POWER SUPPLY APPARATUS

• US 20100195352A1
• Filed: 01/20/2010
• Published: 08/05/2010
• Est. Priority Date: 01/30/2009
• Status: Active Grant

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Murofushi, Mitsuhide
• Granted Patent: US 8,830,703 B2
• Time in Patent Office: Days
• US Class Current: 363/20
• CPC Class Codes: H02M 1/0032 Control circuits allowing low power mode operation, e.g. in standby mode
• CPC Class Codes: H02M 3/33561 having more than one ouput with independent control
• 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

The power supply apparatus includes a first control part that controls a switching operation of a first converter, a second control part that controls a switching operation of a second converter, a zero crossing circuit that outputs a zero crossing signal of a voltage to be input; and a voltage supply part that supplies a DC voltage obtained by rectifying an output of an auxiliary coil of a transformer of the first converter to the first control part, the second control part, and the zero crossing circuit. When the first converter stops, the supply of the DC voltage to the second control part and the zero crossing circuit is stopped to reduce a power consumption.

Claims

1. A power supply apparatus comprising:

a plurality of converters;

a first control part that controls a switching operation of a first converter among said plurality of converters;

a second control part that controls a switching operation of a second converter among said plurality of converters;

a zero crossing circuit that outputs a zero crossing signal at a zero crossing timing of a voltage to be input to said plurality of converters;

a voltage supply part that supplies a DC voltage obtained by rectifying an output of an auxiliary coil of a transformer of the first converter to the first control part, the second control part, and said zero crossing circuit; and

a switch part that changes over the supply of the DC voltage to the second control part and said zero crossing circuit,

wherein, when the first converter stops, the switch part stops the supply of the DC voltage to the second control part and the zero crossing.

2. A power supply apparatus according to claim 1, further comprising:

a voltage input part that rectifies the voltage to be input to said plurality of converters and inputs the rectified voltage to said zero crossing circuit; and

a voltage input selection part that selectively inputs a voltage from said voltage input part to said zero crossing circuit according to a switching operation of said switch part,

wherein the voltage input selection part inputs no voltage to said zero crossing circuit from the voltage input part while the supply of the DC voltage to the second control part and the zero crossing circuit stops.

3. A power supply apparatus according to claim 1, further comprising a voltage stop part that stops the supply of the DC voltage to the second control part and the zero crossing circuit at the same timing.

4. A power supply apparatus according to claim 1, wherein the switch part further stops the supply of the DC voltage to a switch part of said zero crossing circuit while the supply of the DC voltage to the second control part and the zero crossing circuit stops.

5. An image forming apparatus comprising

a power supply apparatus according to claim 1;

a fixing apparatus to which that an AC voltage input to said power supply apparatus is applied; and

a driving part to which a voltage from the first converter or the second converter is applied.