how to get 50 % duty cycle with complementry pulse

[Ranjeet Singh]

i want to generate 50 % duty cycle at freuency (100khz-200 KHz), but i am not getting 50% , i am getting 33-34% duty cycle.this duty cycle change when the frequency change.

[Tesla DeLorean]

Show the functions initializing the timer.

Is the frequency as expected?

ARR = N - 1

CCR1 = N / 2

​

F​rom the scope screen it's hard to see the cycles, or if they are complementary.

​

Show all registers in TIM1

[Ranjeet Singh]

YES ,Frequency is same as expected

[Ranjeet Singh]

[Ranjeet Singh]

ARR = N - 1

CCR1 = N / 2

for this parameter

ARR = 150-1

CCR1 = 150/ 2

[Ranjeet Singh]

[Ranjeet Singh]

i am using the stm32 g0b1re Microcontroller Board

[Ranjeet Singh]

if i will use the same parametere at 1KHz frequency then i will got the 50% duty cycle.

time clock -64Mhz

prescale-64-1.

so i will get frequency 64/64= 1 Mhz.

and using ARR value = 100

frequency =1M/100= 10 KHz

CRR=50

duty cycle= (50*100)/100= 50 % duty

but when

prescale-1.

and using ARR value = 100

frequency = 317KHz

CRR=50

duty cycle= 25 % duty

using crr =50 and arr 100 why not duty cycle become 50n%?

[Ranjeet Singh]

what i m doing wrong ?

[AScha.3]

not wrong, but maybe there is some deadtime active.

timer -> complementary outputs = usually need deadtime .

try setting it very short.

+ set timerclk 64M , no prescaler.

for 10khz out -> arr 6400 , 300khz out -> 210 .

[Ranjeet Singh]

yes ,thank you ,its done i have got 50 %

[AScha.3]

Great!

When your question is answered, please mark this topic as answered by choosing Select as Best for the preferred answer, as also explained here. This will help other users find that answer faster.

[Ranjeet Singh]

i am using frequency (211Khz to 103Khz ) for inverter mosfet (STF24N60M2) FOR 1.2kw eV Chareger. in this project my duty cycle not maintain at 50% because i am using deadband .i want to maintain duty cycle same as it is for 211KHz same for 103Khz ,what minimum value of deadband i can putt ?,so that duty cycel will same and do not get short MOsfet ( deadband mandatory for mosfet EV circuit )