TPS61194: TPS61194

Ulli Braunsteffer

Part Number: TPS61194

Hi,

i had build my own evalboard for the first steps with the TPS61194.

I integratet 4 lines with 12 Leds (VR=2,8V@10mA).

First: one line with Uout=35V/Iset=10mA (1 Output) ==> the Leds shined bright for round about 30 sec., then they go out (no failure-led)

Second: two lines with Uout=35V/Iset=20mA (1 Output) ==> the Leds shined bright for round about 30 sec., then they go out and at once when I enable the driver the failure led is going on...

I changed the output (from 1 to 4) same procedure .... same result!!??

What can be the reasons?

Thanks in advance.

Ulli

over 6 years ago

0 Sean Zhou over 6 years ago

TI__Mastermind 22745 points

Hi Ulli,

Please upload your schematic and show your supply voltage. And Please give our the detail connection for each condition. Thanks.

Regards

Sean

0 Ulli Braunsteffer over 6 years ago in reply to Sean Zhou

Prodigy 80 points

Hi Sean,

you see downside my schematic - the violet circles are the connections I had choosen. My supply voltage is 12V.

So I had the test repeated with two lines by 12mA - some result as I describe above at my first question.

Thanks and best regards,

Ulli

0 Sean Zhou over 6 years ago in reply to Ulli Braunsteffer

TI__Mastermind 22745 points

Hi Ulli,

When you test with one or two LED sting, how do you deal with the unused channel? Have you connected the unused out channels to GND? And how about the output voltage setting when you do the test?

Regards

Sean

0 Ulli Braunsteffer over 6 years ago in reply to Sean Zhou

Prodigy 80 points

Hi Sean,

yes, I connected the unused outputs to GND.

And the output voltage (boost) is set for 45V - real about 37V.

Regards,

Ulli

0 Sean Zhou over 6 years ago in reply to Ulli Braunsteffer

TI__Mastermind 22745 points

Hi Ulli,

Another suggestion is that you can short some LEDs on your string and do the test again, whether the shining phenomenon is still here or not.

Regards

Sean

0 Ulli Braunsteffer over 6 years ago in reply to Sean Zhou

Prodigy 80 points

Hi Sean,

I tested your suggestion - but there is no difference behaviour!

It is the same ....

Regards,

Ulli

0 Sean Zhou over 6 years ago in reply to Ulli Braunsteffer

TI__Mastermind 22745 points

Hi Ulli,

Ok, I only have two suggestion: 1. could you provide some waveform for that phenomenon(Vout, Vsw, and current through inductor). 2. Request an TPS61194 EVM and test with our EVM.

Since I don't see the hardware and waveform, it is a little difficult for me to help to debug.

Regards

Sean

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TPS61194: TPS61194