Regarding backlight pins of CFA320240F-T-TS

[vinodxx]

I want to use CFA320240F-T-TS in my pic32 board.
Why backlight pins are used.
What if I leave backlight pins unconnected or grounded.
Sorry for the naive questions.

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[CF Support2]

The CFAF320240F-T-TS needs to have the backlight on in order to read the display. Without the backlight, the display "can: be read, but it is very dark. There are several options in driving the backlight voltage / current.

We use a PWM backlight control on some of our intelligent modules. It is an acceptable way to control the brightness via software. Basically there are no problems. The only only that we've seen is that for some backlights, at certain settings, there is a slight flicker to the backlight. One 'step' higher or lower, no flicker. Lifespan of the LEDs is related to current. Driving with PWM effectively reduces the current. Over the years, we have not seen any measurable difference in the life of a PWM controlled LED vs one that is not.

A better solution would be to use a current driver. For one we can recommend the NCP5007 Compact Backlight LED Boost Driver which can be found at the link below:

http://www.onsemi.com/PowerSolutions/product.do?id=NCP5007SNT1G

Other possible parts:
http://www.linear.com/pc/productDetail.jsp?navId=H0,C1,C1003,C1094,P37356
http://www.maxim-ic.com/quick_view2.cfm/qv_pk/3719
http://www.national.com/pf/LM/LM3530.html
http://www.semtech.com/products/power_management/led_drivers/boost_led_drivers/sc4540/