TPS61195: FDIM termination

Takahiro Saito

Expert 5435 points

Part Number: TPS61195

Hello team,

When TPS61195 is used with analog dimming mode, how shoud I terminate the FDIM pin?

Is it okay to left open the FDIM pin?

Regards,

Saito

over 5 years ago

0 Sean Zhou over 5 years ago

TI__Mastermind 22745 points

Hi Takahiro,

Please connect a resistor to GND when use the analog dimming mode.

Regards

Sean

0 Takahiro Saito over 5 years ago in reply to Sean Zhou

TI__Expert 5435 points

Hi Sean-san,

Thank you for your answer.

When the analog dimming is used, TPS61195 doesn't use the internal PWM dimming frequency.

So, can I use any register value for RFDIM (40k~1Mohm) when analog dimming mode is use?

Regards,

Saito

0 Sean Zhou over 5 years ago in reply to Takahiro Saito

TI__Mastermind 22745 points

Hi Saito,

Yes, you can use those value.

Regards

Sean

0 Takahiro Saito over 5 years ago in reply to Sean Zhou

TI__Expert 5435 points

Hello Sean-san,

Can I add question relate to my last question? Customer will use analog dimming mode. In this case, R_FDIM is no relationship with the dimming behavior.

Customer wants to use 10kohm for FDIM because they wants to re-use schematic of past project.

R_FDIM = 10kohm is out of range of 40kohm - 1Mohm that is recommend range of R_FDIM.

What will happen when customer uses R_FDIM = 10kohm in analog dimming mode?

Is the curent consumption through R_FDIM just increased? Could you confirm if the FDIM pin is not damaged and the device doesn't enter abnormal operation?

Regards,

Saito

0 Sean Zhou over 5 years ago in reply to Takahiro Saito

TI__Mastermind 22745 points

Hi Saito,

No, it will not open the internal current sink and this will not cause the leakage current through "FDIM". So please go ahead, 10kohm is ok for analog dimming mode.

Regards

Sean

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TPS61195: FDIM termination