TPS61185: ISET switching issue

Patrick Chen

Part Number: TPS61185

Hello

Customer use below schematics to do ISET switching testing. But if switching rate is too fast, it will cause partial backlight LED not light up.

Could we know what is the issue root cause? Has any timing relationship between ISET switching and PWM ? Thank you.

Patrick

over 5 years ago

0 Sean Zhou over 5 years ago

TI__Mastermind 22745 points

Hi Patrick,

Do you mean you change the full scall current during dimming? You can use this circuit to change the full schall current, but you need to make sure that you can't change the full scall current during PM dimming and you need to reset device before dimming.

Regards

Sean

0 Patrick Chen over 5 years ago in reply to Sean Zhou

Mastermind 8875 points

Hello

Customer reset the IC and resend PWM signal. But it still can reproduce some LED channel not light up. Does any timing requinment on reset or power sequence? Thank you.

Patrick

0 Sean Zhou over 5 years ago in reply to Patrick Chen

TI__Mastermind 22745 points

Hi Patrick,

Yes, for your application, you should resend the PWM signal first, then power the IC. Please try again.

Regards

Sean

Power management

Power management forum

TPS61185: ISET switching issue