Amplifier Load Current Sensing via Internal Output Impedance
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Traditional load current sensing techniques require an additional shunt resistor, increasing component cost and complexity due to the need for a temperature-insensitive low-resistance shunt resistor, which complicates the sensing process.
Innovation Solution
Sensing the load current by obtaining a voltage drop across the internal impedance of the amplifier and computing the load current using this voltage drop and the internal impedance, eliminating the need for a shunt resistor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If an additional shunt resistor is placed in series with the load to sense load current, then load current can be measured, but component cost increases and device complexity increases
Solution Approach 1:
The patent extracts the sensing function from an external shunt resistor and relocates it to the amplifier's internal output impedance. By measuring the voltage across the amplifier's existing internal impedance rather than adding an external shunt resistor, the solution eliminates the need for additional sensing components while maintaining the ability to calculate load current through Ohm's law (I = V/Z).
Solution Approach 2:
The patent makes the amplifier's internal output impedance serve dual functions: its original function of limiting output current and its new function as a sensing element for load current measurement. This multi-functionality eliminates the need for dedicated sensing components, reducing both component count and system complexity.
2Ease of operation
If a shunt resistor with low resistance value is used to be non-intrusive to the amplifier and load, then signal transmission is not affected, but temperature sensitivity becomes a problem requiring extra handling effort
Solution Approach 1:
The patent leverages the amplifier's own internal output impedance characteristics to perform the sensing function. Since the internal impedance is already part of the amplifier's designed operating parameters, it inherently handles temperature variations without requiring external compensation circuits or additional handling, making the system self-sufficient for temperature management.
3Measurement precision
If an additional shunt resistor is added for load current sensing, then load current measurement is achieved, but component cost increases
Solution Approach 1:
The patent makes the amplifier's internal output impedance serve dual functions: its original function of limiting output current and its new function as a sensing element for load current measurement. This multi-functionality eliminates the need for dedicated sensing components, reducing both component count and system complexity.
4Measurement precision
If a shunt resistor is used for load current sensing, then current measurement is possible, but the shunt resistor requires constant resistance value maintenance despite temperature changes
Solution Approach 1:
The patent extracts the sensing function from an external shunt resistor and relocates it to the amplifier's internal output impedance. By measuring the voltage across the amplifier's existing internal impedance rather than adding an external shunt resistor, the solution eliminates the need for additional sensing components while maintaining the ability to calculate load current through Ohm's law (I = V/Z).
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 method simplifies and economizes load current sensing by eliminating the additional shunt resistor, reducing component costs and handling complexities, while maintaining accurate load current measurement.
Implementation Method 1
obtaining a voltage drop across internal impedance of the amplifier and computing the load current using the internal impedance and the voltage drop across the internal impedance
Data Source
AI summary
A system and method for sensing a load current that flows from an amplifier into a load of the amplifier involves obtaining a voltage drop across internal impedance of the amplifier and computing the load current using the internal impedance and the voltage drop across the internal impedance.