| 摘要 |
A flyback-based power conversion apparatus and a power conversion method thereof are provided. By switching first and second detection switches disposed in a control chip and coupled to a multi-function pin of the control chip at different timings, the present invention applies a collocation of a voltage-current detection auxiliary circuit and a current detection circuit at a certain timing to execute a detection of the AC input voltage received by a flyback power conversion circuit, and the present invention applies a collocation of the auxiliary voltage-current detection circuit, an over temperature protection unit and an over voltage protection unit at another timing to execute detections of an over temperature protection and an over voltage protection. As the result, a single multi-function detection pin of the control pin is corresponding to a plurality of related function detections, so as to reduce the production cost of manufacturing the control chip. |
| 主权项 |
1. A power conversion apparatus, comprising:
a flyback power conversion circuit, configured to receive an alternating current (AC) input voltage, and convert the AC input voltage in response to a pulse width modulation (PWM) signal, so as to generate and provide a direct current (DC) output voltage, wherein the flyback power conversion circuit comprises:
a transformer, comprising a primary winding, a secondary winding and an auxiliary winding, wherein a common polarity terminal of the primary winding of the transformer is configured to receive the AC input voltage, a common polarity terminal of the secondary winding of the transformer is coupled to a safety ground, and a common polarity terminal of the auxiliary winding of the transformer is coupled to a dangerous ground;a power switch, wherein a first terminal of the power switch is coupled to an opposite polarity terminal of the primary winding, and a control terminal of the power switch is configured to receive the PWM signal;a first resistor, wherein a first terminal of the first resistor is coupled to a second terminal of the power switch, and a second terminal of the first resistor is coupled to the dangerous ground;a first diode, wherein an anode of the first diode is coupled to an opposite polarity terminal of the secondary winding, and a cathode of the first diode is configured to generate the DC output voltage;a capacitor, wherein a first terminal of the capacitor is coupled to the cathode of the first diode, and a second terminal of the capacitor is coupled to the safety ground; anda second diode, wherein an anode of the second diode is coupled to an opposite polarity terminal of the auxiliary winding; a control chip, coupled to the flyback power conversion circuit, and configured to generate the PWM signal in response to a power supply requirement so as to control an operation of the flyback power conversion circuit, wherein the first terminal of the first resistor provides an over current protection detection voltage to the control chip, and a cathode of the second diode is configured to generate a DC system voltage for the control chip; and a voltage-current detection auxiliary circuit, coupled between the flyback power conversion circuit and a multi-function detection pin of the control chip, configured to assist the control chip in executing a detection of the AC input voltage through the multi-function detection pin in a first detection phase, and configured to assist the control chip in executing detections of an over temperature protection and an over voltage protection through the multi-function pin in a second detection phase, wherein the voltage-current detection auxiliary circuit comprises:
a third diode, wherein a cathode of the third diode is coupled to the opposite polarity terminal of the auxiliary winding;a second resistor, wherein a first terminal of the second resistor is coupled to an anode of the third diode, and a second terminal of the second resistor is coupled to the multi-function detection pin;a thermistor, wherein a first terminal of the thermistor is coupled to the multi-function detection pin;a third resistor, wherein a first terminal of the third resistor is coupled to a second terminal of the thermistor, and a second terminal of the third resistor is coupled to the dangerous ground;a fourth diode, wherein an anode of the fourth diode is coupled to the opposite polarity terminal of the auxiliary winding; anda fourth resistor, wherein a first terminal of the fourth resistor is coupled to a cathode of the fourth diode, and a second terminal of the fourth resistor is coupled to the multi-function detection pin. |
