Sanken Electric Co., Ltd.

Polar Semiconductor, Inc.

Shohei Osaka

Michael J Gaboury

Gregory J Rausch

Akio Iwabuchi

Yoichi Kyono

Hiroaki Nakamura

Satoru Washiya

Yoichi Terasawa

A light emitting element driving device, which flashing-drive a plurality of light emitting element arrays connected in parallel by switching elements connected in series with each of the plurality of light emitting element arrays, the light emitting element driving device including: a current detection unit configured to detect respective currents flowing through each of the plurality of light emitting element arrays as currents of the light emitting element arrays; a selection unit configured to select the smallest current of the light emitting element arrays of the detected currents obtained by the current detection unit; and an output voltage control unit configured to control output voltage supplied to the plurality of light emitting element arrays so that the current of the light emitting element arrays selected by the selection unit becomes a preset reference current value.

Light emitting element driving device

A method of controlling a power factor correction (PFC) converter having a first PFC sub-circuit and a second PFC sub-circuit determines when to transition the PFC converter between an interleaved mode and a saving energy mode (SEM). The method includes generating an amplified error signal based on a monitored output voltage of the PFC converter. The second PFC sub-circuit is disabled in response to the amplified error signal being less than a first threshold value and enabled in response to the amplified error signal exceeding a second threshold value.

Saving energy mode (SEM) for an interleaved power factor correction (PFC) converter

A power source apparatus includes a first converter having a reactor L, a switching element Q, and a rectifier D; a second converter connected in parallel with the first converter and having a reactor L, a switching element Q, and a rectifier D; a capacitor Cconnected to output ends of the first and second converters; a current detector Rdetecting a resultant current of currents of the first and second converters; a controllerdriving the switching element Qand the switching element Q; and a selector. In a case where the resultant current indicates a first reference value, if one of first and second drive signals of the controller is active, the active drive signal is deactivated, and if both the first and second drive signals are active, one of the first and second drive signals that is active longer than the other is deactivated.

Power source apparatus

A power conversion apparatus includes a converter having an input power source Vin, a reactor L, a switching element Q, and a rectifying element D, a smoothing capacitor Cconnected to an output terminal of the converter, and a controllerto turn on/off the switching element and thereby control power to be outputted from the converter. The controller has a pulse generatorto generate a pulse signal according to an input voltage to the converter and an output voltage from the converter, the pulse signal being used to turn on/off the switching element. The controller also has an adjusterto mask an ON time of the pulse signal for a predetermined time and thereby provide the pulse signal with an adjusted ON time, the adjusted ON time determining a duty ratio at which the switching element is turned on/off.

Power conversion apparatus and controller thereof

A controller provides frequency compression for an interleaved power factor correction (PFC) converter that determines the ON and OFF times of each switch associated with the PFC converter to prevent operating frequencies in the audible range. The controller includes a first circuit for generating an ON time current source having a magnitude related to an amplified error signal and the monitored input voltage, and a second circuit for generating an OFF time current source having a magnitude related to the ON time current source, the monitored input voltage, and the monitored output voltage. Gate drive circuitry provides gate drives signals to the switches of the interleaved PFC converter at a frequency determined by magnitudes of the ON time current source and the OFF time current source.

Frequency compression for an interleaved power factor correction (PFC) converter

The present invention provides a method of controlling an interleaved power factor correction (PFC) circuit operating in a discontinuous conduction mode (DCM). The controller employs a normal mode of operation in which inductor currents in each PFC sub-circuit are estimated based on the monitored input voltage and monitored output voltage, and switching devices associated with each PFC sub-circuit are controlled to ensure DCM operation. As the input voltage increases, the OFF times of each PFC sub-circuit increase such that the inductor currents no longer overlap. In response, the controller activates a time-limiting mode (TLM) in which OFF time durations for each sub-circuit are based on the monitored sum of load currents as opposed to the monitored input voltage and monitored output voltage.

Time-limiting mode (TLM) for an interleaved power factor correction (PFC) converter

A capacitive load driver includes a first switching element whose first end receives positive potential, an EL element arranged between a second end of the first switching element and the ground, a charge collecting capacitor whose first end is connected to a positive electrode terminal of the EL element, a voltage source connected between a second end of the charge collecting capacitor and the ground, and a controller. The controller charges a parasitic capacitance of the EL element and the charge collecting capacitor, and thereafter, applies negative potential from the voltage source to the second end of the charge collecting capacitor. Thereafter, the controller brings the output voltage of the voltage source to ground potential so that the charge collecting capacitor is discharged to charge the EL element. The capacitance of the charge collecting capacitor is set to be sufficiently greater than that of the parasitic capacitance.

Capacitive load driver

The present invention includes: an input voltage detector detecting an input voltage of a parallel converter and outputting an input voltage signal; an output voltage detector detecting an output voltage of the parallel converter; and a controller. The controller includes an error amplifier comparing the output voltage signal and a reference voltage and outputting an error amplification signal; an arithmetic operator generating an ON time signal and an OFF time signal based on the input and output voltage signals and the error amplification signal; a phase signal generator generating plural phase signals having different phases based on the ON and OFF time signals and the error amplification signal; a pulse generator generating plural pulse-train signals synchronized with the respective phase signals based on the ON time signal, the error amplification signal and the phase signals; and a driver driving the switching units in accordance with the pulse-train signals.

Interleaved converter

A power factor correction circuit includes a first rectifier to rectify an AC voltage, a series circuit connected to an output of the first rectifier and including a step-up reactor and a switching element, a rectifying-smoothing circuit connected to both ends of the switching element and including a second rectifier and a smoothing capacitor, an input voltage detector to detect an output voltage of the first rectifier, an output voltage detector to detect a voltage across the smoothing capacitor, an error amplifier to amplify an error between the output voltage signal and a reference voltage, and a controller to determine an ON/OFF duty ratio of the switching element according to the amplified error signal and a result of a calculation carried out on the input voltage signal and output voltage signal.

Duty cycle controller for power factor correction circuit

A DC-DC converter includes: a first series circuit in which a resonance reactor, a primary winding of a transformer, and a switching element are connected in series, the first series circuit being connected to both ends of a direct current power supply; a second series circuit in which a first rectifier, a current resonance capacitor, and a secondary winding of the transformer are connected in series, the second series circuit being connected to both ends of the direct current power supply; a rectifying/smoothing circuit having a second rectifier and a smoothing capacitor and connected to both ends of a series circuit of the current resonance capacitor and the secondary winding of the transformer; an output voltage detection circuit that detects an output voltage of the rectifying/smoothing circuit; and a control circuit that turns on and off the switching element based on an output voltage signal from the output voltage detection circuit.

High efficiency DC-DC converter for reduced switching loss

A level-shift circuit converts a first voltage level into a second voltage level different from the first voltage level. The level-shift circuit includes a first high-side signal detection circuit, a second high-side signal detection circuit, a drive circuit and electric current detection circuits. The first high-side signal detection circuit sets a logical voltage state of the second voltage level via a first capacitor. The second high-side signal detection circuit resets the logical voltage state of the second voltage level via a second capacitor. The drive circuit on-off drives a high-side switch connected to a low-side switch in series by a set signal of the first high-side signal detection circuit and a reset signal of the second high-side signal detection circuit. The electric current detection circuits detect an electric current flowing into or from the first and/or second capacitors.

Level-shift circuit

A level shift circuit shifts a first voltage level to a second voltage level that is different from the first voltage level. The level shift circuit includes a set-level circuitconfigured to detect and transmit a set signal that is used to set a logic voltage state based on the second voltage level, a reset-level circuitconfigured to detect and transmit a reset signal that is used to reset the logic voltage state based on the second voltage level, and a reference-level circuit Cconfigured to provide a reference signal that is used to detect the set signal and reset signal based on the second voltage level. The set-level circuit, reset-level circuit, and reference-level circuit transmit signals from the first voltage level to the second voltage level through capacitors C, C, and C, respectively.

Level shift circuit

A resonant switching power source device is provided which comprises first and second MOS-FETsandconnected in series to a DC power source, a first transformerwhich has a first primary windingconnected in parallel to first or second MOS-FETorand in series to a first capacitor, a first rectifying smootherconnected between a secondary windingof first transformerand first output terminals, a second transformerwhich has a primary windingconnected in parallel to primary windingof first transformer, and a second rectifying smootherand an output-regulatory MOS-FETconnected between a secondary windingin second transformerand second DC output terminalsandto control peak current flowing through primary windings of transformersandand rectifying smoothersandin secondary sides for improvement in power conversion efficiency and to produce stable DC outputs of desired level from a plurality of output terminalsand

Resonant switching power source device

An induction heating apparatus capable of stably operating at least one switching element contained therein is provided with a control circuitwhich comprises a resonance waveform detectorfor detecting a high frequency AC waveform supplied from an inverter circuitto a heating coilto produce a detection signal DScorresponding to high frequency AC power waveform; a phase comparatorfor producing an adjusting signal PH corresponding to a phase difference between detection signal DSfrom resonance waveform detectorand drive signal Dfrom drive circuit 7; and an addition circuitfor superimposing the drive signal Dfrom drive circuiton detection signal DSfrom resonance waveform detectorto supply to phase comparatorthe superimposed signal on a level same as or over operation threshold value Vfor the phase comparator.

Induction heating apparatus capable of stably operating at least one switching element contained therein

A switching power supply includes a first series circuit formed by connecting first and second switching elements in series at both ends of a direct-current power source, a second series circuit formed by connecting a resonant capacitor, a resonant reactor, and a primary winding of a transformer in series at both ends of the switching element, a rectifying-smoothing circuit configured to rectify and smooth a voltage generated on a secondary winding of the transformer, and a control circuit configured to turn the first and second switching elements and on and off alternately based on an output voltage from the rectifying-smoothing circuit. Here, the control circuit sets an on-period of the second switching element to a predetermined time period longer than a half value of a cycle of a resonant current attributable to the resonant reactor and the resonant capacitor, and controls an on-period of the first switching element based on the output voltage from the rectifying-smoothing circuit.

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Niiza, Japan

Shohei Osaka