LP5816: Duty cycling to go above maximum current?

Cameron Wutzke

Part Number: LP5816
Other Parts Discussed in Thread: LP5861T

Tool/software:

Hey Team! I'm a bit confused how this device works. Sorry I made a typo and the device should be LP5816T

I was also wondering if we wanted to use this part to drive 12 LEDs and have a 5% duty cycle on those LEDs, could we sink > 125mA? curious if there is a way to achieve this

We would use 12 individual current sinks and not the full 18 channels so I was wondering if we can therefore increase the max current to be >125mA especially if we are only driving for a 5% duty cycle.

2 months ago

0 Felix Wang 2 months ago

TI__Expert 6500 points

Hi Cameron,

I think you refer to the LP5861T, right?

No, the maximum current for each current sink is 125mA when MC = 7, CC = 127 and DC = 255. So can not achieve > 125mA current. May I know how much current is required?

As for the 5% duty cycle that can be realized through setting the PWM value as 12 in 8-bit mode.

Thanks and best regards,

Felix

0 Cameron Wutzke 2 months ago in reply to Felix Wang

TI__Expert 3852 points

About 200mA would be interesting. Could we tie two current sinks together to sink 200mA total on one LED string? Curious if there's an issue or tradeoff with this approach

+1 Felix Wang 2 months ago in reply to Cameron Wutzke

TI__Expert 6500 points

Hi Cameron,

Yes, two channels can be paralleled to sink 200mA total current. Only tradeoff is occupying two channels, so drive 12 LEDs require total 24 channels that will need 2 pieces of LP5861T.

best regards,

Felix

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LP5816: Duty cycling to go above maximum current?