Other Parts Discussed in Thread: LM3409EVAL, LM3409
Good morning,
I'm looking to create a fast LED driver for a machine vision application and wondered if you'd be able to help with specifying a suitable driver and reviewing my current setup.
Our requirements are as follows:
> VIN: 15V - 30V max
> VOUT: VF = 12V - 14V max
> ILED: Must swing between a maximum of 0 - 1A with minimal ripple (ideally, a rise and settling time of between 1 - 2us with LED ripple ~1% would be great but possibly unachievable)
> MAXIMUM LED SWITCHING SPEED: We'd like to have the LED on for 10us and then off for say 10-20us. (ton = 10us, toff = 10-20us, trise/fall = 1 - 2us)
> CONTROL METHOD: Ideally analog dimming (whilst not as fast as PWM, the LED output current tends to be more stable when using analog dimming opposed to PWM)
We've been testing the LM3409EVAL to try and achieve this response however, we notice a significant rise in LED current ripple once we try to move past 20kHZ LED switching frequency when using PWM. Analog dimming is noticeably worse at lower switching frequencies.
Thanks for your help in advance.
Kind regards,
Connor