Driver IC for a TRIAC dimmable smart bulb?
Hi,
I am looking for a driver that would both be suitable for both TRIAC and PWM/linear dimming (from a microcontroller). The output needed is 10W at 70V (or below). Additionaly only off-the-shelf inductors should be used.
The challange i am facing is that anything but LYTSwitch-0 has complex internal blocks, so the only predictable way i can think of controlling the output current is using a transistor in series with the current sense resistor.
With LYTSwitch-0 i could make the microcontroller part of the control loop, measuring phase angle, LED current, and producing the binary skip/no-skip feedback signal to the LYT0006D. PFC and an active bleeder would also be simple additions. The active bleeder might not even be required, since a buck-boost LYT0006D with Vout=70 should be able to work down to 30 Vin, or to put it another way: able to draw current for 94% of a 230 VAC cycle (89% for 120 VAC).
Last thing would be adding the input dampening, maybe even active.
Is this a good idea?
If so could you point me to some resources on the LYTSwitch-0 in buck-boost mode. I haven't been able to find any reference designs / PI expert online support.
Hello,
Thank You for your Interest on Power Integrations LED driver IC. Adding transistor in series with sense resistor may not work on start-up or transient due to it is a normally open device. I would recommend adding a MOSFET across the sense resistor for PWM control. Drive the MOSFET in linear region to vary the sense resistor value. However this topology is non-isolated, so you need an Isolation if your PWM dim input is user accessible. For buck-boost design, you can refer to the application note AN60. Here is the link: https://led-driver.power.com/sites/default/files/product-docs/an60.