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

 

You might find a single chip solution, but while waiting, I will mention a PWM circuit that was brought to my attention a few years ago that can give you 0% pulse width to 100%.

IC1 is an NE555, IC2 is a comparitor like the LM393. The rest of the components are discussed at the link below.
https://www.rmcybernetics.com/science/diy-devices/diy-power-pulse-controller

 

Pwm dimmer on ebay will find cheap modules with 555, MOSFET, and pot.

 

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.

 

Use LM556 Dual Timer or two LM555.
First timer is in astable mode and second time in monostable mode.

 

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.