TLC6C598-Q1: TLC6C598-Q1 Available PWM dimming ratio

Ryuuichi machida

Part Number: TLC6C598-Q1

Hi,

Let me confirm about below.

"When data is high, the DMOS transistor outputs are capable of sinking current. This pin also can be used for global PWM dimming."

According to datasheet there is above description in "8.3.7 Output Control".

This means user can perform PWM dimming for LED.

However, there is no description about PWM dimming ratio.

I think that this spec is related to AC spec of "RCK" pin. (Ex, if user require PWM=100Hz w/ 10 bit(1024 shades of gray), then frequency for "RCK" should be 102.4kHz. (I'm not sure 102.4KHz is available for "RCK"...))

But, specification for "RCK" is NOT described in datasheet as well.

So, could you please tell me there is limitation for gray level ?

Best Regards,

Machida

over 7 years ago

0 Ryuuichi machida over 7 years ago

Guru 11855 points

Hi,

If you can not give comment about my previous question, could you please confirm following question at least ?

* Is there any limitation about "RCK" ?
Especially, we would like to know whether there is limitaion about "ON time" of RCK pulse.

Best Regards,
Machida

0 Ryuuichi machida over 7 years ago in reply to Ryuuichi machida

Guru 11855 points

Hi,

Let me change my question. At first, please confirm following question.

* Is it possible to input same "On time" as SRCK to RCK pin as well ?

Thanks in advance,
Machida

0 YY over 7 years ago in reply to Ryuuichi machida

TI__Intellectual 2240 points

Hello LED Driver team,

Could anyone please follow this topic?

we are waiting the comment to propose this device to the customer.

Best Regards,

Yuki

0 Anda Zhang over 7 years ago in reply to YY

TI__Expert 5380 points

For PWM dimming, there are two ways to realize this function. If all 8 channels needs to be dimmed together, G pin can be used to realize this. Another way is using the serial interface to turn on all off channels, as the datasheet shows, the clock frequency is 10MHz max, minimum data write time can be around 1us, so there is no problem for the 100KHz RCK frequency.

0 Ryuuichi machida over 7 years ago in reply to Anda Zhang

Guru 11855 points

Hi Anda-san,

Thank you for your reply.

>so there is no problem for the 100KHz RCK frequency.

Is it any requirement for duty ratio or mininum ON time ?

In general, I guess that RCK is input from GPIO of MCU, so I want to confirm about this.

Thanks in advance,

Machida

0 Anda Zhang over 7 years ago in reply to Ryuuichi machida

TI__Expert 5380 points

As you know, if using RCK to turn on/off channels to realize the PWM dimming, the turn on/off time will be at least 8bits + Latch time, 1us will be enough, so 1us on time can be achieved, may i know what is the customer's requirements on the on time?

0 Ryuuichi machida over 7 years ago in reply to Anda Zhang

Guru 11855 points

Anda-san,

Thank you for your reply.
>may i know what is the customer's requirements on the on time?
I can send you customer's constitution. But this include customer's info, so I will send email privately.

Best Regards,
Machida

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TLC6C598-Q1: TLC6C598-Q1 Available PWM dimming ratio