Method and circuit for determining the power consumption requirements for a semiconductor logic circuit and designing the circuit accordingly

A logic circuit determines the power consumption of a semiconductor integrated device by taking into consideration the variation of the rate of operation. A control signal (TEST) is applied to each control signal input port (Tin) of flip-flop circuits of flip-flop circuit groups and a logic gate circuit having a plurality of input ports A and B in a combined circuit group. If the control signal (TEST) is low, both the flip-flop circuits and the logic gate circuit operate normally. However, if the control signal (TEST) is high, each of them performs the power consumption test. Regardless of the value of input signals applied to input ports D1 and D2 of the flip-flop circuits, the flip-flop circuits are controlled to have a repetitive output signal of high and low levels at ports Q1 and Q2, in synchronism with a clock signal. Through this operation test, operational failure is reduced and the quality of semiconductor chip production is guaranteed, because it is possible to predict accurately the power consumption when designing the logic circuit due to the relationship between the rate of operation and the power consumption.