resistor is connected to the gate of the MOS tube, and a second end of the pull-down resistor is connected to the source of the MOS tube.
6. The load short-circuit protection circuit according to claim 5, characterized in that: The resistance of the pull-down resistor is 100 kΩ.
7. The load short-circuit protection circuit according to claim 2, characterized in that: Also includes: A short circuit indication unit connected to the load, used to send an indication signal when the load is short-circuited; The short circuit indicating unit comprises a first light emitting diode, an anode of the first light emitting diode is connected to the second end of the load via a third current limiting resistor, and a cathode of the first light emitting diode is grounded.
8. The load short-circuit protection circuit according to claim 7, characterized in that: Also includes: A short-circuit test unit connected to the short-circuit protection unit, used to cooperate with the short-circuit indication unit to perform a short-circuit test on the load short-circuit protection circuit; Wherein, the short circuit test unit comprises a test button switch and a second light emitting diode, the first end of the test button switch is connected to the second end of the start / reset button switch, and the second end of the test button switch is connected to the source of the MOS tube; The anode of the second light emitting diode is connected to the main power supply together with the first end of the load through the fourth current limiting resistor, and the cathode of the second light emitting diode is connected to the second end of the load.
9. The load short-circuit protection circuit according to claim 7 or 8, characterized in that: The resistance of the third current limiting resistor is 1 kΩ.
10. The load short-circuit protection circuit according to claim 2, characterized in that: The load is connected to the load short-circuit protection circuit through a power strip, a first end of the power strip is connected to a main power supply, and a second end of the power strip is connected to a drain of the MOS tube.