Go Down

Topic: Double PWM signals with High frequency (Read 1 time) previous topic - next topic

MarkT

Hi,

Not only are you trying to change the duty cycles. You are also trying to change the width of the signal when it is high and low. I am not sure that PWM can do that.
That's the same thing.  duty cycle controls the width of the high and low parts of the waveform (in concert
of course).

Read the datasheet of the IC if you want to find out what it can do, it can do a lot (there are 16 modes
for timer1, for instance).
[ I will NOT respond to personal messages, I WILL delete them, use the forum please ]

cattledog

Quote
I need to give fire signals to 2 transistors where each signal have the same frequency and duty cycles but shifted around half of the frequency period to each other.
Quote
the interleaved boost converter needs a square pulses each one have the same duty cycle but each one is shifted  about half  of the conduction period like this (check the attachments):
I am uncertain of your requirements given this image you posted

Can you please attach a hand drawn sketch of what you want? Do you want a deadband between the two pulses?

Check out these two threads for non overlapping complementary pulses
https://forum.arduino.cc/index.php?topic=438667.0
https://forum.arduino.cc/index.php?topic=495249.0

johnwasser

The picture shows two pulse trains with DIFFERENT frequency and DIFFERENT duty-cycle.  That is not what is being described.  The descriptions seem to call for two identical PWM signals (SAME frequency and SAME duty cycle) that are 180° out of phase (offset by half the PWM period).  To do that you will need to use TWO timers.  Set them both up to generate the required PWM frequency.  Use the GTTCR (General Timer/Counter Control Register) to start them with the required phase difference.  They will then run at that phase offset and you can change the duty cycle as needed.
Send Bitcoin tips to: 1G2qoGwMRXx8az71DVP1E81jShxtbSh5Hp

Go Up