TPS61165: the range of duty cycle by using PWM dimming

nick lin

Part Number: TPS61165

HI,

We are using TPS61165 as my panel's LED driver.

I saw the maximum duty cycle is written in electrical characteristics table. but i didn't see the minimum duty cycle value.

Can anyone advise the minimum value of duty cycle?

thanks

Nick

over 7 years ago

0 Harini Sankabattula over 7 years ago

TI__Intellectual 1780 points

Hi Nick,

Minimum on pulse width (datasheet page # 5) is 40ns
TPS61165's boost converter runs at a fixed switching freq of 1.2MHz => 833.33ns

So, minimum duty cycle = 40ns/833.33ns = 4.8%

Please let me know if there are any further questions.

Best,
-Harini

0 nick lin over 7 years ago in reply to Harini Sankabattula

Prodigy 60 points

Hi Harini,

Thanks for your response.

I think I have mistake.

The Frequency and Maximum duty cycle shown in "Voltage and current control" table of datasheet, I think it is belong power switching characteristic.

What I want to know is, the range of duty cycle I can apply to CTRL PIN by using PWM dimming.

Sorry for my mistake.

thanks

Nick

0 Harini Sankabattula over 7 years ago in reply to nick lin

TI__Intellectual 1780 points

Hi Nick,

The minimum duty cycle can be pretty low - around 50ns PWM input on time. Below this, the internal glitch rejection on the CTRL (PWM input) can cause pulses to be skipped and you may run into the risk of accidentally triggering the 1-wire interface.

Please refer to an App note on this:
www.ti.com/.../snva769.pdf

To ensure proper detected logic levels, keep the pulse width above 50ns (say 100ns to be safe).

Best,
-Harini

0 nick lin over 7 years ago in reply to Harini Sankabattula

Prodigy 60 points

Hi Harini,

With the document you provided, it is clear to me.

thanks for your help.

Nick

Power management

Power management forum

TPS61165: the range of duty cycle by using PWM dimming