Power Supply Switch with Timer Circuit for Auto-Shutoff
Solution Overview
Problem
The frequent use of electrical appliances often leads to inattentive operation, resulting in household fires and excessive energy consumption due to the lack of auto-shutoff features in many appliances, which increases the risk of fires and energy wastage.
Innovation Solution
A power supply switch with a control circuit that includes a switch, current detection circuit, and timer circuit, allowing for automatic power removal from appliances after a set delay time, optionally featuring an AC-DC converter and Transient Voltage Suppression circuit to protect against voltage spikes, and a timer set switch for user-selectable delay times.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an auto-shutoff feature is included in appliances, then fire safety and energy conservation are improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The patent separates the auto-shutoff functionality from the appliance itself by using an external power supply switch. The timer circuit and control logic are isolated in a standalone device, while the appliance remains simple and unchanged. This segmentation allows the safety feature to be added without increasing appliance complexity.
Solution Approach 2:
The power supply switch acts as an intermediary device between the power source and the appliance. It contains the timer circuit and automatically interrupts power supply after a predetermined period, providing fire safety and energy conservation without requiring the appliance itself to be complex.
2Loss of energy
If an auto-shutoff feature is included in appliances, then energy consumption is reduced, but manufacturing cost increases
Solution Approach 1:
By separating the timer function into an external power supply switch, the appliance manufacturing process remains simple and cost-effective. The energy-saving feature is implemented in a separate, inexpensive device that can be used with any appliance.
Solution Approach 2:
The power supply switch is designed as an affordable, simple device that can be easily manufactured and distributed. Its low cost allows widespread adoption for energy conservation without significantly increasing overall system cost.
3Ease of operation
If the switch remains closed continuously, then ease of operation is improved, but fire hazard and energy wastage increase
Solution Approach 1:
The timer circuit is pre-set with a predetermined time period before the switch is operated. After the user closes the switch, the timer automatically counts down and opens the circuit without requiring user intervention, preventing fire hazards and energy wastage while maintaining ease of operation.
Solution Approach 2:
The power supply switch performs the shutoff function automatically based on the predetermined time setting. The device serves itself by automatically opening the circuit after the timer expires, eliminating the need for user monitoring or manual shutoff.
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 effectively reduces the risk of fires by automatically shutting off appliances and minimizes energy wastage by ensuring they are turned off after use, while also being cost-effective and adaptable to various electrical configurations.
Implementation Method 1
The AC-DC converter converts at least a portion of the power from the power source into a DC voltage which is then used to provide power to the circuitry included in the power supply switch
Implementation Method 2
The TVS circuit operates to remove, or otherwise suppress transient voltages, e.g., voltage spikes and the like, from the power supplied by the power source
Implementation Method 3
The current detection circuit senses a current passing through the switch to the appliance when the switch is in the closed position and outputs a signal indicative of the presence of the sensed current
Data Source
AI summary
A power supply switch comprising a power input assembly receiving power from a power source, a power output assembly connected to an appliance and a control circuit between the power input assembly and power output assembly. The control circuit comprises a switch having an open position and a closed position and being manually resettable by a user to the closed position, wherein power is supplied from the power input assembly to the power output assembly when the switch is in the closed position; a current detection circuit sensing a current passing from the power input assembly to the power output assembly, the current detection circuit outputting an activation signal indicative of the presence of the sensed current; and a timer circuit receiving the activation signal and automatically activating a timer in response, wherein the timer sends a signal to the switch causing the switch to move to the open position after a delay time.