Senthamizhan.K,
I think if you look closely, we say 'Do Not Populate' around only R7, not the FETS. That means, do not populate resistor R7. FET Q2 supplies power to the backlight. You will notice that LCD_VEEEN contros Q1, which in turn controls Q2. So, LCD_VEEEN controls whether or not 5V is supplied to the backlight inverter.

When the LCD controller driver gets powered down, both LCD_VDDEN and LCD_VEEEN are de-asserted (go to '0' state).

We do provide part numbers for these components. Please look at the 'LCD-5.7-QVGA-10 BOM', which is located next to the schematic on the download page for this display kit. http://www.logicpd.com/downloads/786/1005106_Rev_A.pdf

Regards,
-Mike

Hello
Thanks for this quick response.Really Sorry.We are using LCD-3.5-QVGA-10 Diaplay kit and the zoom 7A400-10 starter development kit .During boot time and Suspend the backlight of the LCD is off.We think that the signal named LCD_VDDEN from zoom 7A400-10 starter development kit to the Display kit control this function.Are we right?Is there any relationship between suspend action and backlight off?.If it be so, why are you said that "don't populate" for the MOSFET section in your diaplay kit reference degign and There is also no part number for Q1 & Q2.Please give us your suggestion.

with regards
Senthamizhan.K
Pico Mega Design Labs
chennai.

Senthamizhan.K,
I think if you look closely on the schematic on the website ( http://www.logicpd.com/downloads/228/ ), we say 'Do Not Populate' around only R2, not the FETS. That means, do not populate resistor R2. FET Q2 supplies power to the backlight. You will notice that LCD_VDDEN contros Q1, which in turn controls Q2. So, LCD_VDDEN controls whether or not BL_VCC is supplied to the backlight inverter. This kit was done a little differently than our other display kits, we do not do power managment to the display.

When the LCD controller driver gets powered down for suspend, both LCD_VDDEN and LCD_VEEEN are de-asserted (go to '0' state).

*Please make sure you design to the Sharp datasheet for proper power sequence for this display. These kits are meant for development purposes. If you have questions about proper power design for this display, recommend talking to your local Sharp support.


Q1 - Fairchild NDS351AN
Q2 - International Rectifier IRLM5203

Regards,
-Mike