Voltage-Controlled Linear Current Source

118

01:22:25

Use the 100 ohm resistor to change the voltage scaling (1k = 1mA/V, 100 = 10mA/V, 10 = 100mA/V).

Capacitor added for high frequency stability. Large values result in larger reaction times.

(Load Current) / (Input Voltage)  = (Resistor second from left) / ((Leftmost resistor) * (Bottommost Resistor)).

@hurz since you're a bit of a wizard, how do I determine voltage slew rate of output given the capacitor's capacitance (as a variable) and the current resistors? What would be the optimal capacitance? I'm genuinely curious as to how you would derive it.

published 7 years ago

sahalsawas

7 years ago

thanx

hurz

7 years ago

Upps, there is a question.... slew rate...' hmmm, at least there is no dependency from 100Ohm shunt to the overall max bandwidth. The bandwidth is limited to the first opamp stage here which is an inverting amp with a weak integral cap. 1/(100kOhm x 2*pi x 10pF)=159kHz. For a slew rate you are probably limited to about 10us. Hope this helps.

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