Constant Current Power Supply Using Pulse Width Modulation

ronsimpson

Joined Oct 7, 2019
680
Almost right. You put a resistor at the bottom of the LED and amplify and feed back to the 555.
The 2N7000 should get power from the +15V not the +12V.
The Gate drive from NE555 to 2N7000 is not good. You need a P-MOSFET or a new way of driving the Gate above the supply.
Do not need the 5.1V Zener.
There are "LED drivers" that are "buck mode" and "constant current" which would replace the second NE555 + LM311 + 2N7000 + more.
 

Thread Starter

Sergen Erbay

Joined Dec 19, 2019
23
Almost right. You put a resistor at the bottom of the LED and amplify and feed back to the 555.
The 2N7000 should get power from the +15V not the +12V.
The Gate drive from NE555 to 2N7000 is not good. You need a P-MOSFET or a new way of driving the Gate above the supply.
Do not need the 5.1V Zener.
There are "LED drivers" that are "buck mode" and "constant current" which would replace the second NE555 + LM311 + 2N7000 + more.
The 2N7000 taking power from the + 5V.
I want to set this circuit according to output 1A. Are there any Mosfet models you can recommend for this? and when I install this circuit, should I change the coil and capacitor value?
 
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