PURPOSE: To reduce power consumption and to stabilize a voltage comparing circuit by cutting off a current flowing through the voltage comparing circuit in a stop period and holding the floating state of the internal potential of the circuit at a constant potential.
CONSTITUTION: When a signal VIN is applied to an input terminal 9 and signals Vc and Vc' are applied to control input terminals 11 and 12, an MOS transistor (TR)15 turns on and TRs Q18 and Q21 turn off during a period other than a stop period TB, so a waveform-shaped signal VOUT in phase with the input signal appears at an output terminal 10. During the stop period TB, on the other hand, the TRQ15 turns off, so currents flowing through the TRs Q16 and Q17 are intercepted. At this time, the TRQ18 turns on, so the gate of a TRQ14 is held fixedly at a low level, turning off the TRQ14. Further, the TRQ21 turns on, holding the output terminal fixedly at a high level. Thus, the floating states of the MOSTRs to stabilize the circuit.
SAKATA NOBORU
IKEDA MIYUKI
HIRACHI KAZUHARU
SUZUKI YOSHINORI
HITACHI MICROCUMPUTER ENG