To provide a power supply circuit for an LED which can improve the power factor and reduce high harmonic current by using a simple method.
The power supply circuit 10 for an LED includes a rectifying circuit 16 and a drive circuit 22 for feeding an LED 14. The drive circuit 22 includes a switching element 26; a current detection resistance 32, of which one end is connected to a second terminal 26b of the switching element 26 and other end is connected to a zero volt line 20; and an integration circuit 34 for outputting an integration voltage Vc, in receiving a current detection voltage Vs generated at the current detection resistance 32, and a comparison circuit 42 of a PWM circuit 36 compares the integrated voltage Vc and a reference voltage Vref, and turns on the switching element 26, by outputting a reset signal to a flip-flop 38, when the integration voltage Vc reaches the reference voltage Vref.
| JPH07211463 | LIGHTING SYSTEM |
| JP2007080882 | LIGHT ADJUSTING DEVICE |
| JPH09318125 | RANGE HOOD |
SENBA KAZUAKI
MITO YASUYUKI
KAGA COMPONENT KK
Yuji Tada
Maki Ichikawa
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