Power supply circuit

Abstract

This application discloses a power supply circuit suitable for electronic devices. This power supply circuit includes an input interface, a charging circuit, a switching circuit, and a protection circuit. The input interface receives a power supply voltage. The charging circuit converts the received power supply voltage into a system voltage and provides the system voltage to the system power supply terminal. The switching circuit is coupled between the input interface and the charging circuit and is controlled to turn on or off by a control signal. The protection circuit adjusts the control signal provided to the switching circuit according to the system voltage fed back from the system power supply terminal, thereby controlling the switching circuit.

Claims

1. A power supply circuit suitable for an electronic device, the power supply circuit comprising: An input interface, configured to receive a power supply voltage; A charging circuit configured to convert a received power supply voltage into a system voltage and provide the system voltage to a system power supply terminal; a switching circuit coupled between the input interface and the charging circuit, configured to be turned on or off by a control signal; a protection circuit coupled to the switching circuit and the system power supply terminal, configured to adjust the control signal provided to the switching circuit according to the system voltage fed back from the system power supply terminal, thereby controlling the switching circuit, the protection circuit comprising: a voltage detection circuit configured to detect the system voltage at the system power supply terminal and generate a first detection signal according to the system voltage; a control circuit coupled to the voltage detection circuit and configured to provide the control signal to the switching circuit according to the first detection signal; and a power supply voltage detection circuit coupled to the input interface and the protection circuit, configured to detect the power supply voltage and generate a power supply side detection signal according to the power supply voltage, wherein the control circuit receives the power supply side detection signal and adjusts the control signal according to the power supply side detection signal.

2. The power supply circuit as claimed in claim 1, wherein when the system voltage is greater than a voltage threshold, the voltage detection circuit generates a first detection signal at a first logic level, and the control circuit, in response to the first detection signal at the first logic level, converts the control signal from the first logic level to a second logic level to disconnect the switching circuit.

3. The power supply circuit as claimed in claim 1, wherein the voltage detection circuit comprises: A voltage divider circuit is configured to receive the system voltage and divide the system voltage to output a divided voltage. And a first comparator, whose non-inverting input receives the divided voltage, whose inverting input receives a first reference voltage, and whose output outputs the first detection signal.

4. The power supply circuit as claimed in claim 3, wherein the voltage divider circuit comprises: A first resistor, whose first terminal receives the system voltage and whose second terminal outputs the divided voltage; And a second resistor, the first end of which is coupled to the second end of the first resistor, and the second end of which is grounded.

5. The power supply circuit as claimed in claim 1, wherein the protection circuit further comprises: A temperature detection circuit configured to detect the temperature of a detection point within the electronic device and generate a second detection signal based on the temperature of the detection point; and an OR gate having a first input terminal receiving the first detection signal, a second input terminal receiving the second detection signal, and an output terminal outputting a third detection signal to the control circuit.

6. The power supply circuit as claimed in claim 5, wherein when the temperature at the detection point is greater than a temperature threshold, the temperature detection circuit generates the second detection signal at a first logic level, and the control circuit, in response to the third detection signal at the first logic level, converts the control signal from the first logic level to a second logic level to disconnect the switching circuit.

7. The power supply circuit as claimed in claim 5, wherein the temperature detection circuit comprises: A third resistor, whose first terminal receives a second reference voltage and whose second terminal outputs a temperature voltage; A thermistor, the first end of which is coupled to the second end of the third resistor and the second end of which is grounded; and a second comparator, the non-inverting input of which receives a third reference voltage, the inverting input of which receives the temperature voltage, and the output of which outputs the second detection signal.

8. The power supply circuit as claimed in claim 1, wherein the charging circuit comprises: A first charging element, the first end of which is coupled to an input terminal, wherein the input terminal is used to receive the power supply voltage; A second charging element, the first end of which is coupled to the second end of the first charging element and the second end is grounded; a third charging element, the first end of which is coupled to the power supply of the system; a fourth charging element, the first end of which is coupled to the second end of the third charging element and the second end is grounded; and a fifth charging element, the first end of which is coupled to the second end of the first charging element and the second end of which is coupled to the second end of the third charging element.

Images