Power Sensing Circuitry Using PWM Modulation for Accuracy
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Solution Overview
Problem
Conventional power sensing techniques require complex circuitry, leading to high power consumption and poor speed performance, while struggling with accuracy and voltage rating constraints.
Innovation Solution
The technique involves converting source voltage into a pulse-width modulation (PWM) signal, allowing the duty cycle of the PWM signal to represent the source voltage, which modulates the current applied to a resistor to accurately sense power with reduced circuitry and power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional power sensing techniques using high precision discrete resistors and operational amplifiers are employed, then power sensing capability is achieved, but circuit complexity increases and power consumption rises
Solution Approach 1:
The patent extracts the multiplication function from complex analog circuitry and relocates it to a digital microprocessor. By using separate ADCs to convert voltage and current to digital values, then performing multiplication in software, the patent eliminates the need for complex analog multiplier circuits while maintaining power sensing accuracy.
Solution Approach 2:
The patent replaces the mechanical/analog multiplication operation (performed by operational amplifiers and resistors) with a digital computation approach. ADC converters transform analog signals to digital form, allowing the microprocessor to perform the multiplication function through software, thereby simplifying the hardware architecture.
2Measurement precision
If conventional power sensing circuitry with operational amplifiers is used, then power measurement is achieved, but power consumption increases
Solution Approach 1:
The patent removes the power-hungry operational amplifier multiplication circuitry and extracts the multiplication function to a digital domain. By using ADCs followed by digital multiplication in a microprocessor, the system achieves power sensing with significantly reduced power consumption compared to conventional analog approaches.
3Measurement precision
If high precision discrete resistors are used for current sensing, then current measurement accuracy improves, but voltage drop across the resistor increases
Solution Approach 1:
The patent changes the operating parameters of the sense resistor by using a low-ohm value resistor in combination with a high-resolution ADC. This allows accurate current measurement through voltage drop measurement across a minimal resistance, thereby reducing power loss while maintaining measurement precision through enhanced digital conversion capability.
4Measurement precision
If conventional analog multiplication circuitry is employed, then power sensing is achieved, but speed performance deteriorates
Solution Approach 1:
The patent replaces slow analog multiplication circuitry with fast digital ADC conversion followed by rapid microprocessor computation. This substitution of analog signal processing with digital processing significantly improves the response speed of power sensing while maintaining measurement accuracy.
Data Source
AI summary
Improved techniques for sensing and reporting power consumption from a single or multiple power supplies are disclosed. The disclosed techniques comprise integrated circuit solutions for sensing power. In some embodiments, an integrated circuit comprises circuitry for converting source voltage into a pulse-width modulation (PWM) signal and circuitry for modulating the PWM signal with a current sense signal to determine sensed power.