Rohm Co., Ltd.

Ryosuke Kanemitsu

Koji Katsura

Masaaki Nakayama

Kenichi Fukumoto

Junichi Itai

Nobuaki Matsui

Kouji Miyamoto

Seiji Nakashima

Keisuke Miura

An LED driving device includes: a plurality of LED terminals (LEDto LEDterminals) to have connected to them the cathodes of LEDs in a plurality of channels; a lowest voltage input terminal (MINSELIN); a lowest voltage output terminal (MINSELOUT); and a selector. When the lowest voltage input terminal is used, the selector selects the lowest among the voltages at the plurality of LED terminals and the voltage at the lowest voltage input terminal, to output the lowest voltage from the lowest voltage output terminal; when the lowest voltage input terminal is not used, the selector selects the lowest among the voltages at the plurality of LED terminals, to output the lowest voltage from the lowest voltage output terminal.

LED driving device, LED light source device, and vehicle onboard display device

In an LED driving device, a DC-DC controller performs control such that the voltage at an LED terminal remains equal to a reference voltage, and a reference voltage generator generates the reference voltage such that it decreases as the set value of the LED current set by an LED current setter decreases.

LED driving device, lighting device, and vehicle-mounted display device

This LED driving device comprises: a DC/DC controller which controls an output stage for supplying an output voltage to an LED; and a current driver which generates an output current of the LED, wherein the current driver performs PWM dimming by turning on the output current in accordance with an LED-current-on period of a PWM dimming signal and turning off the output current in accordance with an LED-current-off period of the PWM dimming signal, and the DC/DC controller includes a feedback control unit which performs feedback control for outputting a switching pulse to the output stage so as to make a cathode voltage of the LED equal to a reference voltage, and a pulse addition control unit which performs pulse addition control for adding a predetermined pulse number of additional switching pulses at a time of switching between the LED-current-on period and the LED-current-off period.

Led driving device, lighting device, and vehicle-mounted display device

An LED driving device includes a DC/DC controller which controls an output stage for supplying an output voltage to an LED; and a current driver which generates an output current of the LED. The current driver performs PWM dimming by turning on the output current in accordance with an LED-current-on period of a PWM dimming signal and turning off the output current in accordance with an LED-current-off period of the PWM dimming signal. The DC/DC controller includes a feedback control unit which performs feedback control for outputting a switching pulse to the output stage so as to make a cathode voltage of the LED equal to a reference voltage. A pulse addition control unit performs pulse addition control for adding a predetermined pulse number of additional switching pulses at a time of switching between the LED-current-on period and the LED-current-off period.

An LED drive circuit drives an LED module. The LED module has a light-emitting diode, and an identification unit having characteristic information relating to light-emitting characteristics of the light-emitting diode. The LED drive circuit includes a detection unit and a drive circuit. The detection unit is provided for detecting characteristic information, and generates a detection signal that corresponds to the characteristic information. The drive circuit generates drive current by a drive signal supplied according to the characteristic information based on the detection signal, and supplies the drive current to drive the light-emitting diode.

LED drive circuit, LED drive device, and LED drive system

A light emitting element driving apparatus includes the following: current source; error amplifier generating error signal based on comparison of a first reference voltage with the highest voltage among total forward drop voltages of element arrays or feedback voltage corresponding to a drive voltage; first and second switches for ON/OFF control to apply the feedback voltage to first and second input terminals of the error amplifier respectively; slope voltage generating circuit; PWM comparator generating a pulse modulation signal; drive amplifier controlled by the pulse modulation signal and drives a switching element supplying the drive voltage to the element arrays; PWM width detector that outputs a pulse width detection signal having different levels between when the pulse width is less than predetermined threshold value and when equal to or greater than the threshold value, and switches ON/OFF of the first and second switches based on the pulse width detection signal.

Light emitting element driving apparatus and driving method thereof

The present invention provides a light emitting diode (LED) driving device as a semiconductor device, which comprises: a direct current/direct current (DC/DC) controller, for controlling an output segment that is used to generate an output voltage from an input voltage and supply the output voltage to an LED; an output current driver, for generating an output current of the LED; and an LED short-circuit detection circuit, for monitoring a cathode voltage of the LED to perform an LED short-circuit detection, wherein the LED short-circuit detection circuit controls whether an action is performed or not according to a short-circuit detection enable signal input from outside the LED driving device.

LED driving device, illuminator, and liquid crystal display device

The present invention provides a light emitting diode (LED) driving device, which comprises: a direct current/direct current (DC/DC) controller, for controlling an output segment that is used to generate an output voltage from an input voltage and supply the output voltage to an LED; an output current driver, for generating an output current of the LED; and an output discharging circuit, for performing, based on a predetermined control signal, discharging of the output voltage when a generation action of the output voltage and the output current stops.

LED driving device, illuminator, and Liquid Crystal Display device

The load driving device disclosed in the specification includes a controller to generate a first control signal based on an input signal, a first output transistor to supply an output current to a load according to the first control signal, a first dividing circuit to output a first divided voltage by dividing a voltage across a first primary electrode and a second primary electrode of the first output transistor by a first transistor and a second transistor connected in serial, a first voltage generating circuit to output a first reference voltage, and a first comparator to supply a first over current detection signal to the controller based on the first reference voltage and the first divided voltage.

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Kyoto, Japan

Ryosuke Kanemitsu