Input Supply Bias Circuit for Voltage Tracking With Low Quiescent Current
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Solution Overview
Problem
Existing input supply circuits face challenges in tracking external supply voltages, switching between input threshold and supply voltage ranges, and maintaining low quiescent current draw for reduced power consumption.
Innovation Solution
The input supply circuit incorporates a bias circuit with semiconductor devices, resistors, and capacitors to define a voltage threshold based on input and output signals, and a multiplexer to control signal passage, allowing it to track external supply voltages and switch between voltage ranges while minimizing static current draw.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a traditional voltage converter is used to track external supply voltage, then the voltage tracking capability is improved, but the quiescent current draw increases
Solution Approach 1:
The patent extracts the voltage tracking function from a traditional voltage converter by using a dedicated bias circuit that generates a voltage threshold tracking an external supply voltage. This separation allows the tracking function to operate with minimal quiescent current while the main circuit remains efficient.
Solution Approach 2:
The patent changes the operating parameters by using a bias circuit with transistors and capacitors that can dynamically adjust the voltage threshold parameter to track external supply voltage changes, achieving adaptability without the continuous power consumption of traditional converters.
2Adaptability or versatility
If a fixed input threshold voltage is used, then the circuit design is simplified, but the ability to switch between input threshold voltage and supply voltage range is lost
Solution Approach 1:
The patent implements a dynamic voltage threshold that can switch between tracking mode and fixed mode. The bias circuit dynamically adjusts the threshold voltage based on control signals, allowing the system to adapt between different operating modes without requiring multiple fixed circuits.
Solution Approach 2:
The bias circuit serves multiple functions: it generates the voltage threshold for normal operation, tracks external supply voltage when needed, and can be controlled to provide a fixed threshold. This multi-functionality achieves voltage range switching capability within a unified circuit structure.
3Measurement precision
If the bias circuit continuously adjusts the voltage threshold to track external supply voltage, then the voltage tracking precision is improved, but the power consumption increases
Solution Approach 1:
The bias circuit uses periodic updating of the voltage threshold through controlled charging and discharging of capacitors. Instead of continuous adjustment, the circuit updates the threshold at appropriate moments, maintaining tracking precision while minimizing continuous power consumption.
Solution Approach 2:
The patent implements feedback mechanisms where the bias circuit monitors the external supply voltage and adjusts the threshold accordingly. The feedback ensures accurate tracking while the circuit is designed to minimize energy loss in the feedback path, achieving precision with reduced power consumption.
Data Source
AI summary
Embodiments of input supply circuits and methods for operating an input supply circuit are described. In one embodiment, an input supply circuit includes a bias circuit configured to define a voltage threshold in response to an input signal, and an input buffer configured to generate an output signal in response to the voltage threshold. Other embodiments are also described.