Power supply device

• US 5,771,159 A
• Filed: 07/10/1997
• Issued: 06/23/1998
• Est. Priority Date: 11/25/1994
• Status: Expired due to Term

• Current Assignee: Panasonic Electric Works Company Limited (Panasonic Holdings Corporation)
• Original Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Inventors: Yamanaka, Masahiro, Sako, Hiroyuki, Nishiura, Koji
• Primary Examiner(s): Wong, Peter S.
• Assistant Examiner(s): JARDIEU, DEREK
• Application Number:
  US08/891,060
• Time in Patent Office: 348 Days
• Field of Search: 363/97, 363/131, 363/17, 363/37, 363/98, 363/132
• US Class Current: 363/17
• CPC Class Codes: H02M 1/425 using a single converter stage both for correction of AC input power factor and generation of a high frequency AC output voltage
• CPC Class Codes: H02M 7/48 using discharge tubes with control electrode or semiconductor devices with control electrode
• CPC Class Codes: H02M 7/4815 Resonant converters H02M7/4811 and H02M7/4826 take precedence
• CPC Class Codes: H05B 41/28 using static converters
• CPC Class Codes: H05B 41/2825 by means of a bridge converter in the final stage H05B41/285 takes precedence
• CPC Class Codes: Y02B 70/10 Technologies improving the efficiency by using switched-mode power supplies [SMPS], i.e. efficient power electronics conversion e.g. power factor correction or reduction of losses in power supplies or efficient standby modes

Abstract

A power supply device in which an inverter circuit is supplied with power directly from a rectification circuit, the inverter circuit has a pair of switching elements connected in series with each other and connected between both ends of the rectification circuit through an impedance element, a series circuit of the impedance element, two capacitors and an inductor is connected in parallel to one of the switching elements of the inverter circuit connected to positive polarity one of the both ends of the rectification circuit, a load is connected across one of the capacitor, a valley filling circuit receives an output of the inverter circuit through a diode provided in the valley filling circuit and supplies it to a power supply capacitor provided therein and, when a DC output voltage of the rectification circuit drops, the valley filling circuit supplies power to the inverter circuit via the power supply capacitor and another diode provided therein. Thereby, fluctuations in a current supplied to the load can be effectively reduced.

Claims

1. A power supply device comprising:

rectifying means for rectifying AC power and providing a pulsating DC output voltage;

inverter means connected to said rectifying means for converting the pulsating DC output voltage to a high frequency output voltage and supplying the high frequency output voltage to a load, said inverter means including first and second switching elements connected in a first series circuit, one of said first and second switching elements being ON when the other of said first and second switching elements is OFF, an impedance element connected between said rectifying means and said first series circuit, and a resonant circuit including a capacitor and a first inductor for providing a resonant output voltage to the load, said resonant circuit and said impedance element forming a second series circuit connected in parallel with one of said first and second switching elements; and

valley-filling means for accumulating energy from said inverter means when the pulsating DC output voltage has a relatively high amplitude and for supplying accumulated energy across said first series circuit when the pulsating DC output voltage has a relatively low amplitude, said valley-filling means including;

a third series circuit comprising a first valley-filling capacitor, a second inductor, and a first diode, said third series circuit being connected across said first series circuit;

a second diode for rectifying the high frequency output voltage of said inverter, charging said first valley-filling capacitor, and connected between said inverter means and a junction of said second diode and said first valley-filling capacitor; and

a second valley-filling capacitor connected across said first series circuit.

2. The power supply device as set forth in claim 1, wherein said second diode has an anode connected to a junction of said first and second switching elements, said first and second diodes form a fourth series circuit connected across one of said first and second switching elements, and said second diode, said second inductor, and said first valley-filling capacitor form a fifth series circuit connected across the other of said first and second switching elements.

3. The power supply device as set forth in claim 1, wherein

said second diode has a cathode connected to a junction of said first and second switching elements;

said second diode, said second inductor, and said first valley-filling capacitor form a fourth series circuit connected across one of said first and second switching elements; and

said first and second diodes form a fifth series circuit connected across the other of said first and second switching elements.

4. The power supply device as set forth in claim 1, wherein said first inductor includes a feedback winding connected to said second diode providing the high frequency output voltage for charging said first valley-filling capacitor.

5. The power supply device as set forth in claim 1, wherein said inverter means includes a third diode connected in parallel with said impedance element.

6. A power supply device comprising:

a rectifying circuit for rectifying AC power and providing a pulsating DC output voltage;

an inverter circuit connected to said rectifying circuit for converting the pulsating DC output voltage to a high frequency output voltage and supplying the high frequency output voltage to a load, said inverter circuit including first and second switching elements connected in a first series circuit, one of said first and second switching elements being ON when the other of said first and second switching elements is OFF, an impedance element connected between said rectifying circuit and said first series circuit, and a resonant circuit including a capacitor and an inductor for providing a resonant output voltage to the load, said resonant circuit and said impedance element forming a second series circuit connected in parallel with one of said first and second switching elements;

a valley-filling circuit connected to output terminals of said inverter circuit and including means for accumulating energy output by said inverter circuit and for discharging accumulated energy to said inverter circuit when the high frequency output voltage applied to said valley-filling circuit falls below a peak of the high frequency output voltage, said valley-filling circuit including a plurality of capacitors and a pluralitv of diodes respectively connected so that each of the capacitors is series connected to two of said diodes arranged in opposite polarities for discharging each of said capacitors through respective different paths; and

means connecting said valley-filling circuit across said first series circuit.

7. The power supply device as set forth in claim 6, wherein said plurality of capacitors and said plurality of diodes includes a third series circuit of first and second capacitors and a first diode interposed between said first and second capacitors, a second diode connected across a fourth series circuit formed by said first capacitor and said first diode with the cathode of said first diode connected to the anode of said second diode, and a third diode connected across a fifth series circuit formed by said second capacitor and said first diode, the anode of said first diode being connected to the cathode of said third diode, said first and second capacitors being charged through a path including said first diode and discharged through paths including said second and third diodes.

8. The power supply device as set forth in claim 6, wherein said valley-filling circuit begins discharging energy accumulated in a charged one of said capacitors when the high frequency output voltage falls below two-thirds of a peak voltage to which said capacitor is charged.

9. A power supply device comprising:

a rectifying circuit for rectifying AC power and providing a pulsating DC output voltage;

a valley-filling power supply circuit for increasing an output voltage between peaks of the pulsating DC output voltage;

an inverter circuit for converting an output voltage of said valley-filling power supply circuit into a high frequency output voltage and supplying the high frequency output voltage to a load;

a high frequency feedback circuit for feeding back the high frequency output voltage and superimposing the high frequency output voltage on the pulsating DC output voltage wherein said valley-filling power supply circuit comprises a first capacitor connected at a first terminal to a first output terminal of said rectifying circuit, a second capacitor connected at a first terminal to a second output terminal of said rectifying circuit, a first diode having an anode connected to a second terminal of said first capacitor and a cathode connected to a second terminal of said second capacitor, a second diode having an anode connected to said cathode of said first diode and a cathode connected to said first terminal of said rectifying circuit, and a third diode having a cathode connected to said anode of said first diode and an anode connected to said second terminal of said rectifying circuit.