Complementary PWM

[sabu31]

Dear All,

I wanted to know if there is a method to obtain complementary PWM using ESP32. The typical pulse width needs to be 5 to 10 micro-sec. Using GPIO, it is possible to generate complementary PWM( using GPIO High, Low). But there is overlap of 1micro-sec. Also the observed frequency in Oscilloscope is different from what is calculated (especially at lower pulse width).

I presently have ESP-WROOM-32. On searching net, there seems to be an option named MCPWM, but cannot find a library for the same where searching in Arduino IDE.

Motor Control Pulse Width Modulator (MCPWM) - ESP32 - — ESP-IDF Programming Guide latest documentation

Please let me know how to resolve this issue.
Thanks & Regards,

 

[FenTrac]

In the Arduino IDE, under "sketch-include library-manage libraries" try a search for esp32motorcontrol.

https://www.arduino.cc/reference/en/libraries/esp32motorcontrol/

 

[dick_freebird]

Are you against doing this in external hardware?

For example some MOSFET drivers come with A and !B
inputs so you can have either true or inverting output,
and using a pair (or a dual) can get you to tens of ns
delay match.

The question to me is whether you need any independence
of the phases or they are always complementary lock-step.

Since you're not going to drive a motor directly from any
processor pin, I'd think more about "points of opportunity"
down the line in the power train.

 

[sabu31]

Are you against doing this in external hardware?

For example some MOSFET drivers come with A and !B
inputs so you can have either true or inverting output,
and using a pair (or a dual) can get you to tens of ns
delay match.

The question to me is whether you need any independence
of the phases or they are always complementary lock-step.

Since you're not going to drive a motor directly from any
processor pin, I'd think more about "points of opportunity"
down the line in the power train.

I need complementary PWM with may be 50ns or more deadband. The pulse width required is 5us. Is there any method to use LEDC PWM and use some external hardware IC for generation of deadband+ Complementary PWM

 

[KlausST]

Hi,

Is there any method to use LEDC PWM and use some external hardware IC for generation of deadband+ Complementary PWM

I guess dick_freebird already answered this:

some MOSFET drivers come with A and !B
inputs so you can have either true or inverting output,
and using a pair (or a dual) can get you to tens of ns
delay match.

Go to your electronics distributor site and do a search. There are some with fixed dead time and some with adjustable dead time.

Klaus

 

[dick_freebird]

You can make a "break before make" timing logic with SSI CMOS
gates, but getting to exactly and consistently 50ns is going to want
more - probably passives-determined, or an active servo to get the
outcome you want. Because too little or too much each have their
cost.

What about a low cost bridge driver, which (having both stages
under one roof) can do tighter nonoverlap perhaps? Not sure what's
out there for range and tolerances, these days.