I want to use a small PWM driver PCB (that I hacked from a RC vibrator sex toy) to drive three other motors using a single 3.7V lithium-ion battery. (The motors are rated 3V.)
The PWM driver originally ran off 2xAAA batteries and drove a small motor connected between the + and the PCB output.
I replaced the original motor with an LED purely to indicate the state of the PWM, it will be removed from the circuit once working.
The three other motors draw about 900mA when connected directly to the 3.7V battery (no PWM) and I am afraid it will be too much for the original PCB to handle over a long period.
I tried to use a MOSFET to switch the higher load from the PWM driver, but I can't get it to switch on high enough to drive even a single motor. I can get it to flash an LED between the drain and +V, but as soon as I connect even a single motor it stops.
I have tried with IRF540N and NDP6020 (lower RDS), but neither seem to do the trick.
Can anyone make a suggestion?