Current Recycling Circuits for ADC Power Efficiency
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Solution Overview
Problem
Successive approximation analog-to-digital converters waste excessive power due to power absorption by impedance elements, which can be reduced by redirecting bias current to active circuits instead of dissipative resistors, thereby improving power efficiency.
Innovation Solution
A circuit and method that redirect a portion of the bias current from a signal buffer to an active circuit, which powers additional loads such as amplifiers, reducing power waste and maintaining overall power delivery to the switched capacitor circuit without increasing total power consumption, and using feedback and dummy loads to stabilize reference signals against fluctuations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If bias current is provided to impedance elements (resistors) to bias the signal buffer, then the signal buffer can provide reference signals to the switched capacitor circuit, but excessive power is absorbed and wasted by the impedance elements
Solution Approach 1:
The patent converts the harmful power dissipation in impedance elements into a beneficial resource by capturing the bias current that would otherwise be wasted and redirecting it to power active circuits such as amplifiers and other load circuits, thereby transforming energy loss into useful work
Solution Approach 2:
The patent recovers the bias current from the signal buffer that would normally be dissipated through impedance elements to ground, and redirects this recovered current to power active circuits, effectively reusing an otherwise discarded electrical resource
2Loss of energy
If power is reduced by removing impedance elements, then power efficiency improves, but the signal buffer cannot maintain proper biasing and reference signal generation
Solution Approach 1:
The patent eliminates the harmful power-dissipating impedance elements while converting the freed bias current into a beneficial resource that powers active circuits, simultaneously improving power efficiency and maintaining circuit functionality
Solution Approach 2:
The patent extracts and removes the impedance elements from the circuit configuration, taking out the source of power dissipation while preserving the essential biasing function through alternative current paths to active circuits
3Loss of energy
If bias current is redirected to active circuits, then power waste is reduced, but additional circuits require power that may not be available
Solution Approach 1:
The patent recovers the bias current that would otherwise be wasted through impedance elements and redirects it to power active circuits, effectively transferring available power from a dissipative path to a productive path without requiring additional power sources
Data Source
AI summary
Circuits and methods for current recycling in signal buffers for switched capacitor circuits are described. A signal buffer may be coupled to an impedance element, such as a resistor, configured to provide a desired reference voltage to the switched capacitor circuit. In some embodiments, a portion of the power absorbed by the impedance element may be recycled to power one or more additional circuit. Such additional circuit(s) may include active elements. In some embodiments, the switched capacitor circuit is part of an analog-to-digital converter. In some embodiments, the additional circuit(s) are also part of the analog-to-digital converter.