PWM Control Dimming Halogen Lamp Circuit

Published:2011/4/27 18:39:00 Author:Christina | Keyword: PWM Control, Dimming Halogen Lamp | From:SeekIC

The PWM control dimming halogen lamp circuit is as shown. Rated voltage of the halogen lamp is 12V, the nominal power is 20W, the dimmer circuit can adjust the intensity of halogen lamp from zero to maximum. Lighting halogen lamp always transforms the frequency electricity (220V or 110V) into 12V AC voltage by using the power transformer. In order to provide operating voltage to the pwm controller sg3524 (ic1) and the op amp lm324 (ic2), the DC voltage will apply to the ic1's 15-pin and 4-pin of ic2. Between the rectifier filter circuit and the halogen lamp, we need to connect the pnp compound transistor vt1 and the vt1 is controlled by the pwm signal of ic1. Through the collector output transistor of vt1, we connect the l1 and c2 to form the lc filter, so we can get the 12V DC voltage to supply power. As the lamp current is 1.67a (20 w/12 v), r4 is 0.1v, the output voltage (5V) sent by ic2's 1-pin will be back to the ic1's 1-pin.



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