Oki Semiconductor Co., Ltd.

Lapis Semiconductor Co., Ltd.

Oki Electric Industry Co., Ltd.

Shuji Furuichi

Takayuki Shimizu

Naoya Kimura

Tetsuro Hara

Haruyo Takayanagi

Akira Kondo

A level shift circuit includes: a constant-current generation unit; a current mirror unit that flows the constant-current through first and second lines; and a level shift unit that receives first and second input signals, the first input signal being varied between first and second logic levels and having first and second potentials at the first and second logic levels respectively, the second input signal being a phase-inverted signal of the first input signal, the level shift unit producing first and second output signals that are acquired by shifting a signal level at the first logic level of the first and second input signals from the first potential to the power supply potential, the level shift unit outputting the first output signal from a node on the second line and outputting the second output signal from a node on the first line. The constant-current generation unit includes a current adjustment circuit which varies the constant current value depending on a variation in the first potential.

Level shift circuit

A temperature detection circuit that can detect temperature with high accuracy regardless of manufacturing variations, and a method of adjusting the same. The circuit includes: first and second diodes having respective independent p-n junctions; a first current path including a first variable voltage dividing resistor series connected to the first diode; a second current path including a second variable voltage dividing resistor series connected to the second diode; a reference voltage generation part that feeds back a differential voltage to each of the first and second current paths and outputs as a reference voltage the differential voltage indicating a difference between a first divided voltage of the first variable voltage dividing resistor and a potential on the second current path; and a temperature detection signal generation part generating a temperature detection signal based on a second divided voltage of the second variable voltage dividing resistor.

Temperature detection circuit and method of adjusting the same

A display driver circuit for driving a current-controlled light-emitting device to emit light with a luminance gradation includes a memory for storing compensation data based on a measured value of a threshold voltage of a transistor for driving the light-emitting device, a register for holding the data to be displayed, and a data line driver for measuring the threshold voltage of the transistor through a data line connected to the transistor to produce the compensation data and store the compensation data in the memory and correcting the data to be displayed held in the register with the compensation data stored in the memory to output the gradation signal to the data line. Thus, the display driver circuit can be smaller in size than conventional circuitry which has a separate analog-to-digital converter.

Display driver circuit for driving a light-emitting device with the threshold offset of a drive transistor compensated for

A current driver circuit includes a DA conversion part for generating a display current whose magnitude corresponds to a value of a displayed data, a timing control part for generating a write controlling signal, and a plurality of electric current latching parts, each of which generates a driving current. Each of the electric current latching parts having a capacitor generates a display current whose magnitude corresponds to a magnitude of a voltage to which the capacitor is charged. Each of the elective current latching parts performs a reset operation that once discharges the capacitor in response to a reset signal generated by the timing control part. The current driver circuit can generate the driving current with high accuracy and improve the speed of response to the display device.

Current drive circuit for supplying driving current to display panel

The object of the invention is elimination of an occurrence of instantaneous light in the center part of a display, a border between the upper half and the lower half of the display. An scanning method of the display, dividing the display panel to a first filed and a second filed, starts a counter therein, synchronized with the timing of driving a first row electrode of the first filed thereof, and drives a first row electrode of the second filed thereof, every time the counter value changes.

Scanning method of display panel and a display unit

A current driving circuit includes a bias voltage generator that generates a bias voltage and multiple constant current drivers that output driving currents. Each constant current driver includes first and second transistors coupled in series between two power supply potentials, and a third transistor that forms a current mirror with the second transistor. The control terminal of the first transistor receives the bias voltage. The control terminals of the second and third transistors are both connected to the node at which the first and second transistors are interconnected. This circuit configuration makes the output current, which is obtained from the third transistor, comparatively immune to fabrication process variations and variations in power-supply potentials.

Growing community of inventors

Tokyo, Japan

Shuji Furuichi