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LM36011: for infrared illumination

d_zero
Genius 4470 points
Part Number: LM36011
Other Parts Discussed in Thread: TPS54201

Dear *,

Is the LM36011 a good choice to use with IR LED?

1)

We have a 3.5V to 4.2 input voltage.

How is the V_LED voltage regulated ( in the DS in tables i see that Vled is 3.4V)? or do we only have to set the desired current eg 350mA?

2) what is the default mode of the led driver is it disabled?,to enable the output current/voltage then we have to set the bit0,1 (0x01) through I2C  eg. 11 (flash) and bit 3 to 1 (edge triggered) and then we need to pull the strobe signal high?

Best Regards,

D.

  • 0
    TI__Mastermind 22745 points
    Hi D_zero,
    1. Yes, LM36011 work on bypass mode, the extra voltage between Vin and VLED will drop on the internal current sink. By the way, which mode you want to work with?
    2.The default mode is the stand by mode. You need to enable the output with reg 0x01. Strobe pin was used to use the external signal to trigger the flash pulse.
    Regards
    Sean
  • 0 in reply to Sean Zhou
    Genius 4470 points
    Hi Sean,

    i think we will use the strobe signal for enable. So 0x01 bit 2 has to be set to 1 ( and bit 3 to 1 for precise timing), and then put the driver to desired mode with 0x01 bit 1and0(torch or flash) , and then the driver is waiting for strobe high signal, is that correct?

    Br,
    D.
  • 0 in reply to d_zero
    Genius 4470 points
    Hi Sean,

    is the LM36011 linear driver?

    What is the right way to calculate the dissipation on the driver if a input voltage is 3.7V and the Vled is 1.9V @ 350mA?

    In this case what is the value of input current?

    if we want to lower the dissipation is a led driver in buck mode better choice?

    Br,
    D.
  • 0 in reply to d_zero
    TI__Mastermind 22745 points
    Hi D,

    Yes, your understand is right.you can think LM36011 as an linear driver. when Vin=3.7V and Vout=1.9V, the votage drop of 3.7V-1.9V will drop on the current sink. The power cnsumption on current sink is (3.7V-1.9V)*350mA。

    Regards
    sean
  • 0 in reply to Sean Zhou
    Genius 4470 points
    Dear Sean,

    is there a driver that has lower dissipation (i guess buck mode) that has i2c and strobe signal?

    Do you have any recommendation?

    Best Regards,
    David.
  • 0 in reply to d_zero
    TI__Mastermind 22745 points
    Hi David,

    I'm sorry that we don't have such buck led flash driver with strobe pin. But we have one general led driver with buck topology TPS54201.

    Regards
    Sean