How to set LM3644 to Torch mode?

Power up HWEN and TORCH/TEMP pins, set reg0x01 to 0x9b, read reg0x0a is 0x80. Why?

Please help to check the HW design.

Hi Carl,

     There is a simple way to enable the torch mode, you just need to set the reg 0x01 to 0x8b and try again, or have you read the reg0x0A and 0x0B? Is there any reported error? 

BR

Sean

Hi Sean,

    After power up HWEN and TORCH/TEMP, set reg0x01 to 0x8b, read the reg0x0A is 0x00, read the reg0x0B is 0x02, read reg0x01 is 0x8b.

    LEDs are still not working.

BR 

Carl

Hi Carl,

    Reg0x0B is 0x02, which means "OVP" fault, have you checked your board or have you connect the LEDs for testing?

BR

Sean

Hi Sean,

   1. Sorry, Reg 0x01 read is 0x83, not 0x8b.

    2. Yes, I have connect the LEDs for testing.

BR

Carl

Hi Carl,

    Please check why there is "OVP" error and you can also try to change the torch current to a higher value.

BR

Sean

Hi Sean,

    Please help to check the hw design above.

    Does any of the following pins need be powered up when set to torch mode? (TORCH/TEMP,  STORBE, HWEN, TX).

BR

Carl

Hi Carl,

     You just need to power on "HWEN" pin, and float "Torch/temp" ,"Strobe". "Tx" pin. Just use the reg 0x01 to configure into torch mode.

BR

Sean

Hi Sean,

    Thanks alot for your help.

    After check the HW design, LED1 is not connect to LED, so set reg0x01 to 0x8a, OVP error no longer exists.

BR

Sean

Hi Carl,

    Is there any update? have you found the root cause?

BR

Sean