Resistor-Multiplexed Wake-Up Circuit With Zero Standby Current
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Solution Overview
Problem
Existing circuits for activating electronic devices in vehicles face challenges in preventing power drainage during standby mode and efficiently activating microcontrollers to sense user inputs, often requiring multiple wires and leading to unwanted current draw.
Innovation Solution
A sensing circuit with a transistor and multiple switches connected to identifying resistors, which outputs activation signals efficiently, using a remote switch and control wire to minimize wire count and maintain zero standby current, allowing for economical and effective activation of microcontrollers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If existing circuits are used to activate electronic devices, then the devices can be activated, but power drainage occurs during standby mode
Solution Approach 1:
The patent extracts the activation function from the main controller and implements it in a separate sensing circuit that remains in standby mode. This sensing circuit only consumes minimal power to monitor for activation signals, while the main controller remains completely powered off during standby, eliminating power drainage while ensuring reliable activation when needed.
Solution Approach 2:
The sensing circuit performs preliminary monitoring of the control line for activation signals before the main controller is activated. This preliminary detection capability allows the system to remain in low-power standby mode while still being ready to respond immediately when an activation signal is detected on the control line.
2Adaptability or versatility
If multiple wires are used for switch connection, then switch inputs can be sensed, but wire count increases and complexity rises
Solution Approach 1:
The control line serves multiple functions: it carries both the activation signal and the switch input information. The sensing circuit detects switch states by measuring voltage levels or current flow through pull-up/pull-down resistors on this single control line, eliminating the need for separate wires for each switch while maintaining full sensing capability.
Solution Approach 2:
The patent merges the activation signal transmission and switch input sensing functions into a single control line. By combining these functions, the system reduces wire count and complexity while maintaining the ability to detect multiple switch states through voltage level detection or current measurement on the shared line.
3Reliability
If traditional activation circuits are used, then devices can be activated, but unwanted current draw occurs
Solution Approach 1:
The sensing circuit operates in a periodic or event-driven manner rather than continuously. It remains in a low-power state and only activates fully when an activation signal is detected on the control line. This periodic operation mode eliminates continuous current draw while ensuring the activation function is reliably performed when needed.
Solution Approach 2:
The sensing circuit acts as an intermediary between the control line and the main controller. It monitors the control line for activation signals using minimal power and only activates the main controller when needed, preventing unwanted current draw from flowing directly to the main controller during standby while maintaining reliable activation functionality.
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 circuit effectively prevents power drainage and efficiently activates microcontrollers to sense user inputs, ensuring zero standby current and enabling efficient control of electronic devices like wireless transmitters, while maintaining a compact single-wire interface.
Implementation Method 1
a first transistor configured to output an activation signal to the controller
Implementation Method 2
The transistor is configured to output an activation signal to the electrical device in response to an input received from at least one of the switches
Implementation Method 3
The first output node and the second output node are configured to output a characteristic voltage corresponding a ratio of each of the identifying resistors
Data Source
AI summary
A sensing circuit configured to activate a controller is disclosed. The circuit comprises a first transistor configured to output an activation signal to the controller and a plurality of switches in connection with a base of the transistor. Each of the switches is connected to an identifying resistor. A first output node and a second output node are in communication with the base of the transistor and each of the switches. The first output node and the second output node are separated across an additional identifying resistor. The first output node and the second output node are configured to output a characteristic voltage corresponding a ratio of each of the identifying resistors in response to an input received by one or more of the plurality of switches.