PWM frequency multiplier circuit questions

I’m in need of multiplying a 1khz pwm frequency up to near 20khz frequency without losing significant resolution.

This is an automotive application… I have a pwm output from the cars ecu at 78hz that I need to multiply up to around 15khz which I then will input into an existing pwm controller consisting of a driver and mosfet circuit that powers a DC water pump at a variable speed based on the output from the cars ecu.

I’ve found a ready made solution from jbperf.comhttp://jbperf.com/pwm_converter/index.html … But it’s no longer available. That solution takes a custom programmed 8pin chip, and with jumpers multiplies the frequency by a factor of 2,4,8,16,32,64,128 or 256. Keeping a resolution of 0.25%

From my reading on the subject it seems to be a phase locked loop circuit but I’ve been unable to find any components that will work with an input below 1khz.

I have no problem building the circuit on proto board if I can find that 8 pin chip.

I would use the info @ the bottom of their page: "You can contact me through PM at the msextra forum where my user name is racingmini_mtl

or by email: boards at jbperf.com" and see if they have a different solution nowadays