Patent ID: 9661710
Date: 2017-05-23
CPC Classifications: H05B

Claim:
1. A dimmer holding current control circuit for phase cut dimming power supply, comprises a phase cut dimming power supply circuit and a LED lamp and a dimmer holding current control circuit; the phase cut dimming power supply circuit and the LED lamp is composed of an anti-interference circuit, a bridge rectifier, a main circuit of phase cut dimming power supply and LED lamp, which are connected in turn; the anti-interference circuit is connected to L terminal and N terminal of main supply through a fuse; wherein the dimmer holding current control circuit is composed of a rectifier diode I, a rectifier diode II, a field-effect transistor, a triode, a current-limiting resistance I, a current-limiting resistance II, a sampling resistance I, a sampling resistance II, a diode, a capacitance and resistance; the anodes of the rectifier diode I and the rectifier diode II are respectively connected to L terminal and N terminal of main supply input of the phase cut dimming power supply; the cathode of the rectifier diode I and the cathode of the rectifier diode II are connected to each other and to one end of the current-limiting resistance I, one end of the sampling resistance I and one end of the resistance; the other end of the current-limiting resistance I is connected to the drain electrode of the field-effect transistor; the other end of the resistance is connected to the grid electrode of the field-effect transistor and the collector of the triode; the other end of the sampling resistance I is connected to the base of the triode, the cathode of the diode, one end of the capacitance and one end of the sampling resistance II; the source electrode of the field-effect transistor is connected to the anode of the diode, the other end of the capacitance and one end of the current-limiting resistance II; the other end of the sampling resistance II, the other end of the current-limiting resistance II and the emitter of the triode are connected to the circuit common ground.