Unconnected pins in LED Driver

[FreshmanNewbie]

I am exploring a 4-channel LED Driver IC for my LCD backlight and found this part in Digikey.

However, I don't want to use that part for biasing my LCD. So, I do not want to use the below marked pins.



However, reading the datasheet, I am not clear on how to take care of those marked pins if I don't want to use them. Also, I do not want to use the PWM control for brightness control of my LED backlight.

I just need to drive the backlight.

Hence, the major thing I would like to know is how to take care of the above-marked pins if not used.

The next thing is that my LED Backlight has 4 strings. The total typical current mentioned in the LED backlight section of display datasheet is 160mA, which I assume as 40mA typ per string.

Also, the Display datasheet does not have LED current curves.

One confusion is that, is it really not necessary to drive the LEDs at the 40mA typ per string as, additional current produces more heat than light. Also, the max current of the TI LED driver is 30mA per string.

So, would you advice to drive 30mA per string (which is the max that the TI part offers) for a 40mA per string ? Would it be OK, fine?

To summarise, 2 questions:

1. What to do with the unused pins?
2. Whether I can drive the max 30mA per string (since its the max of 30mA, I may not get the complete 30mA per string?) whether the display LED backlight requires typ of 40mA?

 

[FvM]

My datasheet reading says, all LEDs are disabled on register reset (see Table 18). If so, the device would be useless without I2C control.

 

[FreshmanNewbie]

1. So you mean to say that without I2C control, this IC is useless?

My datasheet reading says, all LEDs are disabled on register reset (see Table 18). If so, the device would be useless without I2C control.

2. Suppose, I use the same I2C that goes to the display touch panel for this driver also, would that be possible?Would that work?

 

[dick_freebird]

I have to wonder why you want to use this fancy part while not
using most of its fanciness. Why not a simpler backlight driver?
Just trying to save a dime by wasting a day?

 

[KlausST]

Hi,

2. Suppose, I use the same I2C that goes to the display touch panel for this driver also, would that be possible?Would that work?

I2C is a communication bus. So
* connecting the bus is one thing
* but "communication" is the other thing that needs to be done.

The datasheet tells what commands need to be processed for the driver to work as desired.

Klaus