Matsushita Electric Industrial Co., Ltd.

Panasonic Corporation

Tetsuro Oomori

Yasuyuki Doi

Kazuyoshi Nishi

Hiroshi Kojima

Makoto Mizuki

Hisao Kunitani

Noriko Kaku

The current drive device of the present invention includes: a current source transistor for allowing a preset drive current to flow to a drain; a cascode transistor cascode-connected to the current source transistor; a switch circuit for switching ON/OFF flow of the drive current through the drain of the cascode transistor and a circuit to be driven; and a bypass circuit for allowing the drive current to flow therethrough to bypass the switch circuit and the circuit to be driven when the switch circuit is OFF.

Current drive device

A source driverA arranged on a liquid crystal panel includes therein in-chip reference voltage wiresextending from one end to the other end of an LSI chip. The source driverA includes therein: branch reference voltage wiresbranching off from in-chip reference voltage wires; reference voltage production buffers; a control circuitfor controlling the reference voltage production buffers; a reference voltage production resistor sectionfor subdividing the reference voltage into values of n steps; voltage level selection circuitseach for selecting one of the subdivided voltages; and output buffers. Since the reference voltages are supplied to each source drivervia wiring for connecting the in-chip reference voltage wiresin series with one another, the wiring structure for supplying the reference voltages can be simplified.

Display panel including a plurality of drivers having common wires each for providing reference voltage

Liquid crystal driving circuit, semiconductor integrated circuit device, reference voltage buffering circuit, and method for controlling the same

It is an object of the present invention to provide a high slew rate differential amplifier circuit that can reduce current consumption while maintaining stability. A P-type MOS sub-current source ( ) having a current source circuit including a transistor (M ) having a gate voltage of a P-type MOS output transistor (M ) input to a gate thereof and a constant current source transistor (M ) connected in series with the transistor (M ), the current source circuit being connected in parallel with a constant current source transistor (M ) of a P-type MOS differential input section ( ) is combined with an N-type MOS sub-current source ( ) including a current source circuit including a transistor (M ) having a gate voltage of an N-type MOS output transistor (M ) input to a gate thereof and a constant current source transistor (M ) connected in series with the transistor (M ), the current source circuit being connected in parallel with a constant current source transistor (M ) of an N-type MOS differential input section ( ). To increase a current through the differential input section when a high slew rate is required, the current source circuit including the transistor having the gate voltage of the output transistor input to the gate thereof and the constant current source transistor connected in series with the first transistor is used as a sub-current source for a differential circuit, in order to reduce a steady-state current.

High slew rate differential amplifier circuit

Growing community of inventors

Hirakata, Japan

Tetsuro Oomori