Power supply circuit and power supply device

Patent metadata

Field	Value
Publication number	US-12062976-B2
Application number	US-202217703486-A
Country	US
Kind code	B2
Filing date	Mar 24, 2022
Priority date	May 21, 2021
Publication date	Aug 13, 2024
Grant date	Aug 13, 2024

Abstract

A power supply circuit of a step-down type, configured to generate an output voltage at a predetermined level from an alternating current (AC) voltage. The power supply circuit includes a rectifier circuit configured to rectify the AC voltage, a first line coupled to the rectifier circuit, a second line on a ground side, a switch coupled between the first line and the second line, and a control circuit configured to control the switch to bring a level of the output voltage to the predetermined level. The power supply circuit is free of an inductor interposed between the first line and the rectifier circuit.

First claim

What is claimed is:

1. A power supply circuit of a step-down type configured to generate an output voltage at a predetermined level from an alternating current (AC) voltage, the power supply circuit comprising:
a rectifier circuit configured to rectify the AC voltage;
a first line coupled to the rectifier circuit;
a second line on a ground side;
a switch coupled between the first line and the second line; and
a control circuit configured to control the switch to bring a level of the output voltage to the predetermined level, wherein
the power supply circuit is free of an inductor interposed between the first line and the rectifier circuit;
the rectifier circuit has a first input terminal and a second input terminal; and
the power supply circuit further includes:
a first capacitor coupled to the first input terminal of the rectifier circuit, and
a second capacitor coupled to the second input terminal of the rectifier circuit, wherein
the AC voltage is applied to the first and second capacitors.

2. The power supply circuit according to claim 1 , further comprising:
a diode having an anode and a cathode, the anode being coupled to the first line; and
a capacitor coupled to the cathode of the diode, the capacitor being configured to generate the output voltage.

3. The power supply circuit according to claim 1 , wherein
the control circuit is configured to
turn off the switch when the level of the output voltage is at a first level, and
turn on the switch when the level of the output voltage is at a second level higher than the first level.

4. The power supply circuit according to claim 1 , wherein
the rectifier circuit is a full-wave rectifier circuit configured to perform full-wave rectification to the AC voltage.

5. The power supply circuit according to claim 1 , wherein the switch is a metal-oxide semiconductor (MOS) transistor having
a drain coupled to the first line, and
a source coupled to the second line.

6. A power supply device comprising:
a first power supply circuit of a step-down type, configured to generate a first output voltage at a predetermined level from an alternating current (AC) voltage;
a second power supply circuit of a booster type, configured to generate a second output voltage from the AC voltage;
a control device coupled to the first power supply circuit and the second power supply circuit; and
a switching device having a first end and a second end, the first end receiving the AC voltage, the second end being coupled to the second power supply circuit, wherein
the first power supply circuit includes
a first rectifier circuit configured to rectify the AC voltage,
a first line coupled to the first rectifier circuit,
a second line on a ground side,
a switch coupled between the first line and the second line, and
a control circuit configured to control the switch to bring a level of the first output voltage to the predetermined level,

the first power supply circuit being free of an inductor interposed between the first line and the first rectifier circuit; and
the second power supply circuit includes
a second rectifier circuit coupled to the second end of the switching device, the second rectifier circuit being configured to rectify the AC voltage when the switching device is on, to thereby generate a second rectified voltage, and
an output circuit including
an inductor coupled to the second rectifier circuit, and
another switch configured to control current flowing through the inductor,

the output circuit being configured to output the second output voltage based on the second rectified voltage from the second rectifier circuit, wherein

the control device is configured to
receive a predetermined instruction,
receive the first output voltage as a power supply voltage thereof, and
control the switching device based on the predetermined instruction.

7. The power supply device according to claim 6 , wherein
the first power supply circuit is configured to supply first power to a first load of the first power supply circuit,
the second power supply circuit is configured to supply second power to a second load of the second power supply circuit, and
the first power is smaller than the second power.

Assignees

• Fuji Electric Co Ltd

Inventors

• Kobayashi Yoshinori
• Yamadaya Masayuki
• Shiroyama Hironobu
• Morimoto Toshimitsu

Classifications

• H02M1/08

  Circuits specially adapted for the generation of control voltages for semiconductor devices incorporated in static converters · CPC title

• H02M3/33571

  Half-bridge at primary side of an isolation transformer · CPC title

• H04N5/63

  Generation or supply of power specially adapted for television receivers · CPC title

• H02M7/05

  Capacitor coupled rectifiers · CPC title

• H02M1/36

  Means for starting or stopping converters · CPC title