Rohm Co., Ltd.

Takahiro Ota

Isao Yamamoto

Koichi Inoue

Koichi Miyanaga

Seiichi Yamamoto

Tomoyuki Ito

Eiji Nakagawa

Michiaki Yama

A load driving device according to the present invention includes: a first current generation section generating a first current in accordance with a driving current of a load; a second current generation section generating a predetermined second current; an integration section charging and discharging a capacitor in accordance with magnitude relation between the first current and the second current; a comparison section comparing a terminal voltage of the capacitor and a predetermined threshold voltage; and an output section generating a protection signal based on output logic of the comparison section. Such configuration permits appropriately preventing load burnout.

Load driving device and electrical device using the same

A power supply apparatus connected via a bus line to another power supply apparatus includes a voltage generation circuit generating a voltage, an abnormality detection circuit detecting an abnormality of the power supply apparatus including the abnormality detection circuit and outputting an abnormality detection signal, an abnormality control circuit, and an interface circuit receiving the abnormality detection signal from the abnormality detection circuit to output the signal via the bus line to another power supply apparatus, and receiving the abnormality detection signal via the bus line from another power supply apparatus to output the signal, to the abnormality control circuit and the abnormality control circuit controlling the voltage generation circuit to stop generation of the voltage in a case where receiving the abnormality detection signal from the abnormality detection circuit or in a case where receiving the abnormality detection signal from the interface circuit.

Power supply apparatus and power supply system including the same addressing abnormality

An electronic flash light is emitted from a camera by causing light-emitting diodes corresponding to red, green and blue simultaneously. Light emission of the light-emitting diodes corresponding to respective colors is controlled in accordance with the light-receiving characteristics of the light-receiving elements. For example, by adjusting the on and off duration ratio of switches in accordance with the light-receiving characteristics, the quantity of light emitted by the light-emitting diodes is adjusted.

Image pickup apparatus with light emission control adapted for light-receiving characteristics

An LCD panel module includes a common boosting converter, an LCD boosting circuit, an LDO control circuit, and constant current circuits for parallel-connected LED elements and series-connected LED elements. The LCD panel module is so configured that a type-switching unit can switch over between Typein which the LED elements are connected in parallel and Typein which the LED elements are connected in series. The common boosting converter preliminarily boosts a battery voltage supplied from a lithium ion battery to a low voltage or a high voltage and supplies the boosted voltage to the parallel-connected LED elements or series-connected LED elements respectively. The LCD boosting circuit boosts the low voltage and supplies it to an LCD panel, while the LDO control circuit steps down the high voltage and supplies it to the LCD panel.

Power supply apparatus

A stabilized voltage supply has a semiconductor and an output transistor formed on the semiconductor substrate and responsive to a power voltage. When the power voltage decreases to a level equal to or lower than a predetermined level, the output transistor is saturated. At this time, the semiconductor substrate is heated. The stabilized voltage supply also has a voltage dividing resistor for converting the output current of the output transistor into a stabilized output voltage which in turn is divided to form a feedback voltage. The stabilized voltage supply further has a differential amplifier for amplifying a differential voltage between the feedback voltage and a predetermined reference voltage, the differential voltage being then applied to the control electrode of the output transistor. The control electrode of the output transistor receives a current corresponding to the current applied thereto. The stabilized voltage supply further has a voltage detecting circuit for detecting when the power voltage decreases to a level equal to or lower than the predetermined level, and a current feedback circuit for dividing the output current of the output transistor and for subtracting a current corresponding to the divided current from the current at the control electrode of the output transistor when the power voltage decreases to a level equal to or lower than the predetermined level.

Growing community of inventors

Kyoto, Japan

Takahiro Ota