how to modulate current in pwm square waves as per the requirement

[milner]

Hi,..My device generated PWM square waves. I can program the frequencies and delays that is desired. but how to modulate current as per our requirement. I need the current range of 50 - 500 uA 

[Rune Holmgren]

PWM will allow you to modulate the voltage and this is typically what you are trying to control. The current is determined by the resistance and the voltage, so (simplified a bit) if you know the resistance you can use Ohm's law to calculate the necessary voltage.

Best regards,
Rune Holmgren