Hi,
I am using a teensy 3.2 to control 8 x 100W LEDs. The LEDs are connected via Boost converters to a common power supply (24V). The boost converter allows to dim the LED via a PWM input. Each converter gets its own PWM signal from the teensy to allow for different brightness levels per LED. I am using all channels of FTM0 on pins 5,6,9,10,20,21,22 and 23. Currently the PWM has a frequency of 6kHz and a resolution of 4095 steps.
Dimming per channel works although I have the problem that all channels have their rising edge at the same time and thus introduce a huge spike for the power supply. This introduces a big ripple on my supply line which causes some flickering down the road.
My idea was to phase shift the rising edge per channel or group of channels to even out the load the power supply sees within the duty cycle.
e.g. chan0 has ist rising edge on 0%, chan 1 at 12.5%,chan2 at 25% ..chan7 at 87.5%
I looked into the FTM0 timer functions and assume something like this could be possible by changing the FTM0_CnV channel value or maybe using one channel for the rising edge and one for the falling edge and thus having 4 phase shifted PWMs.
As I am quite new to the Flexible Timer structure that teensy I'd appreciate if someone more knowledgeable could give me a hint or an example of a phase shifted PWM. Or any other tip on how I could even out the load for the power supply.
thanks!
Links:
Boost converter Led Senser Xtreme
https://pcb-components.de/led-aufwa...d-senser-xtreme-200-2050ma-6v-30v-detail.html
LED Bridgelux Vero29 BXRC-56G10K0-L-24
https://www.digikey.com/products/en?keywords= BXRC-56G10K0-L-24
I am using a teensy 3.2 to control 8 x 100W LEDs. The LEDs are connected via Boost converters to a common power supply (24V). The boost converter allows to dim the LED via a PWM input. Each converter gets its own PWM signal from the teensy to allow for different brightness levels per LED. I am using all channels of FTM0 on pins 5,6,9,10,20,21,22 and 23. Currently the PWM has a frequency of 6kHz and a resolution of 4095 steps.
Dimming per channel works although I have the problem that all channels have their rising edge at the same time and thus introduce a huge spike for the power supply. This introduces a big ripple on my supply line which causes some flickering down the road.
My idea was to phase shift the rising edge per channel or group of channels to even out the load the power supply sees within the duty cycle.
e.g. chan0 has ist rising edge on 0%, chan 1 at 12.5%,chan2 at 25% ..chan7 at 87.5%
I looked into the FTM0 timer functions and assume something like this could be possible by changing the FTM0_CnV channel value or maybe using one channel for the rising edge and one for the falling edge and thus having 4 phase shifted PWMs.
As I am quite new to the Flexible Timer structure that teensy I'd appreciate if someone more knowledgeable could give me a hint or an example of a phase shifted PWM. Or any other tip on how I could even out the load for the power supply.
thanks!
Links:
Boost converter Led Senser Xtreme
https://pcb-components.de/led-aufwa...d-senser-xtreme-200-2050ma-6v-30v-detail.html
LED Bridgelux Vero29 BXRC-56G10K0-L-24
https://www.digikey.com/products/en?keywords= BXRC-56G10K0-L-24