TPS61500: Enable pin to fit the PWM and Enable signal of outside

KJ Liu

Part Number: TPS61500

Hi Sir,

My customer consider using TPS61500 to replace the existing design, but there is an issue, in existing back light driver, the PWM and Enable is separated but TPS61500 is integrated, the logic AND is suggested to customer to use( both PWN and Enable of outside signal is the input of AND and connected the out to EN of TPS61500). is there any issue if using this design or do you have better suggestion. thanks you very much!

over 7 years ago

0 Rodney Jones over 7 years ago

TI__Prodigy 600 points

This item has been assigned, It will be replied to shortly.

0 Caryss Li over 7 years ago

TI__Expert 4550 points

Hi KJ,
It is OK to use AND logic to combin EN and PWM signal, please make sure the signal follow the logic level of TPS61500. If the PWM is programmale, the enable and disable could be done by PWM signal. When you want to enable, just provide PWM signal, and if you want to disable, you could keep PWM low more than 10ms, the device will be done.
Hope this helps.

0 KJ Liu over 7 years ago in reply to Caryss Li

Intellectual 530 points

Hi Sir,

My customer new idea is through changing the VFB of TPS61500 to dimming and he has completed the test in TPS61500 EVB as following picture but I wonder to know does it have influence that induce the Feedback is unstable. thanks you very much !

0 KJ Liu over 7 years ago in reply to Caryss Li

Intellectual 530 points

Hello,

Does it have any comment on it ? thanks!

0 Caryss Li over 7 years ago in reply to KJ Liu

TI__Expert 4550 points

Hi KJ,
Sorry for late reply. It is a possible way to do analog diimming but the device is not designed in that way. Customer needs to verify this method over whold operation range including dimming performance, accuracy, stability etc. Here is a Application note talks about this application, it is for another device but you could use it as a reference.
www.ti.com/.../slva471.pdf

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TPS61500: Enable pin to fit the PWM and Enable signal of outside