Voltage supply circuit and control method of the same

Abstract

A voltage supply circuit capable of dealing with an abrupt change of a load by controlling an amount of increase of a power source voltage to be larger than an amount of reduction, supplying a stable operating power source voltage, and realizing lower power consumption while maintaining normal operation of a semiconductor integrated circuit is provided. By providing a replica circuit , detecting a delay time of a critical path of an LSI , comparing a delay time detected by a control circuit with a predetermined reference value, performing control to raise a voltage V supplied to the LSI when the delay time is larger than the reference value as a result of the comparison and to lower the voltage V supplied to the LSI when the delay time is smaller than the reference value, and making the amount of increase at the time of raising the supplied voltage larger than the amount of reduction at the time of lowering it, when the supplied voltage V becomes smaller than the reference value, it can be quickly restored to be larger than the reference value, the time when operating error of the LSI may occur can be greatly shortened, and the operational stability of the voltage supply circuit can be improved.