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+--- Thread: Max PWM frequency (/showthread.php?tid=6891)
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Max PWM frequency - kepten - 10-19-2024
Hi, does the B16M board support dimming LEDs with 20kHz PWM (up to 10A/channel load)? If not, what is the maximum PWM frequency that can be used without overheating/burning the MOSFET/driver/microcontroller/etc?
Regards,
Robert
RE: Max PWM frequency - admin - 10-20-2024
sorry, B16M mosfet output can't use for PWM output, because of ESP32-S3 conenct with i2c PCF8575 extender chip , then connect with 10A mosfet. Use ON/OFF is better. But B16M have free GPIOs on board, that can use for PWM output, just without driver.
if you want to use dimmer , suggest you chose KC868-AP or KC868-D16 dimmer controller.
RE: Max PWM frequency - kepten - 10-20-2024
(10-20-2024, 02:16 AM)admin Wrote: sorry, B16M mosfet output can't use for PWM output, because of ESP32-S3 conenct with i2c PCF8575 extender chip , then connect with 10A mosfet. Use ON/OFF is better. But B16M have free GPIOs on board, that can use for PWM output, just without driver.
if you want to use dimmer , suggest you chose KC868-AP or KC868-D16 dimmer controller.
What is the max PWM frequency usable with KC868-AP and KC868-D16? I think for KC868-AP it should be ~1.5kHz since it is the limitation of PCA9685. What about KC868-D16?
I'm using 20kHz now with a custom esp-32 based PCB with MOSFET driver IC in order to avoid any hearable humming noise from the power supply. Is there any Kincony product which can support such PWM frequency (and a couple of Amperes load)?
RE: Max PWM frequency - admin - 10-20-2024
we have ESP32 board can output PWM, but without "a couple of Amperes load". Maybe you need to add your own driver.
KC868-D16 is dc 0-10v output dimmer controller, NOT output PWM, it's made by ARM STM32 CPU, not use ESP32 CPU.
RE: Max PWM frequency - kepten - 10-21-2024
(10-20-2024, 11:36 PM)admin Wrote: we have ESP32 board can output PWM, but without "a couple of Amperes load". Maybe you need to add your own driver.
KC868-D16 is dc 0-10v output dimmer controller, NOT output PWM, it's made by ARM STM32 CPU, not use ESP32 CPU.
Thanks.
I tried but coulnd't find any ready-made boards with MOSFET drivers on them (this Quinled is supposed to be one but it's not available yet as a pre-assembled board).
Do you plan to create a Kincony dimmer board which would have beefy MOSFETs and driver ICs so it could handle 3-5A/channel at 20kHz? I think this is a "market gap" at the moment.
RE: Max PWM frequency - admin - 10-21-2024
Do you use for DC load or AC load? can you list load type in details.
RE: Max PWM frequency - kepten - 10-21-2024
(10-21-2024, 07:41 AM)admin Wrote: Do you use for DC load or AC load? can you list load type in details.
I use 12V (DC) LED strips and bulbs in my flat for lighting. Some are 5m+ long or have 10+ bulbs in parallel therefore they consume a couple of Amperes at full brightness. Usually I don't need full brightness, so I'd like to be able to dim them. Right now I have 3x240W 12V power supplies each feeding a subset of the lamps/LEDs. They are being dimmed/PWM-ed with a MOSFET driver connected directly to ESP GPIO, driving a 70V, 10A N-channel MOSFET. That way even at 20kHz, no heat sink is needed.
I'm not able to find any good alternative for this use case. Seemingly all the commercially available LED dimmers/boards max out at ~1-2kHz (I guess because they don't use MOSFET driver IC). I could achieve 20kHz+ frequency dimming with dimmable PSUs but I'd need ~20 of them which would be ridiculously expensive compared to the current 3x240W PSU setup.
RE: Max PWM frequency - admin - 10-21-2024
why not use KC868-AP? it have 10A driver on PCB. it can drive your LED strip.
if you think power is not enough. you can use KC868-D16 + LED Driver (MAX have 250W version), it enough for LED strip to use.
RE: Max PWM frequency - kepten - 10-21-2024
(10-21-2024, 12:28 PM)admin Wrote: why not use KC868-AP? it have 10A driver on PCB. it can drive your LED strip.
if you think power is not enough. you can use KC868-D16 + LED Driver (MAX have 250W version), it enough for LED strip to use.
AFAIK KC868-AP cannot PWM at 20kHz since it is using PCA9685 (which can do max ~1.5kHz).
KC868-D16 should be able to output a 20kHz PWM signal but which LED Driver would support that frequency without overheating? Can you give me specific product links?
RE: Max PWM frequency - admin - 10-21-2024
https://www.kincony.com/16-channel-tuya-dimmer-module.html
https://www.kincony.com/how-to-use-kc868-d16-dimmer-controller.html
about KC868-D16, it's output 0-10v, you can chose a suitable driver for KC868-D16.