Semiconductor integrated circuit, liquid crystal drive device, and liquid crystal display system

1. A semiconductor integrated circuit comprising:

an input circuit for receiving a pair of differential signals input from outside of the semiconductor integrated circuit device and supplying an output signal according to a voltage difference between the differential signals;

an internal logic circuit for receiving the output signal from the input circuit and performing logic operation; and

an output circuit for outputting a signal having an amplitude larger than that of a signal of the internal logic circuit to the outside of the semiconductor integrated circuit device,

wherein the input circuit comprises:

a differential amplification stage for amplifying a differential input signal, the differential amplification stage having:

a pair of differential MOS transistors having a common source;

a MOS transistor for current coupled between the common source of the pair of differential MOS transistors and a power supply voltage terminal; and

an output stage for generating the output signal based on a voltage output from the differential amplification stage,

wherein a first power supply voltage is supplied to the internal logic circuit and a second power supply voltage higher than the first power supply voltage is supplied to the differential amplification stage of the input circuit and to the output circuit.

2. The semiconductor integrated circuit according to claim 1 ,

wherein the semiconductor integrated circuit is a liquid crystal drive device in which a digital data signal of each pixel as a differential signal is input to the input circuit and a drive voltage for driving a liquid crystal panel is output from the output circuit based on the digital data signal, and wherein the power supply voltage for driving the liquid crystal panel is used as the second power supply voltage,

wherein the second power supply voltage is supplied to the differential amplification stage of the input circuit, the output circuit, and the liquid crystal panel.

3. The semiconductor integrated circuit according to claim 1 ,

wherein the MOS transistor for current is a first P-channel MOS transistor having a gate to which a bias voltage is applied, a source coupled to the power supply voltage terminal, and a drain coupled to the common source.

4. The semiconductor integrated circuit according to claim 3 ,

wherein the pair of differential MOS transistors comprises a pair of second P-channel MOS transistors whose gates receive the pair of differential signals, a source terminal of each said second P-channel MOS transistor is coupled to the common source.

5. A liquid crystal display system comprising:

a liquid crystal drive device which has a differential input circuit including a differential amplification stage for receiving a differential signal and an output stage for generating an output signal based on of an output of the differential amplification stage, which receives display data via the differential input circuit and generates a liquid crystal drive output based on the display data, and to which a liquid crystal driving voltage larger than an operation voltage supplied to the output stage is supplied as an operation voltage of the differential amplification stage;

a liquid crystal panel for performing display based on the liquid crystal drive output of the liquid crystal drive device; and

a controller for outputting display data and a signal for operation control to the liquid crystal drive device,

wherein the liquid crystal driving voltage which is larger than the operation voltage of the output stage is supplied to the differential amplification stage of the differential input circuit and the liquid crystal panel.