LM3643: LM3643 - force flash mode for high current (several minutes)

Frank Bolton

Part Number: LM3643
Other Parts Discussed in Thread: LM3410

Hi,

I want to drive a set of 4x high power LEDs at about 700mA (one at a time at i2c configurable current) using power from a single lithium cell (3.7V).

The LM3643 and LM3643b each driving two LEDs look like a great candidate when used in Flash mode. Our current LED driver also has a flash and a torch input and we are able to use the higher current so long as the device is within acceptable temperature ranges.

Is there a way to force the torch mode to not time-out?
(That is to bypass / ignore the settings in SNVS967A - 9.6.8 Timing Configuration Register (0x08) )

Alternatively- I'd be happy for recommendations of LED drivers that might achieve what I need without the time-out pain.

over 5 years ago

0 Sean Zhou over 5 years ago

TI__Mastermind 22745 points

Hi Frank,
Due to the high current application, there will casue a thermal issue without Time out Setting. Our device can only support high current application with time out. So what's the longest time that you need to out continuous 700mA?
Sean

0 Frank Bolton over 5 years ago in reply to Sean Zhou

Prodigy 45 points

Hi Sean,
We need to run 700mA at a steady state level (on for as long as 30 minutes).
This makes me think that a different IC would be more appropriate for my needs.
Do you have any suggestions of devices that are i2c controlled (variable current), and work from a similar voltage range to the LM3643?

Best,
Frank

0 Sean Zhou over 5 years ago in reply to Frank Bolton

TI__Mastermind 22745 points

Hi Frank,

Do you necessary need I2C interface. we have another LM3410 which can output up to 1.5A for a long time. And this device has integrated PWM control, you can use PWM to change the current.

Sean

0 Frank Bolton over 5 years ago in reply to Sean Zhou

Prodigy 45 points

Hi Sean,

Thank you for the recommendation.
I'll check with the rest of the design and will consider the recommended part (possibly including an i2c PWM IC).

Frank

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LM3643: LM3643 - force flash mode for high current (several minutes)