Protection Circuit for High-Temperature Reverse Bias Test Circuit

Abstract

The present invention provides a protection circuit for a high-temperature reverse bias test circuit. The test circuit includes a device power supply, a current-limiting resistor, a fuse, and a test diode. The protection circuit includes: a current signal acquisition unit, which is connected to the test circuit and is used to acquire the current value; a constant current protection circuit; and a control circuit, which is respectively connected to the test circuit, the current signal acquisition unit, and the constant current protection circuit. The control circuit controls the constant current protection circuit to be connected to the test circuit according to the current value acquired by the current signal acquisition unit when the test diode is in a failure state, so as to perform constant current protection. The present invention can effectively protect the high-temperature reverse bias test circuit. The protection circuit of the present invention has a simple structure, convenient design, strong usability, and low cost, and the protection circuit has a self-recovery ability and can operate immediately after replacing the failed device, and the maintenance is simple.

Description

Technical Field

[0001] The present invention relates to the technical field of circuit protection, and particularly relates to a protection circuit for a high-temperature reverse bias test circuit. Background Art

[0002] At present, a current-limiting resistor and a fuse are connected in series in the test device circuit of a high-temperature reverse bias device, aiming to prevent damage to the power supply and the device when the device fails. The current-limiting range of the current-limiting resistor does not exceed the fuse melting value. When the device fails, the current-limiting resistor also undertakes the role of voltage division. At this time, its power is amplified sharply, making the resistor easily burned out and even further causing serious damage to the device. Summary of the Invention

[0003] The present invention provides a protection circuit for a high-temperature reverse bias test circuit to solve the technical problem that the test device of the current high-temperature reverse bias device is easily damaged.

[0004] The technical solution adopted by the present invention is as follows:

[0005] A protection circuit for a high-temperature reverse bias test circuit, the test circuit includes a device power supply, a current-limiting resistor, a fuse, and a test diode. The protection circuit includes: a current signal acquisition unit connected to the test circuit, and the current signal acquisition unit is used to acquire a current value; a constant current protection circuit; a control circuit connected to the test circuit, the current signal acquisition unit, and the constant current protection circuit respectively. The control circuit controls the constant current protection circuit to be connected to the test circuit according to the current value acquired by the current signal acquisition unit when the test diode is in a failure state, so as to perform constant current protection.

[0006] Wherein, the anode of the test diode is connected to the negative pole of the device power supply, one end of the fuse is connected to the cathode of the test diode, and the other end of the fuse is connected to one end of the current-limiting resistor.

[0007] The control circuit includes: a first relay, one end of the coil of the first relay is connected to the positive pole of the device power supply; a second relay, one end of the coil of the second relay is connected to the first contact of the first relay, the first contact of the second relay is connected to the other end of the coil of the first relay, and the second contact of the second relay is connected to the other end of the current-limiting resistor; a first adjusting resistor, one end of the first adjusting resistor is connected to the second contact of the first relay; a control power supply, the positive pole of the control power supply is connected to the other end of the first adjusting resistor, and the negative pole of the control power supply is connected to the other end of the coil of the second relay.

[0008] The control circuit further includes: a first voltage stabilizing diode, the cathode of the first voltage stabilizing diode is connected to one end of the coil of the first relay, and the anode of the first voltage stabilizing diode is connected to the other end of the coil of the first relay; a second voltage stabilizing diode, the cathode of the second voltage stabilizing diode is connected to one end of the coil of the second relay, and the anode of the second voltage stabilizing diode is connected to the other end of the coil of the second relay.

[0009] The constant current protection circuit includes: a triode, the base of the triode is connected to the positive pole of the control power supply, and the collector of the triode is connected to the third contact of the second relay; a second adjusting resistor, one end of the second adjusting resistor is connected to the negative pole of the control power supply, and the other end of the second adjusting resistor is connected to the emitter of the triode; a protection resistor, one end of the protection resistor is connected to the emitter of the triode, and the other end of the protection resistor is connected to the other end of the fuse.

[0010] The current signal acquisition unit includes a sampling resistor, and the sampling resistor is connected in parallel with the coil of the first relay.

[0011] The first relay is a normally closed relay.

[0012] The first relay is a conversion type relay, the second contact of the first relay is a moving contact, the first contact of the first relay is a normally closed contact, and the normally open contact of the first relay is left floating.

[0013] The second relay is a conversion type relay, the first contact of the second relay is a moving contact, the second contact of the second relay is a normally open contact, and the third contact of the second relay is a normally closed contact.

[0014] Advantages of the present invention:

[0015] By providing a current signal acquisition unit, a constant current protection circuit and a control circuit, the control circuit can control the constant current protection circuit to be connected to the test circuit according to the current value collected by the current signal acquisition unit when the test diode is in a failure state for constant current protection. Thus, effective protection for the high-temperature reverse bias test circuit can be achieved. The protection circuit has a simple structure, convenient design, strong usability, low cost, and has a self-recovery ability. It can operate immediately after replacing the failed device, and the maintenance is simple. Description of the Drawings

[0016] Figure 1 It is a block diagram of the protection circuit of the high-temperature reverse bias test circuit according to an embodiment of the present invention;

[0017] Figure 2Circuit diagram of the protection circuit of the high-temperature reverse bias test circuit according to an embodiment of the present invention;

[0018] Figure 3 Equivalent circuit diagram of the protection circuit when the test diode is in the test state according to an embodiment of the present invention;

[0019] Figure 4 Equivalent circuit diagram of the protection circuit when the test diode is in the failure state according to an embodiment of the present invention. Detailed implementation manners

[0020] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0021] Next, the protection circuit of the high-temperature reverse bias test circuit according to the embodiment of the present invention will be described in conjunction with the accompanying drawings.

[0022] The test circuit of the embodiment of the present invention may include a device power supply, a current-limiting resistor, a fuse, and a test diode. As Figure 1 shown, the protection circuit includes a current signal acquisition unit 10, a constant current protection circuit 20, and a control circuit 30.

[0023] Among them, the current signal acquisition unit 10 is connected to the test circuit, and the current signal acquisition unit 10 is used to acquire the current value; the control circuit 30 is respectively connected to the test circuit, the current signal acquisition unit 10, and the constant current protection circuit 20. The control circuit 30 can control the constant current protection circuit 20 to be connected to the test circuit according to the current value acquired by the current signal acquisition unit 10 when the test diode is in the failure state, so as to perform constant current protection.

[0024] As Figure 2 shown, the anode of the test diode D1 is connected to the negative pole of the device power supply, one end of the fuse FUSE is connected to the cathode of the test diode D1, and the other end of the fuse FUSE is connected to one end of the current-limiting resistor R1.

[0025] In an embodiment of the present invention, as Figure 2As shown, the control circuit 30 includes a first relay J1, a second relay J2, a first adjusting resistor R2, and a control power supply U1. Among them, one end of the coil of the first relay J1 is connected to the positive pole of the device power supply; one end of the coil of the second relay J2 is connected to the first contact of the first relay J1, the first contact of the second relay J2 is connected to the other end of the coil of the first relay J1, and the second contact of the second relay J2 is connected to the other end of the current-limiting resistor R1; one end of the first adjusting resistor R2 is connected to the second contact of the first relay J1; the positive pole of the control power supply U1 is connected to the other end of the first adjusting resistor R2, and the negative pole of the control power supply U1 is connected to the other end of the coil of the second relay J2.

[0026] Further, as Figure 2 shown, the control circuit 30 may further include a first voltage stabilizing diode D2 and a second voltage stabilizing diode D3. The cathode of the first voltage stabilizing diode D2 is connected to one end of the coil of the first relay J1, and the anode of the first voltage stabilizing diode D2 is connected to the other end of the coil of the first relay J1; the cathode of the second voltage stabilizing diode D3 is connected to one end of the coil of the second relay J2, and the anode of the second voltage stabilizing diode D3 is connected to the other end of the coil of the second relay J2.

[0027] In an embodiment of the present invention, as Figure 2 shown, the constant current protection circuit 20 includes a triode Q1, a second adjusting resistor R3, and a protection resistor R4. Among them, the base of the triode Q1 is connected to the positive pole of the control power supply U1, and the collector of the triode Q1 is connected to the third contact of the second relay J2; one end of the second adjusting resistor R3 is connected to the negative pole of the control power supply U1, and the other end of the second adjusting resistor R3 is connected to the emitter of the triode Q1; one end of the protection resistor R4 is connected to the emitter of the triode Q1, and the other end of the protection resistor R4 is connected to the other end of the fuse FUSE.

[0028] In an embodiment of the present invention, as Figure 2 shown, the current signal acquisition unit 10 includes a sampling resistor R5, and the sampling resistor R5 is connected in parallel with the coil of the first relay J1.

[0029] In the above protection circuit, when current passes through the sampling resistor R5, the voltage across the sampling resistor R5 changes, and its voltage can drive the first relay J1 and further act on the control circuit 30. The first adjusting resistor R2, the first voltage stabilizing diode D2, and the second voltage stabilizing diode D3 can play a role in protecting the relay. By changing the resistance value of the second adjusting resistor R3, the base current of the triode Q1 can be changed, and the collector current of the triode Q1 can be adjusted to keep the current in the circuit within a stable range. The protection resistor R4 is a high-power resistor and can play a role in voltage division and current limiting.

[0030] In one embodiment of the present invention, the first relay J1 may be a normally closed relay.

[0031] In one embodiment of the present invention, both the first relay J1 and the second relay J2 may be transfer relays. Figure 2 That is, taking both the first relay J1 and the second relay J2 as transfer relays as an example. As Figure 2 shown, the second contact of the first relay J1 is a moving contact, the first contact of the first relay J1 is a normally closed contact, and the normally open contact of the first relay J1 is floating; the first contact of the second relay J2 is a moving contact, the second contact of the second relay J2 is a normally open contact, and the third contact of the second relay J2 is a normally closed contact.

[0032] When the test diode D1 is in a normal test state, the test diode D1 is in a reverse cut-off state, the current in the circuit is extremely small, the first relay J1 connects to the control circuit 30, the control power supply U1 drives the second relay J2 to work. At this time, the device power supply is connected to the switch of the second relay J2 through the coil of the first relay J1, and the switch of the second relay J2 connects to the current-limiting resistor R1. The current-limiting resistor R1, the fuse FUSE, and the test diode D1 are connected in series to form a closed loop. The equivalent circuit diagram is as Figure 3 shown.

[0033] When the test diode D1 is in a failure state during the test, the current in the above-mentioned closed loop continuously increases, and the voltage on the coil of the first relay J1 gradually increases. When the current in the circuit reaches the set value, the first relay J1 is driven by the voltage, and the switch of the first relay J1 disconnects from the control circuit. The second relay J2 in the control circuit loses the voltage drive. The switch of the second relay J2 connects to the triode Q1, and the triode Q1 conducts under the drive of the control power supply U1. It connects the protection resistor R4, the fuse FUSE, and the test diode D1 to form a closed loop. The equivalent circuit diagram is as Figure 4 shown. At this time, the collector current of the triode is controlled by the base current, and the current in the circuit no longer increases, reaching a constant current protection state.

[0034] According to the protection circuit of the high-temperature reverse bias test circuit of the embodiment of the present invention, by setting a current signal acquisition unit, a constant current protection circuit, and a control circuit, the control circuit can control the constant current protection circuit to connect to the test circuit according to the current value collected by the current signal acquisition unit when the test diode is in a failure state for constant current protection. Thus, effective protection of the high-temperature reverse bias test circuit can be achieved. The protection circuit has a simple structure, convenient design, strong usability, and low cost. Moreover, the protection circuit has a self-recovery ability and can operate after replacing the failed device, and the maintenance is simple.

[0035] In the description of the present invention, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include one or more of such features. The meaning of "a plurality" is two or more unless otherwise specifically defined.

[0036] In the present invention, unless otherwise clearly defined and limited, the terms "mounted", "connected", "coupled", "fixed", etc. shall be construed broadly. For example, it may be a fixed connection, a detachable connection, or integrated; it may be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium, and it may be the internal communication of two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0037] In the present invention, unless otherwise clearly defined and limited, the first feature being "on" or "under" the second feature may be that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, the first feature being "above", "over" and "on top of" the second feature may be that the first feature is directly above or obliquely above the second feature, or merely indicates that the first feature has a higher horizontal height than the second feature. The first feature being "under", "beneath" and "underneath" the second feature may be that the first feature is directly below or obliquely below the second feature, or merely indicates that the first feature has a lower horizontal height than the second feature.

[0038] In the description of this specification, the descriptions referring to terms such as "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. mean that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in a suitable manner in any one or more embodiments or examples. In addition, without contradiction, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples.

[0039] Although the embodiments of the present invention have been shown and described, for those of ordinary skill in the art, it can be understood that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A protection circuit for a high-temperature reverse bias test circuit, characterized in that, The test circuit includes a device power supply, a current-limiting resistor, a fuse, and a test diode, and the protection circuit includes: a current signal acquisition unit, which is connected to the test circuit and is used to acquire the current value; a constant-current protection circuit; a control circuit, which is respectively connected to the test circuit, the current signal acquisition unit, and the constant-current protection circuit. The control circuit controls the constant-current protection circuit to be connected to the test circuit for constant-current protection according to the current value acquired by the current signal acquisition unit when the test diode is in a failure state; the anode of the test diode is connected to the negative pole of the device power supply, one end of the fuse is connected to the cathode of the test diode, and the other end of the fuse is connected to one end of the current-limiting resistor; the control circuit includes: a first relay, one end of the coil of the first relay is connected to the positive pole of the device power supply; a second relay, one end of the coil of the second relay is connected to the first contact of the first relay, the first contact of the second relay is connected to the other end of the coil of the first relay, and the second contact of the second relay is connected to the other end of the current-limiting resistor; a first adjusting resistor, one end of the first adjusting resistor is connected to the second contact of the first relay; a control power supply, the positive pole of the control power supply is connected to the other end of the first adjusting resistor, and the negative pole of the control power supply is connected to the other end of the coil of the second relay; the constant-current protection circuit includes: a triode, the base of the triode is connected to the positive pole of the control power supply, and the collector of the triode is connected to the third contact of the second relay; a second adjusting resistor, one end of the second adjusting resistor is connected to the negative pole of the control power supply, and the other end of the second adjusting resistor is connected to the emitter of the triode; a protection resistor, one end of the protection resistor is connected to the emitter of the triode, and the other end of the protection resistor is connected to the other end of the fuse; the current signal acquisition unit includes a sampling resistor, and the sampling resistor is connected in parallel with the coil of the first relay.

2. The protection circuit for a high-temperature reverse bias test circuit according to claim 1, characterized in that, The control circuit further includes: a first zener diode, the cathode of the first zener diode is connected to one end of the coil of the first relay, and the anode of the first zener diode is connected to the other end of the coil of the first relay; a second zener diode, the cathode of the second zener diode is connected to one end of the coil of the second relay, and the anode of the second zener diode is connected to the other end of the coil of the second relay.

3. The protection circuit for a high-temperature reverse bias test circuit according to claim 1, characterized in that, The first relay is a normally closed relay.

4. The protection circuit for a high-temperature reverse bias test circuit according to claim 1, characterized in that, The first relay is a conversion-type relay, the second contact of the first relay is a moving contact, the first contact of the first relay is a normally closed contact, and the normally open contact of the first relay is left floating.

5. The protection circuit for a high-temperature reverse bias test circuit according to claim 1, characterized in that, The second relay is a conversion-type relay, the first contact of the second relay is a moving contact, the second contact of the second relay is a normally open contact, and the third contact of the second relay is a normally closed contact.

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