using stm32wl55ccu to drive 3 phase bldc

[YY55]

Hi ,

I am using stm32wl55ccu 48 pin QFN MCU to drive a 3 phase brushless motor using 3-phase complementary PWM output signals using TIMER 1. I have seen at the datasheet that this 48 QFN package is missing the complementary output of TIMER1 ,Channel 3, TIM1_CH3N (which is present at the BGA version). Is it possible to generate the 3-rd phase complementary output PWM signal in another way ?(like using timer 2 in a master/slave configuration).

Thank you, Joe.

[DBE · Accepted solution]

Hello YY55,

It is technically possible to synchronize TIM1(master) and TIM2(slave), examples are available in the reference manual of the chip (chapter 24.3.26 and 25.3.19):

https://www.st.com/resource/en/reference_manual/rm0434-multiprotocol-wireless-32bit-mcu-armbased-cortexm4-with-fpu-bluetooth-lowenergy-and-802154-radio-solution-stmicroelectronics.pdf

But your firmware will have to take care about the deadtime insertion between the high side and low side on the third phase (which will be done automatically on phase 1 and 2 by TIM1 in your case).

Another solution could be to choose (if possible), a gate driver that needs only 3 PWM input signals ( like L6230: https://www.st.com/en/motor-drivers/l6230.html ) 

Best regards