The invention belongs to the technical field of illumination power supplies, and specifically relates to a closed-
loop control LED power supply, wherein an
alternating current commercial power input of 110V-230V is connected with a filtering coil L wiring terminal of a filtering coil L; a wiring terminal is connected with a commercial power N stage; a
voltage-regulating variable
resistor R3 is connected with a bidirectional
diode DB3 after being connected in series with a
resistor R2, a triggering
capacitor C2 and a
thermistor RT, so as to constitute a
silicon-controlled conduction angle
control circuit. The bidirectional
diode DB3 is connected with a G stage of a
silicon controlled
rectifier. The
thermistor RT is put in a proper position of an
LED lamp for controlling a
silicon-controlled conduction angle, thereby providing a closed-
loop control signal for the
LED lamp. A current-limiting
resistor R1 is connected with all load terminals of the
LED lamp; other terminals of the LED lamp are connected with a full-bridge
cathode. A full-bridge output terminal is connected with the LED lamp. A full-bridge input terminal is connected with the commercial power through the silicon-controlled
rectifier. The
full bridge works in both the positive cycle and the
negative cycle of the
alternating current. A filtering
capacitor C1 is connected with a rectifying
full bridge. The closed-
loop control LED power supply has the advantages of a
simple circuit, a safe and reliable use, a low cost, and a low
fault rate.