Hi Florian,

Could you please tell me some more details of your application, like your LED string, output current, EE, etc?

BR, Jared

Hey Jared,

the number of LED strings doesn't matter. A total output current of at least 1A would be necessary

BR, Florian

Hey Jared,

the number of LED strings doesn't matter. A total output current of at least 1A would be necessary

BR, Florian

Hi Florian,

Our expert will reply to your questions later, thanks for your patience.

BR

Patrick

Hi Florian,

It seems that we don't have a device that can satisfy both VIN 30V and IOUT 1A needs. Maybe you can see if the two device TLC6A598 and LM3435 can meet your requirement.

BR, Jared

I think you have several devices in stock that satisfy these requirements like the: TPS92515

I was just asking if you could recommend me one (maybe it is the TPS 92515) with the lowest possible output ripple current

BR;
Florian

Hi Florian,

I noticed that you mentioned at first is that "I am in search of a LED driver with a constant current output with no ripple!!!". Therefore, my understanding is the device without switching circuit, and it seems that there is no device which can satisfy both 30V input voltage and at lease 1A output current.

Now, you said you want to search "one(maybe it is the TPS92515) with the lowest possible output ripple current". Can I understand that you want to search a switching device? If this, my colleague Steven will recommend a better choice to you.

BR, Jared

You got it exactly right. I was searching for a device with no internal switch at first, and after longer research conducted that a high enough switching frequency paired with an LC should be enough: Maybe i should have communicated that ;).

(If you know any devices from other Brands that have no internal switch let me know. So far i only found the Analog Devices ADP8140.

Hi Florian,

Could you please tell us your application background?

Based on your requirement, I recommend TPS92630-Q1 to you.

BR, Jared

Hi Florian,

It looks like ADP8140 can only give you a 500mA max output per channel and Vin within 30V.

LM3464 is also a possible solution here, if it can meet your requirements. But maybe it will be a little bit over-spec for you.

BR,

Steven

So first of all thank you both for both for investing your time into this issue (other companies don't offer nearly as much support)

1. The ADP8140 offers 500mA per channel but 2A total. However it has other issues like a too long startup time which make it unuseable.
2. I'm currently testing a few devices and I am thinking that maybe for the benefit of having a non switching output I can scrap the 1A output requirement. I just need as much as possible so if you have suggestions there I'll be happy for them.
3. The driver is for stimulating live cells with a controllable Light source. Thats why the low ripple is so crucial. The human eye might not detect it but the cells respond rather sensitive to changes in their stimulation.
4. I looked at the LM3464. It is indeed a bit over-spec (I don't need a thermal control). Looking at the datasheet however it seems like this one has no internal switch and therefore a constant output??

Thank you all again. Looking forward to your answers

BR,
Florian

Hi Florian,

LM3464 is a linear (non-switching) LED driver, with external MOSFET, which gives you the capability of output larger current per channel.

BR,

Steven

I see. But does that mean there will be actually a DC signal at the output? Or will he just forward a modified Version of the PWM input?

Hi Florian,

The output of LM3464 just reflects the input PWM signal. (The output is a PWM / on-off current.)

If you need to adjust the amplitude of the current, then you can consider LM3463. Again, I guess this may be a little bit over-spec for you.

I want to check with you if a linear LED driver is a must? If not, I would recommend TPS922053, which contains a lot of dimming features that may fit your application.

BR,

Steven

Indeed the TPS922053 doesn't seem like a bad candidate. Especially because it apparently can use a PWM digital input signal and transform it to a analog output. Thats exactly what i have been looking for the entire time but due to my limited knowledge on LED Drivers I had a hard time descirbing it.

With that knowledge I also had a look at the TPS92200D2 which is simpler but supports the same main digital-> analog feature.

However it says in the datasheet that the dimming range is between 1%-100%.
How is this range in the TPS922053 when in analog output mode and do you know comparable devices to the TPS92200D2 with a larger dimming range.

All the best,
Florian

Hi Florian,

Steven is out of office and will reply to your questions once coming back, thanks for your patience.

BR

Patrick

Hi Florian,

TPS922053 can achieve analog dimming range from 0% to 100% in 256 steps. Each step will give you an around 100% / 256 = 0.39% increment in output current.

BR,

Steven

Hi Marek,

Do you have the same question as Florian? Is there anything I can help with?

BR,

Steven