Sensor Headroom Control Circuit for Power-Noise Trade-off
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Solution Overview
Problem
Portable electronic devices equipped with sensors face a trade-off between power consumption and noise performance, as reducing power consumption often increases sensor noise, and typically consume more power than necessary due to providing larger headroom than required.
Innovation Solution
A sensor headroom control circuit that adaptively selects a headroom state based on the detected signal level, comprising a front end analog circuit, digital compensation circuit, and headroom state selection circuit, which adjusts gain or bias to reduce power consumption while maintaining signal quality, and interpolates sensor output during state transitions to minimize glitches.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If power consumption is reduced, then battery life is extended, but sensor noise performance deteriorates
Solution Approach 1:
The patent implements dynamic headroom adjustment by switching between multiple headroom states (first headroom state with lower power consumption and second headroom state with higher power consumption) based on detected signal levels. The system transitions from a static headroom configuration to a dynamic one where operational parameters are continuously adapted to current signal conditions, thereby optimizing the trade-off between power consumption and noise performance in real-time.
Solution Approach 2:
The system changes operational parameters (headroom state, gain settings, bias current) based on detected signal levels. When signal levels are low, the system switches to a first headroom state with lower power consumption; when signal levels are high, it switches to a second headroom state with higher power consumption but better noise performance. This parameter adaptation resolves the contradiction by matching resource allocation to actual operational needs.
2Adaptability or versatility
If larger headroom is provided, then signal range is increased, but power consumption increases
Solution Approach 1:
The patent employs dynamic headroom switching between at least two headroom states based on detected signal levels. The system monitors incoming signal levels and switches to a larger headroom state only when necessary (when signal levels exceed a threshold), otherwise operating in a smaller, lower-power headroom state. This dynamic adaptation allows the system to maintain signal range capability while minimizing power consumption during normal operation.
Solution Approach 2:
The system dynamically changes the headroom parameter based on signal level detection. When signal levels are within a normal range, the system operates with a first headroom setting that consumes less power. When signal levels approach or exceed the headroom boundary, the system switches to a second headroom state with larger signal range capability. This conditional parameter change resolves the contradiction between signal range and power consumption.
3Use of energy by moving object
If headroom state switching is implemented, then power consumption is optimized, but signal continuity may be disrupted
Solution Approach 1:
The patent implements preliminary interpolation of sensor output values during headroom state transitions. Before and during the switching event, the system calculates interpolated values based on previous and expected signal levels, ensuring that no gaps or discontinuities occur in the output signal. This preliminary preparation of transition data maintains signal continuity while allowing headroom state changes to occur.
Solution Approach 2:
The system uses interpolation as an intermediary mechanism during headroom state transitions. Rather than directly switching between discrete headroom states (which would cause discontinuities), the system introduces interpolated signal values as a bridge during the transition period. This intermediary approach smooths the transition and maintains signal continuity while still enabling power consumption optimization through headroom state switching.
Data Source
AI summary
A sensor headroom control circuit includes a front end analog circuit, a digital compensation circuit, and a headroom state selection circuit. The front end analog circuit has configurable headroom and is configured to receive a sensor input signal and output a sensor digital signal. The digital compensation circuit is configured to adjust the sensor digital signal to compensate for an active headroom state of the front end analog circuit and produce a compensated sensor signal. The headroom state selection circuit is configured to select the active headroom state of the front end analog circuit responsive to a detected level of the compensated sensor signal.