Switching power source device

• US 20030151928A1
• Filed: 02/19/2003
• Published: 08/14/2003
• Est. Priority Date: 01/19/2001
• Status: Active Grant

• Current Assignee: Sony Corporation (Sony Group Corp.)
• Original Assignee: Sony Corporation (Sony Group Corp.)
• Inventors: Okada, Masami, Kobori, Katsumi
• Granted Patent: US 6,816,395 B2
• Time in Patent Office: Days
• US Class Current: 363/21.01
• CPC Class Codes: H02M 1/0032 Control circuits allowing low power mode operation, e.g. in standby mode
• CPC Class Codes: H02M 3/28 using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac
• CPC Class Codes: H02M 3/33507 with automatic control of the output voltage or current, e.g. flyback converters H02M3/33561, H02M3/33569 take precedence
• CPC Class Codes: H02M 3/33523 with galvanic isolation between input and output of both the power stage and the feedback loop
• 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 present invention provides a switching power supply which includes a main rectifying and smoothing circuit (40) and a secondary rectifying and smoothing circuit (50) for rectifying and smoothing an output obtained at a secondary coil (22) of a converter transformer (20) whose primary coil (21) is supplied with a switching output from a switching element (30) which switches a direct input. A error detecting circuit (60), which is driven by a secondary rectified and smoothed output from the secondary rectifying and smoothing circuit (50), detects a main rectified and smoothed output from the main rectifying and smoothing circuit (40) to be supplied to loads so as to control the switching operation of the switching element (30) by the PWM controlling circuit (80) so that the main rectified and smoothed output is caused to be a predetermined state, and compares the voltage of the secondary rectified and smoothed output with the voltage of the main rectified and smoothed output so as to change the operation state of the PWM controlling circuit (80) to the standby mode in case the voltage of the secondary rectified and smoothed output declines to come below the voltage of the main rectified and smoothed output by a predetermined value.

Claims

1. A switching power supply, comprising:

switching means for switching a direct input;

switching control means for controlling the switching operation of the switching means;

a converter transformer whose primary winding is supplied with a switching output from the switching means;

main rectifying and smoothing means and secondary rectifying and smoothing means for rectifying and smoothing an output obtained at a secondary winding of the converter transformer; and

error detection means, which is driven by a secondary rectified and smoothed output from the secondary rectifying and smoothing means, for detecting a main rectified and smoothed output from the main rectifying and smoothing means to be supplied to loads so as to control the switching operation of the switching means by the switching control means so that the main rectified and smoothed output is caused to be a predetermined state, and for comparing the voltage of the secondary rectified and smoothed output with the voltage of the main rectified and smoothed output so as to change the operation state of the switching control means to the standby mode in case the voltage of the secondary rectified and smoothed output declines to come below the voltage of the main rectified and smoothed output by a predetermined value.