FET Power Cut-Off Circuit for Low-Reactive Standby Electronics
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Solution Overview
Problem
Existing electronic devices face increased reactive power consumption when switching to a burst mode to reduce standby power, leading to potential energy waste.
Innovation Solution
An electronic device comprising a power converter, a state detecting unit, a driving power supply unit, a power cut-off unit with a field effect transistor (FET), and a control unit that cuts off DC power when the user device is in a designated off-state, minimizing waste by switching the FET to a low state.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the user device switches to burst mode to reduce standby power, then standby power is reduced to 1W or less, but reactive power consumption increases
Solution Approach 1:
The patent extracts the power cut-off function from the main power supply system by introducing a separate power cut-off unit with FET and diode that operates independently from the burst mode control. This allows the burst mode to continue reducing standby power while the extracted cut-off unit eliminates reactive power consumption by completely disconnecting power to the driving power supply unit when the device is turned off.
Solution Approach 2:
The patent introduces a power cut-off unit as an intermediary component between the power converter and the driving power supply unit. This intermediary uses a FET and diode to control power flow, enabling the system to achieve both low standby power (through burst mode) and low reactive power consumption (through the cut-off unit's complete disconnection capability).
2Loss of energy
If the electronic device completely cuts off power to reduce reactive power, then reactive power consumption is minimized, but the device cannot detect state changes or respond to user input
Solution Approach 1:
The patent segments the power supply system into multiple independent parts: the power converter, the driving power supply unit, and the state detecting unit. The power cut-off unit selectively cuts off power to the driving power supply unit while leaving the state detecting unit operational, enabling the system to maintain state detection capability even when reactive power consumption is minimized.
Solution Approach 2:
The patent applies different power states to different parts of the system: the driving power supply unit receives complete power cut-off to minimize reactive power consumption, while the state detecting unit continues to receive power to maintain detection capability. This local differentiation of power supply quality allows the system to simultaneously achieve low energy loss and high reliability.
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
Effectively reduces wasted power by cutting off DC power to the driving power supply unit when the user device is turned off, minimizing energy consumption.
Implementation Method 1
a first photo coupler and a first diode electrically connected with the first photo coupler, configured to detect a state of a user device
Implementation Method 2
a power cut-off unit, comprising a first field effect transistor (FET), configured to cut off the DC power provided to the driving power supply unit
Data Source
AI summary
An electronic device according to various embodiments may comprise a power converter configured to generate DC(direct current) power based on power obtained from outside, a state detecting unit, comprising a first photo coupler and a first diode electrically connected with the first photo coupler, configured to detect a state of a user device that comprises the electronic device or is electrically connected with the electronic device, a driving power supply unit configured to supply driving power for the user device based on the DC power, a power cut-off unit, comprising a first field effect transistor (FET), configured to cut off the DC power provided to the driving power supply unit according to the state of the user device, a control unit electrically connected with the state detecting unit.