Two PWM outputs, same period & polarity, 180 out of phase
- Mark as New
- Bookmark
- Subscribe
- Mute
- Subscribe to RSS Feed
- Permalink
- Email to a Friend
- Report Inappropriate Content
2011-08-05 3:00 PM
I'm using the STM32F103RCT6. I need two PWM outputs, where the period and polarity of each is the same, but one output is 180� out of phase from the other.
A duty cycle change must affect both concurrently. The complementary output configuration is close, but not quite.
I need to be able to do this:
Any ideas?
#stm32-pwm- Labels:
-
TIM
- Mark as New
- Bookmark
- Subscribe
- Mute
- Subscribe to RSS Feed
- Permalink
- Email to a Friend
- Report Inappropriate Content
2011-08-05 4:45 PM
Errrm, isn't that really a wish for two in-phase PWM outputs, one with the opposite polarity. The duty cycle of the second is the complement of the primary duty cycle.
There are several ways to synchronize the phases. The most sophisticated (overkill for this simple task) is using the ''commutator'' ability -- PWM values can be sequentially pre-loaded into registers, and then activated simultaneously. But with only two signals you have many simpler choices.- Mark as New
- Bookmark
- Subscribe
- Mute
- Subscribe to RSS Feed
- Permalink
- Email to a Friend
- Report Inappropriate Content
2011-08-10 4:26 PM
If they were in phase with opposite polarity, when one output was 1, the other output would always be 0 (i.e. complementary outputs), dead-time aside. I'm looking for a Push-Pull configuration. See this post:
https://my.st.com/public/STe2ecommunities/mcu/Lists/cortex_mx_stm32/Flat.aspx?RootFolder=https%3a%2f%2fmy.st.com%2fpublic%2fSTe2ecommunities%2fmcu%2fLists%2fcortex_mx_stm32%2fhow%20to%20generate%20pwm%20for%20push-pull%20converter&FolderCTID=0x01200200770978C69A1141439FE559EB459D7580009C4E14902C3CDE... And this one: http://www.cypress.com/?rID=35431- Mark as New
- Bookmark
- Subscribe
- Mute
- Subscribe to RSS Feed
- Permalink
- Email to a Friend
- Report Inappropriate Content
2011-08-11 3:26 PM
- Mark as New
- Bookmark
- Subscribe
- Mute
- Subscribe to RSS Feed
- Permalink
- Email to a Friend
- Report Inappropriate Content
2011-08-11 11:54 PM
- Mark as New
- Bookmark
- Subscribe
- Mute
- Subscribe to RSS Feed
- Permalink
- Email to a Friend
- Report Inappropriate Content
2011-08-12 1:58 PM
That did the trick. Thanks for your help!
