TPS61169: minimum duty cycle and dimming on time spec

rock shen

Part Number: TPS61169
Other Parts Discussed in Thread: TPS61196

Hi,Sir:

Could you kindly help to check whether the TPS61169 had minimum duty cycle and dimming on time spec?

for example, even the minimum duty is 1% and PWM dimming frequency is 100KHz with 1 serial led(20mA),

that means a 0.1uS dimming on time with 1 serial led(20mA),

as the TPS61169 could be work well and the LCD's backlight function also be good?

Thanks!

0 Yuting Shao over 5 years ago

Hi Rock,

TPS61169 supports 1% to 100% for 100kHz dimming frequency.

BR,

Robin

0 rock shen over 5 years ago in reply to Yuting Shao

Hi,Robin:

Could the TPS61169 always show the minumum brightness when use 1% duty?

and the brightness is linely?

If no, could you kindly help to show the formula for the duty and brightness?

Thanks!

0 Yuting Shao over 5 years ago in reply to rock shen

Hi Rock,

ILED=Vfb/Rset, Vfb max. is 204mV and Vfb=duty cycle x 204mV.

For 1% duty, TPS61196 is analog dimming which means its accuracy at low brightness is a little bad.

BR,

Robin

0 rock shen over 5 years ago in reply to Yuting Shao

Dear Robin:

Which duty range does TI could guarantee?

and how is the bad status as the low duty as the 1%,

for example, the 1% duty maybe is more light than 2%?

or other phenomena？

Thanks!

0 Yuting Shao over 5 years ago in reply to rock shen

Hi Rock,

There is no data for this item, so we cannot give you a accurate value.

BR,

Robin

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