Hey everyone,

for a project which involves stimulation of live cells I am searching a LED Driver with PWM or digital dimming
All other specs aside can you guys give me a Driver that offers a scaled analog output.
A lot of Drivers i found just forward their input PWM signal to the output or create their own PWM signal, which is not sufficient for my application.
I need a CONSTANT current at the output. The ADP8140 provides this but has other problems that make him unusable for me.

Thanks in advance!
Best regards
Jordi

 

The ADP8140 provides this but has other problems that make him unusable for me.

Why is that?

 

Why is that?

The delay between EN-high and activation of Sink current is too long (about 8ms).

 

The delay between EN-high and activation of Sink current is too long (about 8ms).

Can you leave the EN high continuously and switch power to the LEDs?

 

Can you leave the EN high continuously and switch power to the LEDs?

I appreciate you trying to solve my problems (there are others besides the EN delay) with the ADP8140. Rest assured that I have thought about and tried several things to solve this. Some of them worked but where suboptimal.

But before explain my whole application to everyone I thought it would be easier to get one or maybe a few Drivers with the most important feature (constant analog output) and then decide on the best one based on my application.

So if you have a suggestion for an alternative that is great! If you don't it's ok ofc but I wont go on about how to "fix" my current setup cause it will waste a lot of time for both of us.

 

But before explain my whole application to everyone I thought it would be easier to get one or maybe a few Drivers with the most important feature (constant analog output) and then decide on the best one based on my application.

Can't really suggest any drivers without knowing the exact application.

 

If it has PWM or digital dimming, then the output current is not constant.

 

I appreciate you trying to solve my problems (there are others besides the EN delay) with the ADP8140. Rest assured that I have thought about and tried several things to solve this. Some of them worked but where suboptimal.

But before explain my whole application to everyone I thought it would be easier to get one or maybe a few Drivers with the most important feature (constant analog output) and then decide on the best one based on my application.

So if you have a suggestion for an alternative that is great! If you don't it's ok ofc but I wont go on about how to "fix" my current setup cause it will waste a lot of time for both of us.

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You didn't specify any parameters of the application (input and output voltage, output current, etc), so I'll provide some example with some parameters: you could check PAM2841
Don't be quick to dismiss it right away because there is "PWM" in description. It supports PWM and Analog dimming.
Analog dimming essentially adjusts output DC voltage to set the required DC current (you feed a bias DC voltage into feedback input).
It is a boost DC-DC converter, so there is switching (and PWM there as well), but it is filtered out by inductor and output capacitor. You may need to specify what ripple is acceptable and maybe adjust filter values beyond minimum recommended in example circuits.

 

Thanks everyone for your time! It helped me a bit in my research!
With the knowledge I achieved I formulated a new (hopefully) clearer question, but posted it in a new thread to keep things sorted.

All the best,
Jordi