Panasonic Corporation

Shinichiro Kataoka

Yasunori Yamamoto

Daisuke Itou

Go Takata

Tsukasa Kawahara

Ryuji Ueda

Takehiro Yano

Short circuit failures and open circuit failures of light-emitting elements used for the backlight in an LCD panel can be reliably and easily detected. The voltage at the node between each series-connected light-emitting element array and a drive circuit is detected as a monitored voltage. A maximum detector detects the highest and a minimum detector detects the lowest of these monitored voltages. Short circuit or open circuit failure of a light-emitting element is detected by comparing the voltage difference between the maximum detector output and the minimum detector output with a specific reference voltage.

Light-emitting element driving device

The load driving apparatus according to the present invention includes a load current setting signal generating section, a load current generating section, a reference voltage generating section and a drive voltage generating section. The load current setting signal generating section generates a desired load current setting signal. The load current generating section generates a load current based on the load current setting signal to drive the load. The reference voltage generating section generates a reference voltage based on the load current setting signal. The drive voltage generating section generates a drive voltage, supplies the drive voltage to the load, generates a between-both-terminals voltage between both terminals of the load current generating section based on the drive voltage and controls the drive voltage so that the difference between the between-both-terminals voltage and the reference voltage becomes small.

Load driving apparatus

A semiconductor device which can achieve high breakdown voltage and high ESD tolerance of a current drive output terminal at the same time, and can quicken the response speed of a current flowing through the current drive output terminal. The inventive semiconductor device is provided, between the current drive output terminal and a first transistor or a low breakdown voltage element, with a second transistor having a breakdown voltage higher than that of the first transistor or that of the low breakdown voltage element. Furthermore, the inventive semiconductor device is provided with a diode having an anode connected with a path between the first transistor or the low breakdown voltage element and the second transistor, and a cathode connected with an ESD protection circuit.

Semiconductor device

A semiconductor device of the present invention includes: a power input terminal; an internal power supply circuit that converts a voltage supplied from the outside to the power input terminal into a predetermined voltage; an analog circuit connected to an output side of the internal power supply circuit; an internal power output terminal connected to the output side of the internal power supply circuit; a logic circuit power input terminal; a logic circuit connected to the logic circuit power input terminal; and interterminal wiring connecting the internal power output terminal to the logic circuit power input terminal. The internal power supply circuit has a configuration of supplying power to the analog circuit and the logic circuit, and in a package assembly (finished product), a resting current in the logic circuit can be inspected without being influence by a consumption current in the analog circuit.

Semiconductor device and method for inspecting the same

Of a pair of switching transistors connected in series between a high voltage power source and the ground, when the switching transistor on the high potential side is controlled by an RS flip-flop in response to an input signal, in order to prevent a malfunction caused by the influence of dv/dt transient phenomena of an output terminal for driving a load, a latch circuit is reset using an input signal from a low side input terminal LIN in a period during which the voltage of the output terminal for driving the load abruptly decreases.

Switching transistor driver circuit controlling power supply to the load

A semiconductor device includes a phase compensation circuitusing a MOS capacitor with a structure in which an insulating film is disposed between a gate electrode formed on a semiconductor substrate and a diffusion layer. The phase compensation circuit includes first and second MOS capacitors. A gate electrode terminal of the first MOS capacitor is connected equivalently to a diffusion layer terminal of the second MOS capacitor that is a terminal opposite to the gate electrode terminal. A potential difference generating elementthat generates a potential difference by allowing a current to flow therethrough is connected between a diffusion layer terminal of the first MOS capacitor and a gate electrode terminal of the second MOS capacitor. When the MOS capacitors having the voltage dependence are used, e.g., as a phase compensation circuit element of an operational amplifier, the MOS capacitance is not reduced, no matter the range of the input or output voltage of the operational amplifier, so that the phase margin will not reduced.

In a standby mode, a voltage step up DC/DC convertersupplies a power output voltage equal to or higher than a second set voltage which is lower than a first set voltage in a normal operating mode to a microcomputer (load)with current supply performance which is smaller than in the normal operating mode. On the other hand, in the normal operating mode, a voltage step up/step down DC/DC convertersupplies the first set voltage in the normal operating mode to the microcomputer

Growing community of inventors

Osaka, Japan

Shinichiro Kataoka