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Space saving LCD-TFT Backlight LED driver

Other Parts Discussed in Thread: TPS61194, TPS61165

Hi,

We needed  an LED driver for supplying the backlight of an LCD TFT display of part#: NHD-5.0-800480TF-ATXL# .

The required specifications are:
Vout= 19.2V

Iout= 60mA
Vin(min)=5V
Vin(max)=9V


Special features required:
Output open-circuit & short-circuit protection
PWM Dimming
Input Over-voltage,Under-voltage protection

We've found TI part# TPS61194 satisfying these.

But, the overall circuit size would be very high if we use it.

Do we have a better solution?

Please look into it.

Thanks.

Emil Zacharia George

  • Hi Emil,

    I took a look at your TFT display spec and saw the display has 3 strings of 6 LED series each.  But I also noticed that display has a single LED+ and LED- pin connection, meaning the strings are all shorted in parallel internal to the display.  So that means you only need a device with a single LED current channel to drive 60mA for the combined LED load..  For these type of LED loads the TPS61165 device is what is normally used.  The TPS61165 uses an external current setting resistor to set the maximum LED current and also uses a PWM input to dim the LED dc current based on input duty cycle.  This should be the simplest/smallest device to meet your requirements.

    Thanks,

    Jeremy

  • Thank you for the suggestion. Will look into it.