ADC Bias Current Control for Low-Power Ready-State Sampling
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Solution Overview
Problem
Analog to digital converters in battery-powered devices consume significant power even when not actively used, leading to battery drain and undesirable delays when they need to be turned back on, due to high startup times and constant power consumption.
Innovation Solution
A system that controls bias current to analog to digital converters by providing an idle bias current when not in use, which is sufficient to keep the converter operational but reduces power consumption to approximately 25% of the operating current, allowing for quick transition to operating mode when needed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the analog to digital converter is left on and ready for conversion, then immediate conversion is possible, but significant battery power is consumed
Solution Approach 1:
The patent applies dynamics by making the bias current adjustable between two states: a first bias current when the converter is active and a second bias current when inactive. This dynamic adjustment allows the system to optimize between power consumption and conversion readiness based on operational state, resolving the contradiction between immediate availability and battery conservation.
2Use of energy by moving object
If the analog to digital converter is turned off to conserve power, then battery power is saved, but delays occur when conversion is needed
Solution Approach 1:
The patent applies preliminary action by maintaining a non-zero second bias current when the converter is considered inactive. This preliminary current keeps the converter in a partially ready state, so when conversion is needed, the startup time is minimized while still achieving significant power savings compared to maintaining full operational current continuously.
3Use of energy by moving object
If the analog to digital converter is turned off, then power consumption is reduced, but the converter cannot be used immediately after turning back on
Solution Approach 1:
The patent uses dynamic bias current adjustment to maintain conversion availability while reducing power consumption. By switching between first and second bias currents based on operational state, the system ensures the converter can be quickly reactivated without significant startup delays, thereby maintaining productivity while achieving power savings.
Data Source
AI summary
A converter includes an analog to digital converter having a bias current input, a control input, and an analog input to provide a digital output as a function of the analog input. A bias module is coupled to the bias current input to provide bias current to the analog to digital converter. A controller is coupled to the bias module and to the control input of the analog to digital converter. The controller controls the analog to digital converter to sample an analog input and controls the bias module to provide an operating bias current during sampling of the analog input and an idle bias current when not sampling the analog input.