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LM36274EVM: LM36274

Ashish Shrivastav
Prodigy 220 points
Part Number: LM36274EVM
Other Parts Discussed in Thread: LM36274

I am not able to enable light load PFM switching. 
Typical load requirement is less than 8mA/ ch and need PFM to enhance the battery life. Is there any register to specifically enable auto PFM/PWM ?
Do you suggest another part with PFM features.

  • 0
    TI__Intellectual 2140 points

    Hi,

    This device does not incorporate a PFM mode. However, it provides the following options to increase efficiency at low LED current:

    1. Backlight switching frequency settings of 500kHz or 1MHz, via an I2C register bit. If the maximum output current is lower, you may select the 500kHz option to optimize efficiency.

    2. Two Auto Frequency adjustment settings, via I2C registers. You can choose 2 LED current thresholds below which the backlight boost frequency will be reduced to 500kHz and 250kHz, respectively. The thresholds you select would depend on the LED configuration used (# of strings and # of LEDs per string) and the backlight boost inductor. For guidelines and some examples of selecting these settings refer to section 7.3.2.6 of the datasheet.

    This is probably the best device for your application, especially if you are utilizing the LCM bias.

    Regards,

    Angelos Tsiros

  • 0 in reply to Angelos Tsiros
    Prodigy 220 points
    Thank you Angelo !
    I appreciate your response.
    I can try Auto frequency adjustment, it sounds interesting.
    Also, I checked the datasheet, it seems to be a limited one with no section 7.
    Where could I download the entire datasheet?
    Thanks again !!!
  • 0 in reply to Ashish Shrivastav
    TI__Intellectual 2140 points

    The datasheet you downloaded is only a brief version. To request the full version, click on the product folder name and then on the "Request LM36274" link under Special Notes.