CN2625949Y - Power supply overcurrent protection circuit formed by three-terminal voltage-stabilizing chip - Google Patents
Power supply overcurrent protection circuit formed by three-terminal voltage-stabilizing chip Download PDFInfo
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- CN2625949Y CN2625949Y CN03222654.3U CN03222654U CN2625949Y CN 2625949 Y CN2625949 Y CN 2625949Y CN 03222654 U CN03222654 U CN 03222654U CN 2625949 Y CN2625949 Y CN 2625949Y
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- 239000003990 capacitor Substances 0.000 abstract 2
- 239000004065 semiconductor Substances 0.000 abstract 2
- 230000001681 protective effect Effects 0.000 description 9
- 230000005855 radiation Effects 0.000 description 4
- 230000000694 effects Effects 0.000 description 3
- 230000000087 stabilizing effect Effects 0.000 description 3
- 230000015572 biosynthetic process Effects 0.000 description 2
- 238000006243 chemical reaction Methods 0.000 description 2
- 230000009467 reduction Effects 0.000 description 2
- 230000009471 action Effects 0.000 description 1
- 239000000853 adhesive Substances 0.000 description 1
- 230000001070 adhesive effect Effects 0.000 description 1
- 230000003321 amplification Effects 0.000 description 1
- 230000008901 benefit Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 230000005611 electricity Effects 0.000 description 1
- 230000006870 function Effects 0.000 description 1
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Abstract
The utility model discloses a can not only carry out general overcurrent protection, can protect the power under the power temperature rise's that causes again for a long time overflowing to send out the warning, in time prevent among chip and the circuit power overcurrent protection circuit that constitutes with three-terminal steady voltage chip that each component device damaged. It includes an alarm device, and it contains a relay, speaker, diode, its characterized in that includes: the working circuit comprises a stabilized voltage power supply consisting of a three-terminal stabilized voltage chip, two capacitors connected with the three-terminal stabilized voltage chip in parallel, a series resistor and an electronic switch connected with the three-terminal stabilized voltage chip in series; the protection circuit comprises a stabilized voltage power supply consisting of a three-terminal stabilized voltage chip, three parallel capacitors, two resistors and a potentiometer; the circuit for setting the overcurrent protection current value comprises an operational amplifier, a resistor and a semiconductor triode, wherein the resistor and the semiconductor triode are connected with the operational amplifier in series.
Description
Technical field
The utility model relates to a kind of power supply that constitutes with the three-terminal voltage-stabilizing chip, the overcurrent protection function with high reliability.The overcurrent that this circuit application is caused the maloperation of testing chip in the electronic experiment case causes testing the chip damage, has certain protective role.
Background technology
At present, the stabilized voltage supply of being made up of the three-terminal voltage-stabilizing chip is used in more place.Though the three-terminal voltage-stabilizing chip internal all has current foldback circuit, when overcurrent took place, along with the temperature rise of three-terminal voltage-stabilizing chip, when reaching a certain moment, the three-terminal voltage-stabilizing chip also can burn out, and caused power circuit to damage, and influenced entire equipment work.For example, in the electronic experiment case that institution of higher learning use.
Summary of the invention
The purpose of this utility model then is the problem that exists at above-mentioned prior art; designed and a kind ofly can not only carry out general overcurrent protection; under the situation of the power supply temperature rise that can cause power supply is protected again at long overcurrent; and send warning, in time prevent the power supply current foldback circuit that each components and parts damages in chip and the circuit with three-terminal voltage-stabilizing chip formation.
The purpose of this utility model can reach by following measure:
A kind of power supply current foldback circuit that constitutes with the three-terminal voltage-stabilizing chip, comprise a warning device, it comprises a relay, loudspeaker, diode, it is characterized in that comprising: an operating circuit, it comprises the stabilized voltage supply that three-terminal voltage-stabilizing chip is formed, and two electric capacity in parallel with the three-terminal voltage-stabilizing chip and resistance in series, reaches an electronic switch that is in series with the three-terminal voltage-stabilizing chip; A holding circuit, it comprises the stabilized voltage supply that three-terminal voltage-stabilizing chip is formed, three shunt capacitances and two resistance and a potentiometer; Set overcurrent protection current value circuit for one, it comprises an operational amplifier, reaches resistance and a transistor of being connected in series with operational amplifier.
The purpose of this utility model can also reach by following measure:
Wherein stabilized voltage supply can be made up of 78 types series or 79 types series three-terminal voltage-stabilizing chip in the operating circuit.
Wherein electronic switch is the normally closed switch K1 of relay J 1.
The resistance R 1 that wherein is connected in series in the operating circuit inserts the inverting input of operational amplifier.
Wherein in the holding circuit resistance R 2 with incorporate circuit into after potentiometer Rb connects, the resistance R 3 of connecting with resistance R 2 inserts the in-phase input end of operational amplifiers.
Wherein resistance R 4 is connected in series with the base stage of operational amplifier output terminal and triode T1.
Triode T1 wherein is NPN type BJT, and collector is connected with warning circuit, grounded emitter.
Wherein relay J 1 is controlled normally closed switch K1.
Advantage of the present utility model:
The power supply current foldback circuit that the utility model constitutes on the one hand, the too high chip that causes of the temperature that the long-time overcurrent protection of three-terminal voltage-stabilizing chip is caused damages, and good improvement is arranged; On the other hand, it is applied in the electronic experiment case, to the maloperation of experiment chip and the overcurrent that causes causes testing chip to damage, also has the certain protection effect.
Description of drawings
Fig. 1 is circuit theory diagrams of the present utility model;
Fig. 2 is the preferred embodiment corresponding to circuit theory shown in Figure 1;
Fig. 3 is the not curve maps of voltage and electric current during radiation fin of 7805 voltage stabilizing chips;
The curve map of voltage and electric current when Fig. 4 is 7805 voltage stabilizing chip radiation fins;
Fig. 5 is 7805 voltage stabilizing chips voltage and time relation curve maps when not having heat radiator.
Embodiment
The utility model is described in further detail below in conjunction with embodiment shown in the drawings:
Circuit structure of the present utility model comprises transformer, operating circuit, holding circuit, operational amplification circuit, alarm, electronic switch as shown in Figure 1.Fig. 2 is the preferred embodiments (is example with 7805 three-terminal voltage-stabilizing chips) of Fig. 1; for different chips; required protective current difference; as TTL chip and CMOS chip; at this moment; can be according to voltage shown in Figure 3 and current relationship, set the magnitude of voltage that protective current is determined this moment, adjust the reference voltage of three-terminal voltage-stabilizing chip in the holding circuit at regulator potentiometer Rb.Make in determining experiment behind the chip used maximum protection current value; adjust reference voltage, when overcurrent took place, voltage fell to reference voltage value when following; the amplifier conducting; through triode T1, utilize the control action of BJT, the energy conversion that power supply is given is stronger electric signal; become the sound that has amplified through loudspeaker reduction then; simultaneously, relay J 1 conducting, the magnet adhesive drives the normally closed switch K1 disconnecting circuit of itself behind its coil electricity.
When the three-terminal voltage-stabilizing chip in giving operating circuit added heat radiator, voltage and protective current value curve were as shown in Figure 4; When radiation fin not; voltage and protective current value curve are as shown in Figure 3; by Fig. 3 and Fig. 4 as can be seen; voltage regulation performance when the three-terminal voltage-stabilizing chip adds heat radiator than radiation fin not is good; at voltage under the different situations and protective current value curve, we can set different protective current values.Fig. 3 and Fig. 4 have also shown the temperature rise influence that voltage will cause in the time of also will being subjected to overcurrent and have reduced; as shown in Figure 5; voltage and time relation curve have been shown; increase the prolongation of time along with electric current; the chip internal temperature raises; the voltage reduction causes and accelerates to arrive the time of protective current value and cut off the power supply, and can not cause chip to burn out owing to temperature is too high.The influence (time t is directly proportional with temperature T, and time t and voltage V are inversely proportional to) that Fig. 5 utilizes voltage and time relation to show temperature voltage is caused.
Above-mentioned is to be the chip protection preferred embodiments of 1A at rated current, to rated current be 3A, 5A chip in like manner.
Principle of work of the present utility model is as follows:
With 7805 three-terminal voltage-stabilizing chips is that example setting operating voltage is 5 volts; during circuit working; 220 volts of voltage is through transformer and the bridge rectifier circuit output forward voltage greater than 6 volts; normally closed switch K1 through relay J 1; often make and break is closed K1 and is entered operating circuit; one the tunnel enters holding circuit, and through the bleeder circuit (holding circuit is by the protective current value of this bleeder circuit) that potentiometer Rb, resistance R 2, resistance R 3 are formed, is connected to the operational amplifier positive input.When chip works long hours when causing that temperature is too high; voltage on the resistance R 1 falls to its reference voltage value; the operational amplifier counter-rotating, triode T1 conducting, warning circuit conducting; the power Vcc Conversion of energy is an electric signal; be reduced to audible alarm through loudspeaker, relay J 1 conducting simultaneously, normally closed switch K1 opens; working line disconnects, thereby plays the effect of protection stable state power supply.In like manner, when the maloperation of experiment chip, the amplifier counter-rotating, the warning circuit conducting, circuit disconnects, and also plays the effect of protection power supply.
Claims (8)
1. power supply current foldback circuit that constitutes with the three-terminal voltage-stabilizing chip, comprise a warning device, it comprises a relay, loudspeaker, diode, it is characterized in that comprising: an operating circuit, it comprises the stabilized voltage supply that three-terminal voltage-stabilizing chip is formed, and two electric capacity in parallel with the three-terminal voltage-stabilizing chip and resistance in series, reaches an electronic switch that is in series with the three-terminal voltage-stabilizing chip; A holding circuit, it comprises the stabilized voltage supply that three-terminal voltage-stabilizing chip is formed, three shunt capacitances and two resistance and a potentiometer; Set overcurrent protection current value circuit for one, it comprises an operational amplifier, reaches resistance and a transistor of being connected in series with operational amplifier.
2. the power supply current foldback circuit that constitutes with the three-terminal voltage-stabilizing chip as claimed in claim 1 is characterized in that: its stabilized voltage supply is made up of 78 types series or 79 types series three-terminal voltage-stabilizing chip.
3. the power supply current foldback circuit that constitutes with the three-terminal voltage-stabilizing chip as claimed in claim 1, it is characterized in that: wherein electronic switch is the normally closed switch K1 of relay J 1.
4. the power supply current foldback circuit that constitutes with the three-terminal voltage-stabilizing chip as claimed in claim 1 is characterized in that: the R1 resistance of serial connection inserts the inverting input of operational amplifier.
5. the power supply current foldback circuit that constitutes with the three-terminal voltage-stabilizing chip as claimed in claim 1 is characterized in that: resistance R 2 with incorporate circuit into, the in-phase input end of the resistance R 3 access operational amplifiers of connecting after potentiometer Rb connects with resistance R 2.
6. the power supply current foldback circuit that constitutes with the three-terminal voltage-stabilizing chip as claimed in claim 1, it is characterized in that: wherein resistance R 4 is connected in series with the base stage of operational amplifier output terminal and triode T1.
7. the power supply current foldback circuit that constitutes with the three-terminal voltage-stabilizing chip as claimed in claim 1, it is characterized in that: triode T1 wherein is NPN type BJT, collector is connected with warning circuit, grounded emitter.
8. the power supply current foldback circuit that constitutes with the three-terminal voltage-stabilizing chip as claimed in claim 1 is characterized in that: relay J 1 control normally closed switch K1.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN03222654.3U CN2625949Y (en) | 2003-06-12 | 2003-06-12 | Power supply overcurrent protection circuit formed by three-terminal voltage-stabilizing chip |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN03222654.3U CN2625949Y (en) | 2003-06-12 | 2003-06-12 | Power supply overcurrent protection circuit formed by three-terminal voltage-stabilizing chip |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN2625949Y true CN2625949Y (en) | 2004-07-14 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN03222654.3U Expired - Fee Related CN2625949Y (en) | 2003-06-12 | 2003-06-12 | Power supply overcurrent protection circuit formed by three-terminal voltage-stabilizing chip |
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| Country | Link |
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| CN (1) | CN2625949Y (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101777760A (en) * | 2010-03-05 | 2010-07-14 | 厦门大学 | Laser power supply overcurrent protection circuit with locking function |
-
2003
- 2003-06-12 CN CN03222654.3U patent/CN2625949Y/en not_active Expired - Fee Related
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101777760A (en) * | 2010-03-05 | 2010-07-14 | 厦门大学 | Laser power supply overcurrent protection circuit with locking function |
| CN101777760B (en) * | 2010-03-05 | 2012-07-04 | 厦门大学 | Laser power supply overcurrent protection circuit with locking function |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| C19 | Lapse of patent right due to non-payment of the annual fee | ||
| CF01 | Termination of patent right due to non-payment of annual fee |