Successive-Approximation Time-to-Digital Conversion Without External Timing
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Solution Overview
Problem
Existing methods for converting time intervals to digital words in monitoring and control systems require external timing signals, leading to energy inefficiency and complexity in timing operations.
Innovation Solution
A method and apparatus that map time intervals to differences in reference and signal times using a successive approximation scheme, where capacitors with varying capacitances are charged by current sources, eliminating the need for external timing signals and optimizing energy usage by controlling current intensities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If external timing signals are used for time interval conversion, then timing operations can be performed, but energy efficiency deteriorates and system complexity increases
Solution Approach 1:
The patent extracts and eliminates the external timing signal requirement from the conversion system. By using the input signal's own rising and falling edges to trigger and define the time interval measurement, the system no longer depends on external timing signals, thereby improving energy efficiency while maintaining timing operation capability
Solution Approach 2:
The conversion system performs self-timing by utilizing the input signal's own transitions (rising edge at t1, falling edge at t2) to automatically define and measure the time interval. This self-service mechanism eliminates the need for external timing control, reducing energy consumption and system complexity
2Reliability
If external timing signals are used for time interval conversion, then timing operations can be performed, but device complexity increases
Solution Approach 1:
The patent removes the external timing signal interface and associated control logic from the system. The conversion apparatus now only requires the input signal connections, eliminating complex timing signal routing, synchronization, and coordination mechanisms while maintaining accurate time interval measurement capability
Solution Approach 2:
The system automatically uses the input signal's own characteristics (rising edge t1, falling edge t2) to define the measurement interval, eliminating the need for external timing control logic, synchronizers, and coordination mechanisms, thereby simplifying the overall device architecture
3Productivity
If current intensities are controlled independently in the successive approximation scheme, then conversion speed improves, but control complexity increases
Solution Approach 1:
The patent implements dynamic control of current source intensities during the successive approximation process. The current intensities are adjusted based on the bit position being evaluated, allowing faster charging/discharging of capacitors for higher significance bits, thereby improving conversion speed through adaptive dynamic control
Solution Approach 2:
The conversion process is segmented into discrete bit evaluation steps, with each bit position having its own controlled current source. This segmentation allows independent optimization of current intensity for each bit, enabling faster overall conversion while maintaining manageable control through modular, step-by-step processing
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enhances energy efficiency by reducing power consumption between conversion cycles and simplifies control operations, allowing independent tuning of converter input ranges and reducing conversion time.
Implementation Method 1
a time interval is translated to a portion of electric charge through charging a sampling capacitor by a current source during the input time interval
Implementation Method 2
a set of capacitors of binary-weighted capacitances... Each capacitor corresponds to a bit in output digital word
Data Source
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Figure 2
AI summary
A method for conversion of a time interval to a digital word using a successive approximation scheme characterized in that the time interval (T) is mapped to a difference of a length of a reference time (RT) and a length of a signal time (ST). The reference time (RT) is generated from an instant (t1) when the beginning of the time interval (T) is detected, and the signal time (ST) is generated from an instant (t2) when the end of the time interval (T) is detected by the use the control module (CM). The generation of the reference time (RT) and the signal time (ST) is terminated at the same instant (t3). An apparatus for conversion of a time interval to a digital word using a successive approximation scheme comprises a control module (CM), two comparators (KR, KS), two current sources (IR, IS), two rails (R, S) and a set of capacitors (CS). The apparatus is characterized in that bottom plates of capacitors (Cn-1, Cn-2, ..., C1, C0) of the set of capacitors (CS) are connected to a ground of the circuit, and top plates of these capacitors are connected respectively to moving contacts of change-over switches (Sn-1, Sn-2, ..., S1, S0). First stationary contacts are connected to the signal rail (S), second stationary contacts are connected to the ground of the circuit, and third stationary contacts are connected to the reference rail (R).