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TLC5916/17 application question

Other Parts Discussed in Thread: TLC5916, TPS75105


I am looking for an LED driver that can drive four (4) blue LEDs, each at a DC current of 5mA.  Forward voltage at 5mA is 2.8V typical (3.4V max).  Due to variations in input voltage from the vehicle (8-32V), I was thinking of doing 4 separate channels running off the 5V rail.  I need constant-current control and also the ability to dim the LEDs.

Does anyone have any recommendations for this application?  I was looking at TLC5916/5917 for this application as it had analog dimming and was showing a 3mA to 150mA range.  Is the 3mA minimum range in reference to the maximum DC current (5mA in our application)?  Or does the DC current level even during analog dimming have to remain above 3mA?  If the latter, with a minimum dimming of 1/12th, I assume this would mean the max DC current would need to be ~28mA to stay above the minimum of 3mA and this device would not work in our application.

Thanks again!


  • Hi Paul,

    We have a number of ways to possibly do this.  To help refine the search, can you help answer a few questions:

    • Input voltage range: you mentioned 8-32V, or potentially 5V?  Do you already have a 5V supply available, or would this need to be added or integrated into the LED driver? For starters, you might look at TPS75105.  It is a 4-channel LED driver which can operate from 5V with two PWM dimming inputs (each PWM input controls two of the LEDs, so if all 4 need individual control, this might not be the best option).
    • Is this an automotive application? "from the vehicle (8-32V)" was mentioned.
    • How are you looking to control the LED brightness?  individual PWM inputs, or via SPI, I2C, other?  The TLC5916/17 use a SPI interface.
    • Are protection feature(s) required - LED open, LED short, thermal protection required?



    • We have a 5V supply rail available
    • LED control can be PWM or SPI
    • All 4 LEDs can be dimmed together, individual control is not required.
    • LED open protection if the device can be damaged by an open.  Other protections not required.
    • Our maximum DC current per LED is 5mA.  Want to be able to dim down from there.