Adjustable overcurrent protection circuit

Abstract

This invention discloses an adjustable overcurrent protection circuit coupled to a power supply device. The adjustable overcurrent protection circuit includes an overcurrent protection circuit, a voltage detection circuit, and a compensation circuit. The overcurrent protection circuit is coupled to the power supply. The voltage detection circuit is coupled to the power supply and configured to detect the output voltage of the power supply. The compensation circuit is coupled to both the voltage detection circuit and the overcurrent protection circuit. When the output voltage exceeds a voltage threshold, the compensation circuit reduces the overcurrent protection value of the overcurrent protection circuit. When the output voltage does not exceed the voltage threshold, the overcurrent protection value remains unchanged.

Claims

1. An adjustable overcurrent protection circuit coupled to a power supply, the adjustable overcurrent protection circuit comprising: an overcurrent protection circuit coupled to the power supply; a voltage detection circuit coupled to a secondary side of the power supply and configured to detect an output voltage of the power supply; and a compensation circuit coupled to the voltage detection circuit and the overcurrent protection circuit; wherein when the output voltage is greater than a voltage threshold, the compensation circuit reduces an overcurrent protection value of the overcurrent protection circuit; and when the output voltage is not greater than the voltage threshold, the overcurrent protection value of the overcurrent protection circuit remains unchanged.

2. The adjustable overcurrent protection circuit as described in claim 1, wherein, The adjustable overcurrent protection circuit further includes a current detection circuit coupled to the power supply and the overcurrent protection circuit, and the current detection circuit is configured to detect an output current of the power supply.

3. The adjustable overcurrent protection circuit as described in claim 1, wherein, The voltage detection circuit includes a first resistor, a second resistor, and a comparator. A positive power supply terminal of the comparator receives the output voltage. A first terminal of the first resistor receives the output voltage. A second terminal of the first resistor is coupled to an inverting input terminal of the comparator. A non-inverting input terminal of the comparator receives a reference voltage. A first terminal of the second resistor is coupled to the inverting input terminal of the comparator. A second terminal of the second resistor and a negative power supply terminal of the comparator are grounded. An output terminal of the comparator is coupled to the compensation circuit.

4. The adjustable overcurrent protection circuit as described in claim 3, wherein, The compensation circuit includes a first transistor, a third resistor, and a fourth resistor. A first terminal of the third resistor receives the output voltage, a second terminal of the third resistor is coupled to a first terminal of the transistor, a first terminal of the first transistor is coupled to the output terminal of the comparator, a second terminal of the first transistor receives the output voltage, a third terminal of the first transistor is coupled to a first terminal of the fourth resistor, and a second terminal of the fourth resistor is coupled to the overcurrent protection circuit.

5. The adjustable overcurrent protection circuit as described in claim 4, wherein, The first transistor is a bipolar junction transistor, with the first end of the first transistor being a base, the second end of the first transistor being an emitter, and the third end of the first transistor being a collector.

6. The adjustable overcurrent protection circuit as described in claim 1, wherein, The voltage detection circuit includes a first resistor, a second resistor, and a comparator. A first terminal of the first resistor receives the output voltage, a positive power supply terminal of the comparator receives the output voltage, a second terminal of the first resistor is coupled to a non-inverting input terminal of the comparator, a first terminal of the second resistor is coupled to the non-inverting input terminal, a second terminal of the second resistor and a negative power supply terminal of the comparator are grounded, an inverting input terminal of the comparator receives a reference voltage, and an output terminal of the comparator is coupled to the compensation circuit.

7. The adjustable overcurrent protection circuit as described in claim 6, wherein, The compensation circuit includes a unidirectional conducting element and a third resistor. A first end of the unidirectional conducting element is coupled to the output terminal of the comparator, a second end of the unidirectional conducting element is coupled to a first end of the third resistor, and a second end of the third resistor is coupled to the overcurrent protection circuit.

8. The adjustable overcurrent protection circuit as described in claim 7, wherein, The unidirectional conducting element is a diode, with the first end of the unidirectional conducting element being an anode and the second end of the unidirectional conducting element being a cathode.

9. The adjustable overcurrent protection circuit as described in claim 1, wherein, The voltage detection circuit includes a first resistor, a second resistor, and a comparator. A first terminal of the first resistor receives the output voltage, a positive power supply terminal of the comparator receives the output voltage, a second terminal of the first resistor is coupled to an inverting input terminal of the comparator, a non-inverting input terminal of the comparator receives a reference voltage, a first terminal of the second resistor is coupled to the inverting input terminal, and an output terminal of the comparator is coupled to the compensation circuit.

10. The adjustable overcurrent protection circuit as described in claim 9, wherein, The compensation circuit includes a unidirectional conducting element, a third resistor, a first transistor, and a fourth resistor. A first terminal of the third resistor receives the output voltage, a second terminal of the third resistor is coupled to a first terminal of the unidirectional conducting element, a second terminal of the unidirectional conducting element is coupled to the output terminal of the comparator, a first terminal of the first transistor is coupled to a second terminal of the third resistor, a second terminal of the first transistor receives the output voltage, a third terminal of the first transistor is coupled to a first terminal of the fourth resistor, and a second terminal of the fourth resistor is coupled to the overcurrent protection circuit.

11. The adjustable overcurrent protection circuit as described in claim 10, wherein, The unidirectional conducting element is a diode, with the first end of the unidirectional conducting element being an anode and the second end of the unidirectional conducting element being a cathode.

12. The adjustable overcurrent protection circuit as described in claim 10, wherein, The first transistor is a bipolar junction transistor, with the first end of the first transistor being a base, the second end of the first transistor being an emitter, and the third end of the first transistor being a collector.

13. The adjustable overcurrent protection circuit as described in claim 1, wherein, The voltage detection circuit includes a first resistor, a second resistor, and a comparator. A first terminal of the first resistor receives the output voltage, a positive power supply terminal of the comparator receives the output voltage, a second terminal of the first resistor is coupled to a non-inverting input terminal of the comparator, a first terminal of the second resistor is coupled to the non-inverting input terminal, a second terminal of the second resistor is grounded to a negative power supply terminal of the comparator, an inverting input terminal of the comparator receives a reference voltage, and an output terminal of the comparator is coupled to the compensation circuit.

14. The adjustable overcurrent protection circuit as described in claim 13, wherein, The compensation circuit includes a third resistor and a current mirror circuit. A first end of the third resistor is coupled to the output terminal of the comparator, a second end of the third resistor is coupled to one end of the current mirror circuit, and the other end of the current mirror circuit is coupled to the overcurrent protection circuit.

15. The adjustable overcurrent protection circuit as described in claim 14, wherein, The current mirror circuit includes a first transistor and a second transistor. A first terminal of the first transistor is coupled to a first terminal of the second transistor. A second terminal of the first transistor and a second terminal of the second transistor are grounded. A third terminal of the first transistor is coupled to a second terminal of the third resistor. A third terminal of the second transistor is coupled to the overcurrent protection circuit.

16. The adjustable overcurrent protection circuit as described in claim 15, wherein, The first transistor and the second transistor are two bipolar junction transistors. The first end of the first transistor is a base, the second end of the first transistor is an emitter, and the third end of the first transistor is a collector. The first end of the second transistor is a base, the second end of the second transistor is an emitter, and the third end of the second transistor is a collector.

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