Capacitor Charging Timing Circuit for Low-Power Precision Delay
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Solution Overview
Problem
Current time and capacitance measurement technologies require ultra-high frequency clocks and high power-consuming digital logic, leading to significant power consumption and circuit noise, making it difficult to achieve precise measurements without these constraints.
Innovation Solution
A system and method using a constant current source, current steering switch, capacitor, and analog-to-digital converter (ADC) to measure time and capacitance with low clock speed and low power consumption, allowing for high resolution measurements independent of the frequency accuracy of a time base reference and ADC resolution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If ultra-high frequency clocks and high power digital logic are used to measure short time periods, then measurement precision is improved, but power consumption and circuit noise increase
Solution Approach 1:
The patent replaces the mechanical/digital clock-based timing system with an analog capacitor charging system. Instead of using high-frequency digital clocks to measure time intervals, the invention uses a constant current source to charge a capacitor and measure the voltage change over time. This substitution of the measurement mechanism eliminates the need for ultra-high frequency clocks and high-power digital logic, thereby reducing power consumption and circuit noise while maintaining measurement precision.
Solution Approach 2:
The patent changes the fundamental parameter used for time measurement from frequency (clock cycles) to voltage (analog signal). By measuring the voltage across a capacitor that is being charged at a known constant rate, the system converts time intervals into voltage measurements. This parameter transformation allows for precise time measurement without requiring high-frequency digital signals, thus resolving the contradiction between measurement precision and power consumption.
2Measurement precision
If ultra-high frequency clocks are used to measure short time periods, then measurement precision is improved, but circuit noise increases
Solution Approach 1:
The patent replaces the high-frequency digital clock system with an analog capacitor charging system. The measurement mechanism transitions from detecting digital clock edges to measuring analog voltage changes. This substitution eliminates the source of high-frequency digital noise while maintaining the ability to measure short time periods with high precision through the analog measurement process.
Solution Approach 2:
The patent introduces a capacitor as an intermediary element between the time interval and the measurement system. The capacitor charges at a known rate during the time interval being measured, and the resulting voltage change serves as the measurement signal. This intermediary approach isolates the measurement process from high-frequency digital signals, thereby reducing circuit noise while preserving measurement precision.
3Use of energy by moving object
If low clock speed is used to reduce power consumption and noise, then power consumption and noise are reduced, but measurement precision deteriorates
Solution Approach 1:
The patent changes the measurement parameter from time-based (clock cycles at high frequency) to voltage-based (analog voltage measurement). By measuring the voltage across a capacitor that charges at a known constant rate, the system achieves precise time measurement independent of clock frequency. This parameter change allows low-clock-speed operation to maintain measurement precision while reducing power consumption and noise.
Solution Approach 2:
The patent substitutes the high-frequency digital timing mechanism with an analog capacitor charging mechanism. This substitution enables the system to operate at low clock speeds without sacrificing measurement precision, because the precision is derived from the analog voltage measurement and the known charging rate rather than from high-frequency digital signals.
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
Enables precise time and capacitance measurements with picoseconds resolution and extended dynamic range, reducing power consumption and circuit noise, while maintaining low power and low digital noise operations.
Implementation Method 1
a capacitor coupled to the current steering switch, the capacitor having a known value of capacitance, wherein a voltage on the capacitor increases substantially linearly in time when the current steering switch couples the constant current source to the capacitor
Data Source
AI summary
A time period of an event is determined by charging a known value capacitor from a constant current source during the event. The resultant voltage on the capacitor is proportional to the event time period and may be calculated from the resultant voltage and known capacitance value. Capacitance is measured by charging a capacitor from a constant current source during a known time period. The resultant voltage on the capacitor is proportional to the capacitance thereof and may be calculated from the resultant voltage and known time period. A long time period event may be measured by charging a first capacitor at the start of the event and a second capacitor at the end of the event, while counting clock times there between. Delay of an event is done by charging voltages on first and second capacitors at beginning and end of event, while comparing voltages thereon with a reference voltage.