Sanken Electric Co., Ltd.

Yoichi Kyono

Akio Iwabuchi

Hiroshi Usui

Ryuichi Furukoshi

Shohei Osaka

Makoto Sato

Akiteru Chiba

Yoichi Terasawa

Provided is a switching power-supply device capable of balancing a plurality of converter blocks operated in parallel. The switching power-supply device includes a first series circuit of first and second switching elements, a second series circuit of third and fourth switching elements, which circuits are connected in parallel with a power supply, and a control circuit that turns on-and-off the first and second switching elements, alternately, with an arbitrary frequency and turns on-and-off the third and fourth switching elements, alternately, with the same frequency as the arbitrary frequency. The control circuit controls a phase difference of switching signals of the first and second series circuits.

Current balance circuit of resonant type switching power-supply circuit

Provided is a highly-efficient switching power-supply device having a wide input voltage range. The switching power-supply device includes: a first series circuit including first and second switching elements and a second series circuit including third and fourth switching elements, which are connected in parallel with a power supply; a series resonance circuit including a primary coil and a capacitor connected in parallel with the second switching element; a reactor connected between a connection point of the third and fourth switching elements and the capacitor; a transformer having the primary coil and a secondary coil; and a control circuit that turns on-and-off the first and second switching elements, alternately, and turns on-and-off the third and fourth switching elements, alternately. The control circuit switches the first and second series circuits when an input voltage is low and switches only the first series circuit when the input voltage is high.

Switching power-supply device having wide input voltage range

A switching power-supply device includes: a first series circuit including a first switching element; and a second switching element, a second series circuit including a third switching element and a fourth switching element; and a control unit that, while making frequencies of switching signals of the first series circuit and the second series circuit be the same, performs control of turning on-and-off the first switching element and the second switching element, alternately, with dead time at which the first switching element and the second switching element become off and turning on-and-off the third switching element and the fourth switching element, alternately, with dead time at which the third switching element and the fourth switching element become off, wherein the control unit controls a phase difference between the switching signal of the first series circuit and the switching signal of the second series circuit.

Switching power-supply device

A switching power source apparatus has a pulse generator of a first pulse. A first resonant series circuit receives the first pulse signal and passes a current having a 90-degree phase delay with respect to the first pulse signal. The current of the first resonant series circuit turns on/off a switching element Q. A second resonant series circuit receives the second pulse signal and passes a current having a 90-degree phase delay with respect to the second pulse signal. The current of the second resonant series circuit turns on/off a switching element Q. The pulse generator has a third transformer Tthat has secondary windings to output the first and second pulse signals according to a voltage that is applied to the third transformer and is synchronized with drive signals for the switching elements Qand Q

Self power source apparatus

In conventional multi-output switching power supply device, power is supplied from a relatively high voltage side output to a relatively low voltage side output through a dropper circuit which generates relatively large power loss so as to improve the voltage accuracy of a non-stabilized output, so that power supply efficiency is low and heat generated from the dropper circuit is high. One DC power supply of a plurality of DC power supplies on the secondary side is a stabilized output (24 V output terminal TM) having a voltage stabilizing means for stabilizing the output voltage by feeding back the output voltage to a primary side control circuit, and the rest of the DC power supplies are non-stabilized outputs (12 V output terminals TM) not having a voltage stabilizing means for feeding back the output voltage to the primary side. A step-up/down converter is provided between the output of the non-stabilized output and the output of the stabilized output and power is applied/received between the outputs in accordance with the non-stabilized output voltage and, thus, the voltage accuracy of the non-stabilized output is improved.

Multi-output switching power supply device having a step-up/down converter between a stabilized output and a non-stabilized output

A switching power-supply apparatus includes a first converter, a second converter, an output smoothing capacitor Co, a series resonance circuitand a control circuit. The first converter, in which switching elements Qand Qare connected to both ends of a direct-current power-supply Vin in series, and a capacitor Ciand a primary winding Npof a transformer Tincluding an auxiliary winding Naare connected to both ends of the switching element Qin series, includes diodes Dand Dthat rectify voltages generated in secondary windings Nsand Nsof the transformer T. The second converter, in which switching elements Qand Qare connected to the both ends of the direct-current power-supply Vin in series, and a capacitor Ciand a primary winding Npof a transformer Tare connected to both ends of the switching element Qin series, includes diodes Dand Dthat rectify voltages generated in secondary windings Nsand Nsof the transformer T. The output smoothing capacitor Cosmoothes currents output from the diodes D, D, Dand D. The series resonance circuitincludes a resonance reactor Land a resonance capacitor Cconnected to the auxiliary winding Nain series. The control circuitturns on/off the switching elements Qand Qaccording to a current flowing in the series resonance circuit

Switching power-supply apparatus

A gate driver of a switching element Qincludes transistors Qand Qthat are totem-pole-connected to both ends of a DC power source Vcc, transistors Qand Qthat are totem-pole-connected to both ends of a DC power source Vccand have emitters connected to the gate of the switching element Q, and a transformer Thaving a primary winding and a secondary winding. The primary winding is connected to a collector of one of the transistors Qand Q, and through a capacitor, emitters of the transistors Qand Q. The second winding is connected to bases of the transistors Qand Qand the emitters of the transistors Qand Q. A maximum duty cycle of a pulse signal is determined according to a primary winding voltage of the transformer and a forward base-emitter voltage of the transistors Qand Q

Gate driver

A multiple-output switching power source apparatus has a series resonant circuit connected in parallel with a switch Qand including a primary winding and a current resonant capacitor, a first rectifying-smoothing circuit rectifying and smoothing a voltage of a secondary winding in an ON period of the switch to provide a voltage Vo, a series resonant circuit connected in parallel with the switch and including a primary winding and a current resonant circuit, a second rectifying-smoothing circuit rectifying and smoothing a voltage of a secondary winding in the ON period of the switch Qto provide a voltage Vo, and a control circuit controlling an ON period of a switch Qaccording to the output voltage Voand the ON period of the switch Qaccording to the voltage Voand limit the ON period of the switch Qif the voltage Voexceeds a predetermined voltage.

Multiple-output switching power source apparatus

A multiple-output switching power supply unit includes: a voltage generating circuit Q, Q, Tconfigured to generate a pulse voltage by intermittently interrupting a direct current power supply; a series resonance circuit including a current resonance capacitor Cri, a primary winding Pof a transformer T, and a switching element Q, the pulse voltage generated in the voltage generating circuit being applied to the series resonance circuit; a rectifying/smoothing circuit D, Cconfigured to rectify and smooth a voltage which is generated in a secondary winding Sof the transformer, and thus to output a direct current output voltage; and a control circuitconfigured to turn on and off the switching element based on the direct current output voltage.

Multiple-output switching power supply unit

A multiple-output switching power source apparatus includes a control circuit to adjust a time for applying a DC voltage to a primary winding of a transformer by turning on/off a switching element Q, a first rectifying-smoothing circuit for a first secondary winding of the transformer, a second rectifying-smoothing circuit for a switching element Qto provide a second output voltage connected to an output terminal of the first rectifying-smoothing circuit through the switching element Q, a third rectifying-smoothing circuit for a second secondary winding of the transformer and provide a third output voltage, a first end of the second secondary winding of the transformer being connected to the switching element Q, and a control circuitto adjust an ON/OFF time of the switching element Qaccording to the voltage of the first secondary winding of the transformer, the second output voltage, and the third output voltage.

Multiple output switching power source apparatus

A multiple output switching power source apparatus includes first and second transformers each having a primary winding, a first secondary winding, and a second secondary winding; a first control circuit adjusting a time for applying a DC voltage to the primary winding of the first transformer; a first rectifying-smoothing circuit rectifying and smoothing a voltage generated at the first secondary winding of the first transformer and providing a first output voltage; a second control circuit adjusting a time for applying the DC voltage to the primary winding of the second transformer; a second rectifying-smoothing circuit rectifying and smoothing a voltage generated at the first secondary winding of the second transformer and providing a second output voltage; and a third rectifying-smoothing circuit rectifying and smoothing a voltage across a series winding having the second secondary windings of the first and second transformers and providing a third output voltage.

A multiple output switching power source apparatus includes first and second switching elements Qand Q, a first series resonant circuit connected in parallel with Qor Qand having a first current resonant capacitor and a primary winding of a transformer that are connected in series, a first rectifying-smoothing circuit to rectify and smooth a voltage generated by a secondary winding of the transformer, a second series resonant circuit connected in parallel with the secondary winding and having a second current resonant capacitor and a second resonant reactor that are connected in series, a second rectifying-smoothing circuit to rectify and smooth a voltage of the second series resonant circuit, and a control circuit to determine an ON period of Qaccording to a voltage obtained from one of the first and second rectifying-smoothing circuits, determine an ON period of Qaccording to a voltage obtained from the other of the first and second rectifying-smoothing circuits, and alternately turn on/off Qand Q

Multiple output switching power source apparatus including multiple series resonant circuits

A DC power source device is provided which comprises conduction detectorsfor producing detection signals V, Vduring the detective period of rectification MOS-FETsand timer circuitsconnected to polarity detectors. Timer circuitscount output time of detection signal V, Vfrom polarity detectorsuntil electric current through one of rectification MOS-FETscomes to zero, and turns the other of rectification MOS-FETsoff immediately before termination of the counted time so that timer circuitscan reliably turn rectification MOS-FETsoff during the conductive period of forward current flow for efficient synchronous rectification.

DC power source device with timer controlled synchronous rectifiers in the secondary

A device for driving switching elements is provided with a potential detectorwhich provides drive circuitwith signals in response to differences among potentials at junctionstoof first and third resistors, third resistorand first control MOS-FET, second and fourth resistorsand fourth resistorand second control MOS-FETso that drive circuitsupplies drive signals to a gate terminal of a first MOS-FETbased on potentials in first and second series circuitsand. When appropriate resistance values are selected for first to fourth resistorsto, potential detectorprecisely detects the potential at each junctiontoto produce detection signals and prevent malfunction of drive circuiteven upon occurrence of abnormal signals or noises resulted from abrupt potential rise.

Device for driving switching elements

A multi-output switching power supply of the present invention includes: a series resonant circuit which is connected in parallel with a first switching element or a second switching element, and includes a current resonance capacitor, a resonant reactor and a primary winding of a transformer, which are connected in series; a first rectifying and smoothing circuit which rectifies and smoothes a voltage generated in a first secondary winding of the transformer, and outputs a first output; a second rectifying and smoothing circuit which has a first diode for rectifying a voltage generated in a second secondary winding of the transformer, a reactor having energy stored therein by the voltage rectified by the first diode and a second diode for regenerating the energy into an output, and which rectifies a current flowing through the reactor and outputs a second output; and a control circuit which alternately turns on and off the first and second switching elements based on the first output.

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Niiza, Japan

Yoichi Kyono