CN203289091U - Overcurrent protection circuit - Google Patents
Overcurrent protection circuit Download PDFInfo
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- CN203289091U CN203289091U CN2013202826318U CN201320282631U CN203289091U CN 203289091 U CN203289091 U CN 203289091U CN 2013202826318 U CN2013202826318 U CN 2013202826318U CN 201320282631 U CN201320282631 U CN 201320282631U CN 203289091 U CN203289091 U CN 203289091U
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Abstract
The utility model relates to an overcurrent protection circuit which comprises a power-side terminal, a load side and a controllable shunting loop of a main loop, wherein the controllable shunting loop is connected between a power side and the load side in parallel. The controllable shunting loop comprises a shunting resistor and a shunting control switch, wherein the shunting control switch is connected in series at least at one end of the shunting resistor. According to the utility model, the controllable shunting loop is connected in parallel with the main loop between the power side and the load side; the shunting resistor and the shunting control switch in the controllable shunting loop are used to protect the circuit; when a load loop is short-circuited or has other faults, the shunting control switch is automatically switched on and the controllable shunting loop works to decrease the current passing the load loop to realize overcurrent protection; and when the load current resumes to a normal value, the shunting control switch is automatically switched off, an electrical loop can be used normally, and the circuit can automatically returns to operation.
Description
Technical field
The utility model relates to a kind of current foldback circuit, belongs to electric equipment resist technology field.
Background technology
At present, fuse protection is adopted in the overcurrent protection in circuit more, in case fuse protection, after needing to change fuse, circuit can recover again, and impact is produced or used.
The utility model content
The purpose of this utility model is to provide a kind of current foldback circuit, to solve the problem of existing electric equipment because adopting the fuse protection circuit automatically to recover.
The utility model provides a kind of current foldback circuit for solving the problems of the technologies described above; this current foldback circuit comprise mains side terminals, load-side and be attempted by mains side and the load-side major loop on controlled shunting circuit, this controlled shunting circuit comprises shunt resistance and at least at the flow-dividing control switch of shunt resistance one end serial connection.
Described flow-dividing control switch is a NPN type triode, the collector and emitter of this triode is serially connected in described controlled shunting circuit, collector electrode is connected with an end of shunt resistance, emitter is connected with terminals of mains side, and the base stage of triode is connected with the major loop between mains side and load-side.
Be serially connected with sample resistance between the emitter of described triode and base stage.
Described controlled shunting circuit also comprises a diode, and the negative electrode of diode is connected with an end of shunt resistance, and anode is connected with terminals of mains side.
The beneficial effects of the utility model are: the utility model is by on the major loop between mains side and load-side and connect a controlled shunting circuit; utilize shunt resistance and flow-dividing control switch in controlled shunting circuit to protect circuit; when load circuit short circuit or other fault; the flow-dividing control switch is opened automatically; controlled shunting circuit work; the electric current that flows through in load circuit is reduced; realize overcurrent protection; when load current recovers normal value; the flow-dividing control switch cuts out automatically; electric loop can normally use, and circuit can resume operation automatically.
Description of drawings
Fig. 1 is the system construction drawing of the utility model AC/DC overcurrent protection circuit;
Fig. 2 is the circuit structure diagram of the AC/DC overcurrent protection circuit in the utility model embodiment one;
Fig. 3 is the circuit structure diagram of AC/DC overcurrent protection circuit in the utility model embodiment two;
Fig. 4 is the circuit structure diagram of AC/DC overcurrent protection circuit in the utility model embodiment three;
Fig. 5 is the circuit structure diagram of AC/DC overcurrent protection circuit in the utility model embodiment four.
Embodiment
As shown in Figure 1; this current foldback circuit of current foldback circuit of the present utility model comprise mains side terminals, load-side and be attempted by mains side and the load-side major loop on controlled shunting circuit, this controlled shunting circuit comprises shunt resistance and at least at the flow-dividing control switch of shunt resistance one end serial connection.When load circuit short circuit or other fault; the flow-dividing control switch is opened automatically; controlled shunting circuit work; the electric current that flows through in load circuit is reduced; realize overcurrent protection, when load current recovered normal value, the flow-dividing control switch cut out automatically; electric loop can normally use, and whole circuit resumes operation automatically.
Embodiment one
as shown in Figure 2, current foldback circuit of the present utility model comprises power supply J1, shunt resistance R3, triode Q2, with load J2, the binding post 2 of power supply J1 is for just, 1 for negative, triode Q2 is NPN switching mode triode, form load circuit by power supply J1 and load J2 serial connection, on the major loop between load J2 and power supply J1 and be connected to controlled shunting circuit, this controlled shunting circuit is formed by shunt resistance R3 and triode Q2 serial connection, the end of shunt resistance R3 is connected with the binding post 2 of power supply J1, the other end of shunt resistance R3 is connected with the collector electrode of triode Q2, the emitter of triode Q2 is connected with the binding post 1 of power supply J1, the base stage of triode Q2 is connected with the major loop between load J2 and power supply J1.
Its operation principle is as follows:
In DC loop, when load current during less than the setup parameter value, because electric current is less, voltage is less than the required base voltage of Q2 triode conducting, and not conducting of Q2, protect R3 and Q2 in loop not to work, whole loop current flows to: power supply+à load à power supply-and, be in normal operating conditions; When load current during greater than the setup parameter value; because electric current is larger; voltage is greater than the required base voltage of Q2 triode conducting; the Q2 conducting; R3 in the protection loop and Q2 work; make its whole current circuit be divided into two-way, wherein the current circuit of major loop is: power supply+à load à power supply-, the current circuit of controlled shunting circuit is: power supply+à R3 à Q2 à power supply-.
Embodiment two
as shown in Figure 3, protective circuit of the present utility model comprises power supply J1, shunt resistance R3, triode Q2, sample resistance R2 and load J2, the binding post 2 of power supply J1 is for just, 1 for negative, triode Q2 is NPN switching mode triode, form major loop by power supply J1 and load J2 serial connection, on major loop and be connected to by shunt resistance R3, the controlled shunting circuit that triode Q2 and sample resistance R2 form, the binding post 2 of power supply J1 is connected with the end of shunt resistance R3, the other end of shunt resistance R3 is connected with the collector electrode of triode Q2, the emitter of triode Q2 is connected with the binding post 1 of power supply J1, the base stage of triode Q2 is connected with the major loop between load J2 and power supply J1, be serially connected with sample resistance R2 between the emitter of triode Q2 and base stage.
Its operation principle is as follows:
In DC loop, when load current during less than the setup parameter value, because electric current is less, voltage is less than the required base voltage of Q2 triode conducting, not conducting of Q2, R3 and Q2 in the protection loop do not work, and whole loop current flows to and is: power supply+à load à R2 à power supply-,, be in normal operating conditions; When load current during greater than the setup parameter value; because electric current is larger; voltage is greater than the required base voltage of Q2 triode conducting; the Q2 conducting; R3 in the protection loop and Q2 work, make its whole current circuit be divided into two-way, and wherein the current circuit of major loop is: power supply+à load à R2 à power supply-; the current circuit of controlled shunting circuit is: power supply+à R3 à Q2 à power supply-and, circuit can recover automatically.
Embodiment three
as shown in Figure 4, protective circuit of the present utility model comprises power supply J1, diode D1, shunt resistance R3, triode Q2, sample resistance R2 and load J2, the binding post 2 of power supply J1 is for just, 1 for negative, triode Q2 is NPN switching mode triode, form major loop by power supply J1 and load J2 serial connection, on major loop and be connected to by diode D1, shunt resistance R3, the controlled shunting circuit that triode Q2 and sample resistance R2 form, the anode of diode D1 is connected with the binding post 2 of power supply J1, the negative electrode of diode D1 is connected with the end of shunt resistance R3, the other end of shunt resistance R3 is connected with the collector electrode of triode Q2, the emitter of triode Q2 is connected with the binding post 1 of power supply J1, the base stage of triode Q2 is connected with the major loop between load J2 and power supply J1, be serially connected with sample resistance R2 between the emitter of triode Q2 and base stage.
Its operation principle is as follows:
In DC loop, when load current during less than the setup parameter value, because electric current is less, voltage is less than the required base voltage of Q2 triode conducting, not conducting of Q2, R3 and Q2 in the protection loop do not work, and whole loop current flows to and is: power supply+à load à R2 à power supply-,, be in normal operating conditions; When load current during greater than the setup parameter value; because electric current is larger; voltage is greater than the required base voltage of Q2 triode conducting; the Q2 conducting; R3 in the protection loop and Q2 work, make its whole current circuit be divided into two-way, and wherein the current circuit of major loop is: power supply+à load à R2 à power supply-; the current circuit of controlled shunting circuit is: power supply+à D1 à R3 à Q2 à power supply-and, circuit can recover automatically.
Embodiment four
as shown in Figure 5, current foldback circuit of the present utility model comprises power supply J1, load J2 and be attempted by power supply J1 and load J2 between controlled shunting circuit on major loop, this controlled shunting circuit comprises a shunt resistance R3 and is serially connected in respectively the flow-dividing control switch at shunt resistance R3 two ends, one component stream switch is by diode D1, triode Q1 and sample resistance R1 form, the anode of diode D1 is connected with the binding post 2 of power supply J1, the negative electrode of diode D1 is connected with the end of shunt resistance R3, an end that is connected with the negative electrode of diode D1 in triode Q1 collector electrode and shunt resistance R3 is connected, the base stage of triode Q1 is connected between power supply J1 and load J2 on major loop, the emitter of triode Q1 is connected with the anode of diode D1, sample resistance R1 is serially connected between the emitter and base stage of triode Q1, another component stream switch consists of diode D2, triode Q2 and sample resistance R2, the anode of diode D2 is connected with the binding post 1 of power supply J1, the negative electrode of diode D2 is connected with the end of shunt resistance R3, an end that is connected with the negative electrode of diode D2 in triode Q2 collector electrode and shunt resistance R3 is connected, the base stage of triode Q2 is connected between power supply J1 and load J2 on major loop, the emitter of triode Q2 is connected with the anode of diode D2, and sample resistance R2 is serially connected between the emitter and base stage of triode Q2.Current foldback circuit in the present embodiment is not only applicable to DC circuit, also is applicable to alternating current circuit, and its operation principle is as follows:
In DC loop, power supply terminal 2 is for just, and 1 for negative.
When load current during less than the setup parameter value; because electric current is less; R1, R2 both end voltage are less than Q1, the required base voltage of Q2 triode conducting; Q1, not conducting of Q2; D1, R3, Q2 in the protection loop do not work; whole loop current flows to: power supply+à R1 à load à R2 à power supply-and, be in normal operating conditions.
When load current during greater than the setup parameter value; because electric current is larger; R1, R2 both end voltage are greater than Q1, the required base voltage of Q2 triode conducting; Q1, Q2 conducting; D1, R3 in the protection loop, Q2 work; make its whole current circuit be divided into two-way, wherein a road current circuit is: power supply+à R1 à load à R2 à power supply-, an other shunt current loop, road is: power supply+à D1 à R3 à Q2 à power supply-.
In DC loop, power supply terminal 1 is being for just, and 2 when negative.
When load current during less than the setup parameter value; because electric current is less; R1, R2 both end voltage are less than Q1, the required base voltage of Q2 triode conducting; Q1, not conducting of Q2; D2, R3, Q1 in the protection loop do not work; whole loop current flows to: power supply+à R2 à load à R1 à power supply-and, be in normal operating conditions.
When load current during greater than the setup parameter value; because electric current is larger; R1, R2 both end voltage are greater than Q1, the required base voltage of Q2 triode conducting; Q1, Q2 conducting; D2, R3 in the protection loop, Q1 work; make its whole current circuit be divided into two-way, wherein a road current circuit is: power supply+à R2 à load à R1 à power supply-, an other shunt current loop, road is: power supply+à D2 à R3 à Q1 à power supply-.
In ac circuit, when power supply was in positive half cycle, namely power supply terminal 2 had been for just, and 1 when negative.Whole loop works situation is with in DC loop, and power supply terminal 2 is being for just, and 1 working condition when bearing is identical.
When load current during less than the setup parameter value; because electric current is less; R1, R2 both end voltage are less than Q1, the required base voltage of Q2 triode conducting; Q1, not conducting of Q2; D1, R3, Q2 in the protection loop do not work; whole loop current flows to: power supply+à R1 à load à R2 à power supply-and, be in normal operating conditions.
When load current during greater than the setup parameter value; because electric current is larger; R1, R2 both end voltage are greater than Q1, the required base voltage of Q2 triode conducting; Q1, Q2 conducting; D1, R3 in the protection loop, Q2 work; make its whole current circuit be divided into two-way, wherein a road current circuit is: power supply+à R1 à load à R2 à power supply-, an other shunt current loop, road is: power supply+à D1 à R3 à Q2 à power supply-.
In ac circuit, when power supply was in negative half period, namely power supply terminal 1 had been for just, and 2 when negative.Whole loop works situation is with in DC loop, and power supply terminal 1 is being for just, and 2 working conditions when bearing are identical.
When load current during less than the setup parameter value; because electric current is less; R1, R2 both end voltage are less than Q1, the required base voltage of Q2 triode conducting; Q1, not conducting of Q2; D2, R3, Q1 in the protection loop do not work; whole loop current flows to: power supply+à R2 à load à R1 à power supply-and, be in normal operating conditions.
When load current during greater than the setup parameter value; because electric current is larger; R1, R2 both end voltage are greater than Q1, the required base voltage of Q2 triode conducting; Q1, Q2 conducting; D2, R3 in the protection loop, Q1 work; make its whole current circuit be divided into two-way, wherein a road current circuit is: power supply+à R2 à load à R1 à power supply-, an other shunt current loop, road is: power supply+à D2 à R3 à Q1 à power supply-.
Claims (4)
1. current foldback circuit; it is characterized in that: this current foldback circuit comprise mains side terminals, load-side and be attempted by mains side and load-side between the controlled shunting circuit of major loop, this controlled shunting circuit comprises shunt resistance and at least at the flow-dividing control switch of shunt resistance one end serial connection.
2. current foldback circuit according to claim 1; it is characterized in that: described flow-dividing control switch is a NPN type triode; the collector and emitter of this triode is serially connected in described controlled shunting circuit; collector electrode is connected with an end of shunt resistance; emitter is connected with terminals of mains side, and the base stage of triode is connected with the major loop between mains side and load-side.
3. current foldback circuit according to claim 2, is characterized in that: be serially connected with sample resistance between the emitter of described triode and base stage.
4. current foldback circuit according to claim 3, it is characterized in that: described controlled shunting circuit also comprises a diode, and the negative electrode of diode is connected with an end of shunt resistance, and anode is connected with terminals of mains side.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2013202826318U CN203289091U (en) | 2013-05-22 | 2013-05-22 | Overcurrent protection circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2013202826318U CN203289091U (en) | 2013-05-22 | 2013-05-22 | Overcurrent protection circuit |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN203289091U true CN203289091U (en) | 2013-11-13 |
Family
ID=49545435
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN2013202826318U Expired - Lifetime CN203289091U (en) | 2013-05-22 | 2013-05-22 | Overcurrent protection circuit |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN203289091U (en) |
-
2013
- 2013-05-22 CN CN2013202826318U patent/CN203289091U/en not_active Expired - Lifetime
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| CX01 | Expiry of patent term |
Granted publication date: 20131113 |
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| CX01 | Expiry of patent term |