Sanken Electric Co., Ltd.

Kengo Kimura

Toshihiro Nakano

Mitsutomo Yoshinaga

Toru Ashikaga

Shinji Aso

Yukinari Fukumoto

Kazushige Hirata

Yuji Sayama

Hiroaki Kiuchi

Tooru Ashikaga

Takayuki Yamashita

The present invention supplies desired DC output power to a first LED load and a second LED load whose color temperature is different from that of the first LED load, includes a switching element, ripple current reducers series-connected to the respective LED loads and for reducing current ripples flowing through the LED loads, and a control circuit for controlling the DC output power so that it has a predetermined value, by performing on-off control of the switching element based on a feedback voltage at a connecting point between each of the LED loads and a corresponding one of the ripple current reducers. Each ripple current reducer has feedback-type constant current control circuits for performing control for varying impedance, and the present invention also includes color controllers for performing color control by maintaining a total LED current value of the first and second LED loads at a certain value.

LED driving device and LED lighting apparatus

The present invention is a switching power source device which converts AC power of an AC power source into DC power and outputs the DC power, the device including: a rectifying-smoothing circuit configured to output a rectified-smoothed voltage signal obtained by rectifying and smoothing an AC voltage of the AC power source; a transformer having a primary winding, a secondary winding, and an auxiliary winding; a switching element connected to the primary winding of the transformer; and a control circuit configured to turn the switching element on and off based on a voltage signal which is based on an average value of current flowing through the switching element and the rectified-smoothed voltage signal from the rectifying-smoothing circuit.

Switching power source device and control IC which are capable of performing constant power control

An LED illumination system includes: a load including an LED lamp; and a power supply device, the LED lamp configured to be physically mounted on and demounted from the power supply device, the power supply device comprising: a current feedback control unit; a first voltage comparison unit configured to determine whether the load is in a mounted state; a voltage feedback control unit configured to decrease the voltage of the power supply device to a safe voltage when demounting, and to increase the voltage of the power supply device to perform the constant current control when mounting; and a semiconductor switch element connected in series between the load and the detection resistor, wherein the mounted and demounted states of the load is detected by a voltage of a main electrode of a high potential side of the semiconductor switch element.

Power supply for LED illumination

An LED driving apparatus converts AC input power into predetermined DC output power and supplies the DC output power to an LED load. The LED driving apparatus includes a switching element Qto be turned on and off, a ripple current reducerthat is connected in series with the LED load and reduces current ripples of the LED load, and a controller CNT that turns on and off the switching element according to a feedback voltage taken from a connection point of the LED load and ripple current reducer, thereby controlling the DC output power to a predetermined value.

LED driving apparatus and LED lighting apparatus

The present invention includes a first DC converter converting AC voltage, into DC voltage while correcting a power factor, and a second DC converter electrically isolating the first DC converter from an LED group load, and converting the DC voltage, into a predetermined DC voltage and supply the resultant voltage to the LED group load. The second DC converter includes a current detection circuit disposed on the secondary side, and detecting current flowing into the LED group load, an error amplifier amplifying an error between a detected current value detected and a reference current value, a signal transmission isolation element transmitting a control signal based on an output signal from the error amplifier, to the primary side, and a switching element transferring power to the secondary side through the transformer by being turned on/off according to the control signal.

Power converter

A synchronous operating system for operating a plurality of discharge tube lighting apparatuses at the same frequency and same phase includes (1) an oscillator of a triangular wave signal whose inclination for charging a capacitor Cand inclination for discharging the same are the same, (2) a signal generation part to generate, in a period shorter than a half period of the triangular wave signal, a first drive signal having a pulse width corresponding to a load current, and (3) a signal generation part of a second drive signal having a pulse width substantially equal to that of the first drive signal and a phase difference of about 180 degrees with respect to the same.

Synchronous operating system for discharge tube lighting apparatuses, discharge tube lighting apparatus, and semiconductor integrated circuit

An LED lighting apparatus includes a triac dimmer, a series circuit connected to the triac dimmer and including a primary winding P of a switching transformer T and a switching element Q, the switching transformer having a plurality of windings, a controllerof the switching element, a rectifying-smoothing circuit of a voltage of a secondary winding S of the switching transformer, LEDstoconnected to an output of the rectifying-smoothing circuit, a current detectordetecting a current of the, a voltage detectorconfigured to output a voltage detection signal of a voltage generated at one of the secondary winding when the first rectifying element is ON, the voltage at the secondary winding being proportional to the phase-controlled AC voltage, and an amplifieramplifying a signal that is based on the current detection signal and voltage detection signal for the controller.

LED lighting apparatus

A DC/AC converter includes: a resonant circuit including a transformer having a primary winding and a secondary winding and at least one capacitor, in which the capacitor is connected to at least one of the primary winding and secondary winding of the transformer, and an output terminal to which the load is to be connected is provided on the secondary winding side; a switching circuit connected to both ends of a direct current power supply and having a bridge configuration composed of switching elements for flowing a current through the primary winding of the transformer and the capacitor in the resonant circuit; and a control circuit that turns on/off the switching elements by a pair of drive signals, and flows a current through the load bidirectionally, thereby performs a PWM control for the current flowing through the load, wherein the control circuit includes step drive circuits which turn on the switching elements in steps, and the step drive circuits are provided so as to individually correspond to the switching elements.

DC/AC converter

An apparatus for lighting LEDs includes an LED group load having the LEDs, a converter to generate a voltage applied to the LED group load, a current controller to control a current of the LED group load, a voltage controller to control an output voltage provided by the converter, a time division circuit to intermittently pass a current through the LED group load, and a selector. The selector, during a period in which the time division circuit passes a current through the LED group load, selects the current controller to control a current of the LED group load and thereby control an output voltage provided by the converter, and during a period in which the time division circuit passes no current through the LED group load, selects the voltage controller to control an output voltage provided by the converter.

Apparatus for lighting LEDs

A current balancing apparatus includes a first transformer having a first primary winding and a first secondary winding electromagnetically coupled with the first primary winding, the first primary winding having a first end connected to a first load that passes a first current; a second transformer having a second primary winding and a second secondary winding electromagnetically coupled with the second primary winding, the second primary winding having a first end connected to a second load that passes a second current having an AC component substantially having a 180-degree phase difference with respect to the first current; and a series circuit including the first secondary winding, the second secondary winding, and a current smoother, to balance the first current and second current with each other.

Current balancing apparatus, current balancing method, and power supply apparatus

A DC/AC converter includes a resonant circuit having a first capacitor connected to at least one of a primary winding and a secondary winding of a transformer and an output end connected to a load, the resonant circuit receiving an alternating signal having a predetermined frequency and amplitude to pass a current, a variable impedance element connected in parallel with a part of the output end of the resonant circuit, the variable impedance element changing the impedance value thereof according to a current passing through the load, and a controller to control the current passing through the load to a predetermined value by changing the resonant frequency of the resonant circuit according to the changed impedance value of the variable impedance element.

DC/AC converter and controller thereof

An AC conversion circuit includes a main transformer having a primary winding and a secondary winding to electrically insulate the AC power source side and the discharge tube side from each other, an ICarranged on the AC power source side, a plurality of switching elements arranged on the AC power source side and driven by the IC, to pass a current through the primary winding of the main transformer based on the DC power, an ICarranged on the discharge tube side, to generate a pair of rectangular-wave signals for conducting PWM control on a current passing through the discharge tube and having the same pulse width with a duty ratio of less than 50% and a phase difference of about 180 degrees, and one or more signal transfer insulated elements to send the pair of rectangular-wave signals from the ICto the IC. The ICdrives the plurality of switching elements according to the pair of rectangular-wave signals from the one or more signal transfer insulated elements, so that positive-negative symmetrical AC power is supplied from the secondary winding of the main transformer to the discharge tube.

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Niiza, Japan

Kengo Kimura