Patent application number | Description | Published |
20110309767 | LIGHT-EMITTING ELEMENT DRIVE DEVICE - A light-emitting element drive device capable of expanding a dimming range of a light-emitting element, enabling a constant minimum dimmed luminance to be obtained irrespective of individual differences between devices. A burst signal generating circuit | 12-22-2011 |
20110316510 | LOAD DRIVE DEVICE - A load drive device capable of expanding a range of an output power by improving a linearity thereof when the output power varies. This device includes an output circuit | 12-29-2011 |
20120262070 | LIGHT EMITTING ELEMENT DRIVE DEVICE - A light emitting element drive device includes a light emitting unit that includes a light emitting element and that performs dimming based on a pulse width modulation (PWM) signal, a first switching element that is turned ON or OFF based on the PWM signal and that is connected in series to the light emitting unit, and a protection circuit that includes a charging circuit and a second switching element. The second switching element is turned ON when a first voltage obtained by a charging operation of the charging circuit is equal to or more than a first predetermined value. The charging circuit discharges electric charge through the first switching element when a second voltage between input and output terminals of the first switching element drops. The first switching element is turned OFF despite the existence of the PWM signal when the second switching element is turned ON. | 10-18-2012 |
20120306386 | LED DRIVE DEVICE AND LED ILLUMINATING DEVICE - An LED drive device whose power dissipation can be effectively reduced without halting current supply to an LED row as well as an LED illuminating device with the LED drive device incorporated therein. When an LED | 12-06-2012 |
20130076258 | POWER SUPPLY DEVICE AND LIGHT-EMITTING ELEMENT DRIVE DEVICE - A power supply device includes a converter and an arithmetic circuit. The arithmetic circuit calculates a present control command value at predetermined intervals based on a digital value, which reflects an output voltage of a converter, from a conversion circuit. The arithmetic circuit calculates the difference value between the present control command value and a previous control command value. Based on the difference value, it is determined whether a signal output circuit outputs a high-level signal toward a charge terminal or a low-level signal toward a discharge terminal. As a result, the number of output lines corresponds to at least the number of charge terminals and discharge terminals. The above features can be achieved with a simple circuit configuration by adding a discharge and charge circuit and without increasing the number of output lines. | 03-28-2013 |
20130076259 | POWER SUPPLY DEVICE AND LIGHT-EMITTING ELEMENT DRIVE DEVICE - A power supply device includes a convertor and an arithmetic circuit. The convertor supplies electric power by performing an ON and OFF operation of a switching element. The arithmetic circuit calculates a control command value at predetermined intervals based on a digital value, which reflects an output voltage of the convertor, from a conversion circuit. Based on the control command value, a pulse signal generation circuit determines a duty ratio of a pulse signal to make the output voltage of the convertor stable. A driving signal with a finely adjusted duty ratio can be generated by an operation clock signal having a lower frequency than a conventional device. As a result, the number of output lines is appropriate if there is at least a single output line for the pulse signal from the pulse signal generation circuit. | 03-28-2013 |
20130099834 | RAMP SIGNAL GENERATION CIRCUIT AND RAMP SIGNAL ADJUSTMENT CIRCUIT - A ramp signal generation circuit comprises a first input terminal that receives a clock signal, a plurality of second input terminals that receive high-level or low-level signals, and a discharge and charge circuit that discharges and charges the capacitor and that outputs a ramp signal corresponding to a voltage generated by the capacitor. The discharge and charge circuit comprises a discharge circuit that discharges the capacitor, and a charge circuit that is configured with a plurality of paired resistors and rectifying elements connected between the capacitor and the plurality of second input terminals. The discharge and charge circuit selects at least one of the plurality of second input terminals so as to change a current value for charging the capacitor by inputting the high-level signal to the selected one of the plurality of second input terminals. | 04-25-2013 |
20130147399 | LIGHT EMITTING ELEMENT DRIVE DEVICE AND LIGHTING DEVICE - A light emitting element drive device includes an electric conduction switch that is provided along a power input line, a voltage detection unit that detects a power source voltage containing a noise component when the electric power is supplied to the power input line, a conversion processing unit that converts the detected power source voltage containing the noise component to a digital value, a data generation unit that generates data of a predetermined number of bits, and a control unit that turns on the electric conduction switch. The control unit determines a delay time based on the predetermined number of bits. The delay time corresponds to a time between supplying the electric power to the power input line and turning on the electric conduction switch. The control unit turns on the electric conduction switch after the delay time passes. Thus, an excessive rush current is prevented. | 06-13-2013 |
20130187570 | LIGHT EMITTING ELEMENT DRIVE DEVICE - A light emitting element drive device with PWM dimming includes an LED module, a power conversion circuit that supplies electric power to the LED module, a dimming switch element that performs an open/close operation for a path in which a current flows in the LED module, and a voltage detection circuit that detects a voltage value of a voltage that is output from the power conversion circuit. When the dimming switch element is turned ON, a control circuit performs feedback control so as to make a current value of the current close to a first target value. When the dimming switch element is turned OFF, the control circuit performs feedback control so as to make the voltage value close to a second target value. Wherein, the first target value is a predetermined value and the second target value is set based on the voltage value. | 07-25-2013 |
20140036547 | POWER SUPPLY DEVICE - A power supply device includes a control unit performing PFM control for a switching element, a voltage detection unit detecting an output voltage of a converter, and a signal generation circuit. The control unit calculates a first control command value based on the output voltage, calculates a new first control command value adjusting the output voltage to a target voltage, calculates a difference value therebetween, and outputs a voltage, which has a polarity corresponding to the difference value, for a first output period corresponding to the difference value. The signal generation circuit generates a pulse signal in which a frequency increases or decreases in accordance with a first command value voltage corresponding to a charged voltage at a storage element according to the new first control command value. The switching element is driven by the pulse signal that has a finer adjustment unit frequency. | 02-06-2014 |