Sensitivity Switchable Detection Circuit Gain Transition
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Solution Overview
Problem
Sensitivity switchable detection circuits experience sudden changes in detected signals during gain switching operations due to gain errors, leading to uncomfortable motor torque changes in applications like electric power steering, which existing solutions attempt to mitigate by reducing manufacturing tolerances and temperature variations but result in increased costs and reduced yield.
Innovation Solution
A sensitivity switchable detection circuit with a first and second detection circuit and an output switching circuit that transitions through a middle gain region, using a weighting function to gradually switch between high and low gain regions, thereby minimizing sudden signal changes and maintaining cost-effectiveness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If gain switching is performed between high gain region and low gain region, then dynamic range is extended, but sudden signal changes occur due to gain errors
Solution Approach 1:
A middle gain region is introduced as an intermediary between the high gain region and low gain region. During transition, the detection circuit passes through this intermediate state where gain is gradually adjusted, preventing abrupt signal changes. This mediator region acts as a buffer that smooths the transition and eliminates sudden jumps caused by direct switching between disparate gain states.
Solution Approach 2:
The gain switching mechanism is made dynamic by continuously adjusting the gain parameter during transition rather than making discrete jumps. The detection circuit dynamically adapts its gain setting based on the input signal amplitude, smoothly transitioning through the middle gain region. This dynamic adjustment ensures signal continuity while maintaining the ability to switch between high and low gain states for extended dynamic range.
2Manufacturing precision
If manufacturing tolerances and temperature variations are reduced, then gain errors are minimized, but production cost increases and yield decreases
Solution Approach 1:
Instead of relying on tight manufacturing tolerances to minimize gain errors, the invention changes the operational parameter approach by introducing a middle gain region and dynamic gain adjustment. This allows the system to compensate for gain errors through software-controlled gain modulation rather than requiring precision hardware manufacturing. The parameter change from static fixed gain to dynamic adjustable gain enables cost-effective error compensation.
Solution Approach 2:
The invention creates a virtual copy of the gain adjustment mechanism through software control. Rather than physically adjusting circuit components to achieve precise gain matching, the system uses digital signal processing to simulate and correct gain transitions. This software-based approach replicates the effect of precision manufacturing without the associated costs and yield issues.
Data Source
AI summary
A sensitivity switchable detection circuit includes a high gain circuit for outputting a first signal, a low gain circuit for outputting a second signal, and an output switching circuit for switching between the first signal and the second signal. When the first signal is smaller than a lower limit, the first signal determines a detected signal. When the second signal is larger than an upper limit, the second signal determines the detected signal. When the first signal is larger than the lower limit and the second signal is lower than the upper limit, a weighting function that uses the first signal and the second signal as input variables determines the detected signal.