Current Sources and Voltage References

100

Current scaling

For a 50% increase in gain, this would mean that the gain is now 75, so that:

Considering that the nominal output current with a gain of 50 is 423.7 µA, this equates

to a change in output of –0.22% for a 50% reduction in gain or a +0.035% for a 50%

increase in gain. This is impressive regulation, all created by beta-compensation, but

in practice because of base current errors, their accuracy may be reduced (from that

of a 1:1 circuit) by about 1% to 2%. These circuits will probably work well down to

about 2 volts or above 30 volts, if required.

Those were some examples of multiplying a current, but it’s just as easy to

divide

the ...