Hello I am trying to make a PWM Controller Current Source to gain 0-0.7mA using the scheme below. Can I use the pwm as the Vcc regardless pwm.can only supply 0.2 mA at max. If can't, are there any alternative for this?
Getting a circuit to produce current gain REQUIRES a source of power that can supply the required current. If that were not the case you could make a perpetual motion machine and there would be unlimited free energy. These things are just not possible.
What you need is s low pass filter to covert the PWM signal into voltage followed by a voltage controlled constant source. It needs to be powered by an external source.