Rohm Co., Ltd.

Akinobu Sawada

Masahide Tanaka

Satoru Nate

Natsuki Yamamoto

Mitsunori Nagashima

Kotaro Shibata

Takeshi Sumitani

Hidekazu Kikuchi

Kenichi Niiyama

Koji Taniuchi

Masahiro Muranaka

Daqu Ye

Guanggang Yu

The present disclosure provides a buck converter for achieving a high output and reducing cost. The buck converter includes: a MOSFET, including a first side connected to an application end of an input voltage; a rectifying element, connected to a second side of the MOSFET by a first connection node; a coil, having a first terminal connected to the first connection node; and an output capacitor, connected to a second terminal of the coil. The MOSFET is a super-junction MOSFET.

Buck converter having super-junction MOSFET

A zero-crossing detection circuit includes a logic unit and an input stop detection unit. The logic unit is configured to estimate a zero cross of an AC signal in accordance with at least one of a first monitoring target signal and a second monitoring target signal, respectively input through diodes from a first node and a second node between which the AC signal is applied, so as to generate a zero-crossing detection signal. The input stop detection unit is configured to compare the first monitoring target signal with the second monitoring target signal after giving an offset to one of them so as to generate an input stop detection signal. The logic unit is configured to fix a logic level of the zero-crossing detection signal in accordance with the input stop detection signal.

Zero-crossing detection circuit

A zero-crossing detection circuit includes a zero-crossing detection unit arranged to compare a first monitoring target signal and a second monitoring target signal respectively input through diodes from a first node and a second node between which an AC signal is applied, so as to generate a first comparison signal, and a logic unit arranged to estimate a zero cross of the AC signal from the first comparison signal so as to generate a zero-crossing detection signal. The zero-crossing detection circuit preferably includes a monitoring unit arranged to adjust the first monitoring target signal and the second monitoring target signal to be suitable for input to the zero-crossing detection unit. The logic unit preferably counts a period of the first comparison signal and estimates a zero cross of the AC signal using a count value thereof.

There is provided a configuration of a switching control circuit for use with a switching power supply which generates an output voltage from an input voltage, the switching control circuit having an intermittent operation mode where an operation period in which a switching element of the switching power supply is switched and a pause period in which the switching element is not switched are repeated. The switching control circuit includes a prohibition part configured to prohibit starting a next operation period until a predetermined period of time elapses from a time that a current operation period starts, in the intermittent operation mode.

Switching control circuit, switching power supply, and electric apparatus

A dimming circuit (A) incorporated in a light-emitting-load driving device includes a pre-comparator (CMP) arranged to compare a dimming signal (S) with a threshold voltage (VthCMP) lower than an input buffer (A) of a dimming microcomputer (A) so as to generate a comparison signal (S), and to transmit the comparison signal (S) instead of the dimming signal (S) to the dimming microcomputer (A).

Light-emitting-load driving device and illumination-light source device using same

A lighting apparatus of the present invention includes: a light source; a power source unit arranged to power the light source; a detector unit arranged to detect the deterioration of ability of the power source unit to power the light source; and a determination unit arranged to determine the life of the power source unit in response to the detector unit.

Lighting apparatus

Disclosed is an electric power system including a first unit (for example, a unit) equipped with a first power source (for example, a solar panel ()), a first rechargeable battery (for example, a unit storage battery ()) to which an output of the first power source is input, and a first power consuming portion (not shown) to which an output of the first rechargeable battery is input; a second rechargeable battery (for example, a shared storage battery ()); and an electric power line (for example, a shared electric power line ()) for sharing electric power between the first rechargeable battery and the second rechargeable battery.

Power system

An LED power supply device disclosed in the present specification includes a DC dimmer circuit that performs dimming control of an LED such that the higher a reference voltage variably controlled according to a dimmer signal is, the smaller a current flowing in the LED is. This configuration makes it possible to achieve fine dimming control.

LED power supply device

The switching current control circuit includes a switching pulse supply circuit, a comparator circuit, and analog circuit unit, a digital circuit unit, etc. The A/D converter () detects a load current in an ON period of a switching pulse as a detected current, and converts it into digital data. The arithmetic control circuit () calculates a lower limit of the detected current for providing a timing of switching from OFF to ON of the switching pulse, based on the converted data. Continuation/discontinuous modes are determined whether the lower limit is equal to or greater than 0.

Switching current control circuit, LED dimmer system, and LED illumination device

A light emitter driving device has a decoder portion which monitors a rectified voltage and generates a dimming signal, and a drive current control portion which controls a drive current to a light emitter according to the dimming signal. The decoder portion has a comparator which compares the rectified voltage with a predetermined threshold voltage to generate a comparison signal, a sampling counter which measures high-level and low-level periods of the comparison signal, a duty calculation portion which calculates the duty of the rectified voltage based on the output of the sampling counter, a filter calculation portion which excludes sporadic variation in duty by applying digital filtering to the output of the duty calculation portion, and a dimming signal generation portion which generates the dimming signal based on the output of the filter calculation portion.

Light emitter driving device and lighting appliance therewith

A lighting system has a solar power generation section, a control section which generates a control signal based on the output of the solar power generation section, a power conversion section which converts a direct-current electric power input thereto to output a direct-current electric power, and a lighting section which is driven by the direct-current electric power output from the power conversion section.

Lighting system including power conversion using a control signal based on illuminance information from a solar power generator

The light emitting device control circuit devicein accordance with the disclosure includes a power source V, a transistor TR, a light emitting unit EU, switches Sto S, constant current sources CCto CC, and a controller. A switching voltage Vsis supplied from the controllerto turn ON or turn OFF the transistor TR intermittently, a pulse voltage is supplied to a pulse voltage supplying line Yconnected to a drain terminal D of the transistor TR. The driving signals SPto SPare sequentially supplied to the switches Sto Sto turn ON or turn OFF them (i.e., time division drive). The light emitting devices Ato Aare driven sequentially by a pulse current (i.e., time division drive) when a high voltage is supplied to the pulse voltage supplying line Yand when the driving signals SPto SPare turned ON.

Light emitting device control circuit device and control method of the control circuit device

A lighting apparatus includes an illuminance sensor, a dimming control device and a light source. The lighting apparatus calculates a light output characteristic of the light source based on an illuminance measurement value when the light source is turned off and an illuminance measurement value when the light source is lit with a predetermined output, and calculates an ambient illuminance based on the light output characteristic. The illuminance measurement by the illuminance sensor is performed every predetermined period, and dimming control is performed on the light source based on the calculated ambient illuminance.

Growing community of inventors

Kyoto, Japan

Akinobu Sawada