TPS61160: PWM dimming ISSUE

CHO SR

Part Number: TPS61160

Hi,

The customer is using TPS61160 for LCD backlight.

When dimming is performed by changing the PWM, the LED_A outputs a voltage of 7.6 to 8.6V, but the LED brightness does not change.

Please raise the output of LED_A to 10V without changing the circuit and guide us to adjust the brightness with the PWM of CTRL.

The voltage range of LCD is 8.4~10.2V.

over 3 years ago

+1 Hardy Wu over 3 years ago

TI__Genius 12915 points

Hi CHO,

The LED is current driven type component, the voltage across LEDs are determined by the current flow through them. With 100% PWM input, the output current are set to max and voltage for LED backlight is also to max. I do not think there is a way to raise voltage on LED_A.

0 CHO SR over 3 years ago in reply to Hardy Wu

Genius 3415 points

Hi Hardy,

I'm sorry, but the customer asked a question.

Is there a way to increase the LED_A voltage by constructing an additional circuit in the current schematic diagram?

0 Frank Qiu over 3 years ago in reply to CHO SR

TI__Genius 15776 points

10.1 -10.7 is Chinese notional holiday, our expert will reply you after 10.8. if it's an urgent case, please directly communicate with the person who is assigned.

+1 Hardy Wu over 3 years ago in reply to CHO SR

TI__Genius 12915 points

Hi CHO,

Yes you can cascade a small resistor with LEDs in one series.

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TPS61160: PWM dimming ISSUE