Abstract: A semiconductor device is capable of suppressing variations of a current or a voltage to be supplied to an external circuit. The semiconductor device has a plurality of unit areas arrayed in one direction, and components in the unit areas are arranged in the same shape and the same layout in the unit areas. A holding capacitor for holding a voltage is surrounded by an interconnect kept at ground potential. Interconnects at ground potential are inserted in areas where reference current interconnects for supplying reference currents to functional blocks (1-bit DCC circuit regions) and gradation digital data interconnects and storage timing signal interconnects cross each other vertically, the interconnects being disposed between these reference current interconnects, gradation digital data interconnects and storage timing signal interconnects.

Abstract: An object of the present invention is to provide a display device for making it possible to accurately adjust a gradation current even if there is a variation in characteristics of a transistor for driving an organic EL element in a display device using an organic EL element. The following are included: a current detecting circuit for detecting a current circulating through a light emitting element, a current adjustment control circuit for comparing the detected current value with a reference current value and adjusting a current to be supplied to the light emitting element of a display portion in accordance with the comparison result, and a reference current circuit for generating a reference current correspondingly to the adjusted current. Moreover, a reference current circuit is formed on the substrate same as the substrate on which a light emitting element of a display portion is formed.

Abstract: A display device is comprised of a data line driver, a scan line driver, and a display panel. The display panel is composed of a plurality of drive legs disposed between a current output node and a first node having a fixed potential, each of the drive legs including a drive transistor having a source connected to the first node, a capacitor connected between a gate of the drive transistor and a second node having a fixed potential, a first switch connected between the current output node and a drain of the drive transistor, and a second switch connected between the gate and the drain of the drive transistor. The display panel further includes a data line, a third switch connected between the current output node and the data line, a current-driven element, a fourth switch connected between the current output node and the current-driven element.

Abstract: A current source circuit includes a voltage output section which outputs a voltage signal; a current source section and a conversion section. The current source section has at least one current source block comprising a plurality of current sources, each of which outputs an output current. The conversion section is provided between the voltage output section and the current source section and outputs a reference current to the plurality of current sources of the at least one current source block based on the voltage signal such that the output current from each of the plurality of current sources is set based on the reference current.

Abstract: A drive circuit drives a display device including a plurality of pixels arranged as a matrix. Luminous elements are provided for the individual pixels. In this circuit, the luminous element and a drive transistor for driving the luminous element in each of the pixels are serially connected between a first power supply and a second power supply. A first switching transistor supplies the gate of the drive transistor with a control signal for controlling the drive transistor. A differential amplifier compares a voltage at a connection point between the luminous element and the drive transistor, and a control voltage which is input in the differential amplifier so as to control the luminance of the pixel, thereby generating a control signal. The control signal is supplied to the gate of the drive transistor via the first switching transistor. A hold capacitor holds a voltage between the gate and the source of the drive transistor.

Abstract: A drive circuit drives a display device including a plurality of pixels arranged as a matrix. Luminous elements are provided for the individual pixels. In this circuit, the luminous element and a drive transistor for driving the luminous element in each of the pixels are serially connected between a first power supply and a second power supply. A first switching transistor supplies the gate of the drive transistor with a control signal for controlling the drive transistor. A differential amplifier compares a voltage at a connection point between the luminous element and the drive transistor, and a control voltage which is input in the differential amplifier so as to control the luminance of the pixel, thereby generating a control signal. The control signal is supplied to the gate of the drive transistor via the first switching transistor. A hold capacitor holds a voltage between the gate and the source of the drive transistor.

Abstract: A head tracking system for a magnetic head includes a servo signal generator for generating a position error signal, a low-pass filter passing the position error signal, an A/D converter converting the position error signal into a digital position error signal, a signal processor for generating a total error signal based on the digital position error signal and the distance between the present track and the target track, and an actuator moving the magnetic head to the target track based on the total position error signal. The low-pass filter has a cut-off frequency equal to one-half the sampling frequency of the A/D converter. If the frequency of the position error signal is high, the output of the servo signal is supplied by a selector directly to the A/D converter thereby bypassing the low-pass filter. Alternatively, the cut-off frequency of the low-pass filter is controlled based on the frequency of the position error signal.