Patent ID: 7330985

Claim:
A method of changing operating voltages of plural programmable logic circuits when plural unit circuits are operated in a time-sharing manner using the programmable logic circuits, each of the programmable logic circuits having a circuit configuration that is reconfigurable during operation using each of circuit configuration data corresponding to each of the plural unit circuits, the method comprising: assigning each of said plural unit circuits to each of said programmable logic circuits; measuring operation times for each of said plural unit circuits; calculating first total operation times for each of said plural programmable logic circuits, each of the first total operation times corresponding to a sum of said operation times for each of said plural programmable logic circuits; changing assignment of said plural unit circuits using said first total operation times; calculating second total operation times for each of said plural programmable logic circuits, each of the second total operation times corresponding to a sum of said operation times for each of said plural programmable logic circuits according to the changed assignment; finding a frequency of a clock signal supplied to said plural programmable logic circuits using a maximum value of said second total operation times; finding operating voltages of said plural programmable logic circuits using said clock frequency; and changing the operating voltage of each of the programmable logic circuits and the frequency of the clock signal to the found operating voltage and the found frequency, respectively.