| 摘要 |
PROBLEM TO BE SOLVED: To provide a current measuring circuit with a plurality of ranges that suppresses a waste of arithmetic processing by an arithmetic part and measures a current at a high speed.SOLUTION: A current measuring circuit includes a current measurement range discrimination signal generation part which outputs a current measurement range discrimination signal for discriminating different current measurement ranges; a conversion part having an AD converter which converts an analog input value corresponding to a measured current into a digital output; and an arithmetic part which outputs a sampling control signal for controlling sampling timing of the AD converter, discriminates the current measurement range discrimination signal in synchronism with the timing of output of the sampling control signal, and calculates the measured current on the basis of a plurality of voltage-current characteristic curves such that output voltages for the measured current which are switched based upon the current measurement range discrimination signal are different in gradient for the measured current and the digital output value that the conversion part outputs. |
