Patent ID: 6194952
Filing Date: 2001-02-27
Classification: H03K

Abstract:
A transmission gate circuit, comprising:a switch configured to switch between a power supply voltage, a ground potential and an open terminal potential to a power supply terminal of the transmission gate circuit;a first p-channel MOS transistor having first and second terminals respectively connected between input and output terminals of the transmission gate circuit, and having a gate configured to receive a first control signal;a second p-channel MOS transistor having first and second terminals respectively connected to a source and back gate of said first p-channel MOS transistor, and configured to receive the first control signal at a gate thereof for short-circuiting the source and back gate of the first p-channel MOS transistor when the power supply voltage is supplied to the power supply terminal and said first p-channel MOS transistor is turned conductive; anda third p-channel MOS transistor configured to connect the power supply terminal via a first node and having one terminal connected to the back gate of said first p-channel MOS transistor, the other terminal and back gate connected to the first node, and a gate configured to receive a second control signal to connect the back gate of said first p-channel MOS transistor to the power supply terminal when the power supply voltage is supplied to the power supply terminal and said first transistor is turned non-conductive;a diode having a cathode connected to the first node and an anode connected to the power supply terminal;a first control circuit connected to the first node, and configured to receive a third control signal and to output a potential of one of 1) the first node and 2) the ground potential as the first control signal in accordance with a switching state of said switch; anda second control circuit connected to one of 1) the first node and 2) the power supply terminal, and configured to output one of 1) the potential of the first node or the potential of the power supply terminal and 2) the ground potential, as the second control signal in accordance with the first control signal.