Patent ID: 9380678
Filing Date: 2016-06-28
CPC Classification: H02M,H05B

Claim Text:
1. An auxiliary power supply circuit of a two-wire dimmer, comprising: an auxiliary source capacitor and a disconnecting switch connected in series to form a series branch; a chopper switch connected in parallel with the series branch; and a control device connected to the chopper switch and the disconnecting switch, wherein the control device is configured to detect an auxiliary source voltage and receive a chopper voltage control signal, and output a signal to control the chopper switch and the disconnecting switch to be on or off according to a comparison result of the auxiliary source voltage with a preset voltage and a state of the chopper voltage control signal, to control charging of the auxiliary source capacitor; wherein the control device comprises a judging circuit and a disconnecting switch driving circuit, the judging circuit is configured to: the disconnecting switch driving circuit is configured to control the disconnecting switch to be on in a case that the chopper switch is off and the chopper voltage control signal is not turning off the chopper switch; or, wherein the control device comprises a judging circuit, a logic circuit and a disconnecting switch driving circuit, the judging circuit is configured to detect the auxiliary source voltage, compare the auxiliary source voltage with the preset voltage, output a first signal to the logic circuit in a case that the auxiliary source voltage is lower than a set lower limit value, and output a second signal to the logic circuit in a case that the auxiliary source voltage is higher than a set upper limit value; the logic circuit is configured to: receive the chopper voltage control signal and control the disconnecting switch and the chopper switch to be off in a case that the chopper voltage control signal is turning off the chopper switch; receive an output signal of the judging circuit, control the chopper switch to be off in a case that the output signal of the judging circuit is the first signal, control the disconnecting switch to be off in a case that the output signal of the judging circuit is the second signal, and control the chopper switch to be on in a case that the output signal of the judging circuit is the second signal and the chopper voltage control signal is not turning off the chopper switch; and the disconnecting switch driving circuit is configured to control the disconnecting switch to be on in a case that the chopper switch is off, the chopper voltage control signal is not turning off the chopper switch, and the output signal of the judging circuit is the first signal.