Power Supply Standby Circuit Using Capacitor Segmentation

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Solution Overview

Problem

Existing power supply systems in power saving mode continue to consume power unnecessarily due to the need for oscillation of the output transformer to charge secondary batteries or electric double-layer capacitors, which is not efficient for long standby periods.

Innovation Solution

The system rectifies and smooths AC voltage applied to both capacitors, allowing the low-capacity power supply circuit to provide power without restarting the oscillation of the switching power supply in power saving mode, thus eliminating the need for transformer oscillation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the output transformer oscillates to charge the secondary battery or electric double-layer capacitor in standby mode, then the control unit can be powered, but power is wastefully consumed

Engineering Contradiction:
Improvepower supply to control unitVSAvoidpower consumption in standby mode
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

The power supply system is divided into two independent paths: a main power supply path for normal operation and a standby power supply path using a small capacitor for power-saving mode. This segmentation allows the system to use different power sources appropriate for different operational states, eliminating the need to oscillate the main transformer during standby.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention changes the power supply parameter from using the main transformer output (24V) to using a small capacitor (C3) specifically designed for standby operation. This parameter change enables the system to operate with minimal power consumption during standby while still providing sufficient power to the control unit.

Inventive Principle:
Principle #35Parameter changes

2Loss of energy

If the output transformer stops oscillation in standby mode to save power, then power consumption is reduced, but the control unit cannot be powered

Engineering Contradiction:
Improvepower consumption in standby modeVSAvoidpower supply to control unit
Core Design Contradiction:
Loss of energyVSReliability

Solution Approach 1:

A small capacitor (C3) is introduced as an intermediary power storage element specifically for standby operation. This capacitor acts as a mediator that provides power to the control unit during standby mode without requiring the main transformer to oscillate, thus resolving the contradiction between power consumption and power supply reliability.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The capacitor C3 is charged in advance during normal operation when the transformer is oscillating. This preliminary charging action ensures that sufficient energy is stored in the capacitor before standby mode begins, allowing the control unit to be powered during standby without requiring continuous transformer oscillation.

Inventive Principle:
Principle #10Preliminary action

3Quantity of substance

If the transformer primarily oscillates to charge the electric double-layer capacitor during long standby periods, then the capacitor can be charged, but power consumption increases

Engineering Contradiction:
Improvecharge in electric double-layer capacitorVSAvoidpower consumption during charging
Core Design Contradiction:
Quantity of substanceVSLoss of energy

Solution Approach 1:

Instead of using the full transformer capacity to charge the capacitor, the invention uses only a small portion of the power requirement by employing a dedicated small capacitor (C3) that can be charged with minimal current. This partial action approach provides sufficient charge for standby operation without the excessive power consumption of full transformer oscillation.

Inventive Principle:
Principle #16Partial or excessive action

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This approach significantly reduces power consumption in power saving mode by eliminating the need for transformer oscillation, allowing for further power savings in the power supply system.

Implementation Method 1

a rectifying circuit (31) electrically connected between a second electrode C1p2 of the first capacitor and a second electrode C2p2 of the second capacitor, and rectifying an AC voltage Vac applied to both the first and second capacitors

Methodology Applied
Scientific EffectRectification: Diode

Implementation Method 2

a smoothing circuit (32) electrically connected to the rectifying circuit (31), and smoothing a voltage rectified by the rectifying circuit (31)

Methodology Applied
Scientific EffectCapacitive smoothing: Capacitance

Data Source

PatentEP2552004B1Power supply system with low power standby supply for control unit
Publication Date: 2019.05.22 BROTHER KOGYO KK
  • EP2552004B1 patent drawingFigure 1
  • EP2552004B1 patent drawingFigure 2
  • EP2552004B1 patent drawingFigure 3~4

AI summary

A power supply system (100) includes: a switching power supply (21, 20), which rectifies and smoothes an AC voltage of an AC power supply to generate a first DC voltage in a normal mode; a control unit (51), which controls the switching power supply to switch between the normal mode and a power saving mode; and a low-capacity power supply circuit, which supplies power to the control unit in the power saving mode, and which includes: a first capacitor (C1), which includes a first electrode connected to one end of the AC power supply, and a second electrode; a second capacitor (C2), which includes a first electrode connected to the other end of the AC power supply, and a second electrode; a rectifying circuit (31), which rectify an AC voltage applied to both capacitors; and a smoothing circuit (32), which smoothes the rectified AC voltage to generate a smooth voltage.