Increasing PWM duration

Dear All,

I have such little understanding of electronics that I thought it would be better to ask for your help rather than trying to teach myself.

My enquiry will be childs play for you guys, so here goes:-

I have a motorcycle with a heated seat(< 1 amp) which is powered by 12v PWM which has 4 settings

of say 5% - 10% - 25% - 50%, controllable from the handlebars.

I would like to use the seat PWM supply to power a heated jacket (12v, 5 amp) which currently has a PWM controller outputting 50% - 75% - 100%. (BTW 100% gets far too hot)

The challenge therefore is to control a MOSFET or SSR to avoid overloading the seat supply, but to increase the PWM duration by a factor by 1.8.

Being fitted on a motorcycle, it would also need to be compact and durable.

All suggestions will be gratefully received.


Many thanks


What is the frequency of PWM? Do you have any idea?

  Joined February 12, 2018      696
Monday at 02:11 PM

The frequency is approximately 1Hz. 

I have wondered since whether increasing the pulse duration by say 1/3 - 1/2 second could be simply achieved using a 555 timer etc.

many thanks

  Joined March 04, 2021      1
Thursday at 07:03 PM

Are you sure the frequency is 1 Hz? I highly doubtful. However, in such case you could use the 555 that could be useful.

  Joined February 12, 2018      696
Monday at 02:11 PM