Patent ID: 7405611
Filing Date: 2008-07-29
Classification: H03K

Abstract:
1. A semiconductor integrated circuit device comprising a semiconductor integrated circuit including a MOS transistor having a substrate and a source, wherein a substrate supply voltage and a source supply voltage are separately provided to the MOS transistor, wherein the substrate is connected to two substrate supply voltage generating units, and the two substrate supply voltage generating units are switched by a control signal; wherein: at least one of the substrate voltage supply generating units comprises a monitor element including a monitor MOS transistor, a current source, a comparator, and an amplifier configured to receive an output from the comparator and output the substrate supply voltage applied to said MOS transistor in the semiconductor integrated circuit, a drain of the monitor MOS transistor of the monitor element is connected to the current source; the comparator is configured to compare a drain voltage of the monitor MOS transistor with a signal indicative of a leak current of the MOS transistor in the semiconductor integrated circuit; a substrate voltage of the amplifier is adjusted such that a drain voltage of the MOS transistor in the semiconductor integrated circuit is equal to the substrate supply voltage supplied to the semiconductor integrated circuit; and a gate voltage of the monitor MOS transistor of the monitor element is controlled by the control signal.