yet another problem with analog circuitry:
I want to make a voltage-controllable current source "abusing" a buck controller. The basic Idea is using a simple controller, that takes an analog voltage as a control input(for example 0-5V). This voltage sets the desired output current.
I was looking at some buck controllers that use a pwm signal to set the output voltage. They take a feedback voltage to control the output voltage of the buck converter. I was thinking of using a current sense resistor to convert the output current into a feedback-voltage. I have an inductive load (motor coil), so the pwm-voltage at the output (amplified with a mosfet) will give me a (low ripple) dc-current.
Now the question: which controller could be used? I am looking for a simple, cheap one, but still not needing too many external components.
The frequency of the pwm is still to be determined, i suppose 200-500kHz will do. any suggestions?
Or: do you have a suggestion for a completely different approach? What I have is an analog control voltage and what I need is a proportional current through a motor coil. The current has to be the same for different motors connected to the output. I'm talking about 200mA at most.
I want to make a voltage-controllable current source "abusing" a buck controller. The basic Idea is using a simple controller, that takes an analog voltage as a control input(for example 0-5V). This voltage sets the desired output current.
I was looking at some buck controllers that use a pwm signal to set the output voltage. They take a feedback voltage to control the output voltage of the buck converter. I was thinking of using a current sense resistor to convert the output current into a feedback-voltage. I have an inductive load (motor coil), so the pwm-voltage at the output (amplified with a mosfet) will give me a (low ripple) dc-current.
Now the question: which controller could be used? I am looking for a simple, cheap one, but still not needing too many external components.
The frequency of the pwm is still to be determined, i suppose 200-500kHz will do. any suggestions?
Or: do you have a suggestion for a completely different approach? What I have is an analog control voltage and what I need is a proportional current through a motor coil. The current has to be the same for different motors connected to the output. I'm talking about 200mA at most.