US 12,313,671 B2
Fault detection circuit, method and power adapter
Renjian Xie, Shenzhen (CN); and Yingyang Ou, Shenzhen (CN)
Assigned to Hynetek Semiconductor Co., Ltd., Shenzhen (CN)
Filed by Hynetek Semiconductor Co., Ltd., Shenzhen (CN)
Filed on Sep. 13, 2023, as Appl. No. 18/367,608.
Application 18/367,608 is a continuation of application No. PCT/CN2021/106560, filed on Jul. 15, 2021.
Claims priority of application No. 202110277716.6 (CN), filed on Mar. 15, 2021.
Prior Publication US 2023/0417823 A1, Dec. 28, 2023
Int. Cl. H01H 31/02 (2006.01); G01R 31/28 (2006.01)
CPC G01R 31/2843 (2013.01) 18 Claims
OG exemplary drawing
 
1. A fault detection circuit, comprising:
a first comparison unit, a second comparison unit, an impedance unit and a digital control unit;
the first comparison unit being connected with a sampling resistor and the digital control unit respectively, and being configured to output a first judgment signal to the digital control unit based on the voltage across the sampling resistor;
the second comparison unit being connected with the digital control unit and the impedance unit respectively, and the impedance unit being connected in series with the sampling resistor, the second comparison unit being configured to output a second judgment signal to the digital control unit based on the voltage across the impedance unit, or the second comparison unit being respectively connected with the digital control unit and a circuit in which the sampling resistor is connected in series with the impedance unit, and the second comparison unit being configured to output a second judgment signal to the digital control unit based on the voltage across the circuit in which the sampling resistor is connected in series with the impedance unit;
the digital control unit being configured to determine the working state of the sampling resistor based on the first judgment signal and the second judgment signal;
the fault detection circuit is applied to a USB-PD power adapter system, wherein the USB-PD power adapter system comprises a sampling resistor, a first amplifier, a transformer, a first switch tube and a USB interface, a first end of the sampling resistor is connected with a non-inverting input end of the first amplifier and a second end of the secondary side of the transformer, a second end of the sampling resistor is connected with an inverting input end of the first amplifier and the ground of the USB interface, a first end of the first switch tube is connected with a power pin of the USB interface, and a second end of the first switch tube is connected with a first end of the secondary side of the transformer, wherein the fault detection circuit comprises:
the first comparison unit comprising a first comparator;
a non-inverting input end of the first comparator is connected with an output end of the first amplifier, an inverting input end of the first comparator is connected with a first reference voltage, and an output end of the first comparator is connected with the digital control unit.