Switching Power Supply Transformer Oscillation Control

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Solution Overview

Problem

The existing switching power supply devices consume unnecessary power in standby mode due to continuous power supply to internal circuits, and require a delay circuit for startup, which complicates the circuit structure.

Innovation Solution

The power supply system stops transformer oscillation in output stop mode, uses a control device to supply power to the switch control unit for switching control, and employs a photoelectric cell for power in standby mode, eliminating the need for a delay circuit and simplifying the structure by sharing input ports for oscillation stop and restart circuits.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If power is supplied to the internal circuit of the IC in standby mode, then the IC can quickly respond when power is turned on, but unnecessary power consumption occurs

Engineering Contradiction:
Improveresponse speedVSAvoidpower consumption
Core Design Contradiction:
SpeedVSUse of energy by moving object

Solution Approach 1:

The patent extracts the unnecessary power consumption by stopping the oscillation of the transformer in standby mode. The IC enters a low-power state where the transformer oscillation is halted, eliminating the main source of power consumption while maintaining the ability to quickly restart when needed.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent implements periodic action by controlling the transformer oscillation to start and stop based on operational needs. In standby mode, oscillation is stopped; when power is needed, oscillation resumes. This periodic on/off control optimizes both power consumption and response capability.

Inventive Principle:
Principle #19Periodic action

2Reliability

If a delay circuit is added to set the input port level to low during startup, then switching control can start properly, but the circuit structure becomes complicated

Engineering Contradiction:
Improvestartup reliabilityVSAvoidcircuit structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent removes the delay circuit from the system by changing the control logic. Instead of using a delay circuit to set the input port level, the system directly controls the switching element based on the input signal, eliminating the unnecessary component while maintaining reliable startup.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent inverts the conventional approach by not requiring the input port level to change to a specific level for startup. Instead, the switching control starts based on the direct input signal level, reversing the traditional delay-based initialization method.

Inventive Principle:
Principle #13The other way round (Inversion)

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 reduces power consumption, simplifies the circuit structure, and prevents errors in operation by inhibiting false restarts, while maintaining a charging state for a longer duration.

Implementation Method 1

the control device may include a photoelectric cell that converts optical energy into power and serves as a power supply for the control device in the output stop mode

Methodology Applied
Scientific EffectPhotoelectric conversion: Photovoltaic Effect

Data Source

PatentEP2451067B1Power supply system and image forming apparatus
Publication Date: 2020.02.26 BROTHER KOGYO KK
  • EP2451067B1 patent drawingFigure 1
  • EP2451067B1 patent drawingFigure 2
  • EP2451067B1 patent drawingFigure 3

AI summary

A power supply system includes: a switching power supply (10); and a control device, wherein the switching power supply (10) includes: a transformer (23); a semiconductor switching element (25); a switch control unit (50); and a rectifying/smoothing circuit (21), the switch control unit is supplied with power from the main power supply (15), starts to control the switching of the semiconductor switching element (25), and oscillates a primary side (N1) of the transformer (23) to induce a voltage on the secondary side (N2) of the transformer (23), the control device outputs a control pulse signal to the switch control unit (50) to stop the oscillation of the transformer (23), thereby changing the mode of the switching power supply to an output stop mode, in an output mode in which the switching power supply smoothes the voltage induced on the secondary side and outputs the smoothed voltage.