LED driver with minimum duty cycle of 0

Thread Starter

avi9526

Joined Sep 16, 2022
1
hello


I have a practical task to make a simple LED lamp. I was using LDD-1000 for that purpose. But it does have minimal duty cycle of 20% (output is filtered so it's 20% of max. current) . Was looking for an alternative that could provide smooth control of current from 0A to 1A. Kinda lost in browsing web (product selection filters on digikey and ti does not have a "minimal duty cycle" option for some reason). Thinking about making PWM from some basic ICs like TL494 (or TL598). Could someone give me a bootstrap on this? Should I try to make it with 494 or there is newer options? Or maybe there is a widely used module similar to LDD-1000?


Thnx
 

Boggart

Joined Jan 31, 2022
54
Datasheet for the LDD1000 shows that in analogue dimming mode it goes to zero below 0.3V on the dimming input. The datasheet also shows a linear relationship from 0 to 100% of output for PWM dimming, I can't see anything in the datasheet about a minimum 20% limit.
 

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Boggart

Joined Jan 31, 2022
54
The LDD range of drivers are constant current drivers, clearly the OP needs that type of driver, he is probably driving one or more power LEDs from a voltage source. A simple PWM/MOSFET combo isn't going to do it without current sensing etc.
 
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