OPERATING SPEED DECIDING SYSTEM FOR INFORMATION PROCESSOR

摘要

PURPOSE:To always set an operating speed in accordance with the environment of a working power supply by providing a frequency selection circuit which selects an operating speed according to the type of the power supply. CONSTITUTION:A frequency selection circuit which selects and decides an operating frequency consists of a dividing circuit 5 which generates a low speed clock signal 8 and a high speed clock signal 9 by dividing a basic clock signal 7 and a selector circuit 4 which selects the signal 8 or 9 with reception of a power voltage deciding signal 11. When an AC is inputted to a power supply 1, the signal 11 has a high level end an operating clock signal 10 has the same frequency as the signal 9. Meanwhile the signal 11 has a low level and the signal 10 has the same frequency as the signal 8 with a battery power supply 15.