Discharging Circuit Variable Resistance for Standby Power Reduction
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Solution Overview
Problem
Existing discharging circuits in electronic apparatuses consume significant power during standby mode and may mis-detect zero-crossing or fail to quickly discharge residual charges due to high power consumption and sensitivity to noise in commercial AC power supplies.
Innovation Solution
A discharging circuit with a two-way switch element and RC integrating circuit that sets a higher resistance value for the discharge resistance, allowing quick discharge of residual charges and reducing power consumption by using a bidirectional thyristor or transistor to control the discharge process, effectively filtering noise and ensuring accurate detection of AC plug removal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a discharge resistance is provided in parallel with the X-capacitor to discharge residual charges quickly, then the discharging speed is improved, but the power consumption increases significantly during standby mode
Solution Approach 1:
The patent applies dynamics by making the discharge resistance value variable rather than fixed. The resistance is dynamically adjusted based on the operating state: during normal operation, a low resistance value enables quick discharge of residual charges, while during standby mode, a high resistance value minimizes power consumption. This is achieved through control circuitry that switches between different resistance values or adjusts the resistance continuously based on detected operating conditions.
Solution Approach 2:
The patent changes the resistance parameter of the discharge resistance based on the operating state of the electronic apparatus. By detecting whether the apparatus is in normal operation or standby mode, the system adjusts the resistance value accordingly - using a low resistance value (e.g., 1 MΩ or lower) during normal operation for quick discharge, and a high resistance value (e.g., 10 MΩ or higher) during standby mode to reduce power consumption to negligible levels.
2Use of energy by moving object
If a zero-crossing detecting circuit is used instead of a discharging circuit to reduce power consumption, then the power consumption is reduced, but the circuit may mis-detect zero-crossing or fail to quickly discharge residual charges due to noise sensitivity
Solution Approach 1:
The patent segments the functionality by separating the zero-crossing detection function from the discharge control function. Instead of relying on the zero-crossing detecting circuit for both purposes, the system uses a dedicated detection circuit that is less sensitive to noise for detecting AC plug removal, and separately controls the discharge resistance to ensure reliable residual charge discharge. This segmentation allows each function to be optimized independently.
Solution Approach 2:
The patent introduces an intermediary detection circuit that acts as a mediator between the AC power supply and the control system. This intermediary circuit is specifically designed to detect AC plug removal with high reliability by filtering out noise and providing a clean detection signal to the control circuitry, which then appropriately controls the discharge resistance. The intermediary serves as a buffer that prevents noise from directly affecting the control decisions.
3Loss of time
If the discharge resistance value is set low to ensure quick discharge within one second, then the discharging speed is improved, but the power consumption during standby mode becomes significant
Solution Approach 1:
The patent applies dynamics by making the discharge resistance value variable rather than fixed. The resistance is dynamically adjusted based on the operating state: during normal operation, a low resistance value enables quick discharge of residual charges, while during standby mode, a high resistance value minimizes power consumption. This is achieved through control circuitry that switches between different resistance values or adjusts the resistance continuously based on detected operating conditions.
Solution Approach 2:
The patent implements periodic monitoring of the operating state to determine when to switch between different resistance values. The control system periodically detects whether the electronic apparatus is in normal operation or standby mode and adjusts the discharge resistance accordingly. This periodic action ensures that the system maintains optimal performance for the current operating phase while minimizing energy waste during standby periods.
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
The solution reduces power consumption by approximately 50.3 mW compared to conventional configurations while maintaining high tolerance against noise interference, ensuring quick and accurate discharge of residual charges within one second after AC plug removal.
Implementation Method 1
an RC integrating circuit which includes a resistance and a capacitor serially connected, the voltage across the capacitor increases with the passage of time when voltage of a commercial AC power supply is input
Implementation Method 2
a two-way switch element which allows bidirectional flow of current and has a control terminal, the bidirectional thyristor is turned on when a voltage across the capacitor exceeds a threshold value
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
A discharging circuit (100) includes a filter unit (102) connected between the input lines of a commercial AC power supply, a switch (170) whose operations are controlled by the filter unit and a discharging unit (120) which discharges voltage of a capacitance element (141) when the switch unit is turned on.