nsubra2001
Newbie level 4
I designed a simple boost converter - 555 timer with 437kHz controlling the gate of the Mosfet, a 100muH inductor and 2.2muF capacitor. The duty cycle is 90%. The circuit converts 12v input to 90v output as desired. When I connect a 12w LED light to 120 volt ac, at the LED input (after the simple bridge rectifier and a few resistors to burn off some voltage), the voltage is 103.4v and the current is 123.8mA. When this LED light is connected to the boost converter (the rectifier and resistors were removed, only the bunch of LEDs connected), the LEDs light up but the current to the LED shows only 6mA, not 123mA. I thought may be the capacitor value was low. So I connected the boost converter to a regular filament bulb. I expected to see 6mA consumption but the bulb was drawing about 80mA (though it did not light up). Why is the current to the LED so low? I increased the capacitor to 4.4muF. Still the current drawn was only 6mA. The inductor is reated for 1.5A. Please help.