Patent ID: 9638724
Date: 2017-05-02
CPC Classifications: G01R

Claim:
1. Current measurement apparatus comprising: a measurement arrangement configured to be disposed in relation to a load which draws a load drawn current signal, the measurement arrangement being operative when so disposed to measure the load drawn current signal; a signal source operative to apply a reference input signal to the measurement arrangement whereby an output signal from the measurement arrangement comprises a load output signal corresponding to the load drawn current signal and a reference output signal corresponding to the reference input signal; and processing apparatus which is operative to receive the output signal and to make a determination in dependence on the reference output signal, in which the signal source comprises a current multiplier which defines first and second current paths, the current multiplier being configured such that: the first path carries a multiplier input current signal; the second path carries a multiplier output current signal which determines the reference input signal and which corresponds to the multiplier input current signal multiplied by a multiplier value determined by the current multiplier; and the multiplier input current signal and the multiplier output current signal are carried on their respective paths in a same direction relative to a power supply voltage, and the signal source is configured such that power drawn through the second path as divided by the multiplier value is less than the power drawn through the first path.