Current Sense Rectifier Circuit Using Merged Amplification
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Solution Overview
Problem
Conventional current feedback circuitry that uses traditional full wave rectifiers and cascaded amplifiers is costly and prone to error magnification, while half wave rectifiers lose half of the signal and have longer response times due to larger output filters.
Innovation Solution
A current sense rectifier circuit utilizing negative and positive half-wave circuits with single diodes and resistances, combined with a closed-loop amplifier, to achieve full wave rectification, gain, attenuation, and filtering with reduced component count, providing thermal stability and linearity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a traditional full wave rectifier and pair of cascaded amplifiers are used, then full wave rectification and signal amplification are achieved, but device complexity and cost increase due to requiring two amplifiers
Solution Approach 1:
The patent combines the rectification and amplification functions into a single operational amplifier by using its differential input terminals. The positive half-wave circuit connects to the non-inverting terminal while the negative half-wave circuit connects to the inverting terminal, allowing one amplifier to perform both full-wave rectification and signal amplification simultaneously, thereby reducing component count and system complexity
2Power
If a traditional full wave rectifier and cascaded amplifiers are used, then signal amplification is achieved, but error magnification occurs as errors from the first stage are compounded by the second stage
Solution Approach 1:
By merging rectification and amplification into a single operational amplifier stage, the patent eliminates the error propagation issue inherent in cascaded amplifier configurations. The single-stage design ensures that errors are not magnified multiple times through successive amplification stages, thereby improving measurement precision while maintaining full-wave rectification accuracy
3Device complexity
If a half wave rectifier is used, then device complexity is reduced, but signal loss occurs as half of the sensed signal is discarded
Solution Approach 1:
The patent uses the differential input capability of the operational amplifier to simultaneously process both positive and negative half-waves from separate half-wave circuits. This allows full-wave rectification to be achieved with a simple single-stage circuit, maintaining circuit simplicity while preventing any signal loss that would occur with traditional half-wave rectification
4Device complexity
If a half wave rectifier with larger output filter is used, then device complexity is reduced, but response time increases due to the larger time constant required
Solution Approach 1:
By combining full-wave rectification and amplification in a single operational amplifier stage, the patent produces a cleaner rectified output with less ripple. This eliminates the need for large output filters that would be required with half-wave rectification, thereby maintaining simple circuit structure while achieving fast response times through the inherent filtering effect of the full-wave rectification process
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
The solution significantly reduces component costs, minimizes error, and maintains signal integrity by using fewer components while achieving efficient full wave rectification and amplification, offering improved thermal stability and linearity.
Implementation Method 1
The negative half-wave circuit includes a single diode in connection with a resistance. The positive half-wave circuit includes a single diode in connection with a resistance
Implementation Method 2
A closed-loop amplifier generates the DC voltage output signal as a function of the first and second voltage input signals. The closed-loop amplifier inverts the first input signal, and the output terminal generates a direct current (DC) voltage output signal as a function of the inverted first input signal and the second input signal
Implementation Method 3
The negative half-wave circuit includes a single diode in connection with a resistance. The positive half-wave circuit includes a single diode in connection with a resistance
Data Source
AI summary
A current sense rectifier circuit comprises an assembly input terminal for receiving a current input signal having an alternating current (AC) waveform. A negative half-wave circuit generates a first input signal representative of negative portions of the current input signal. A positive half-wave circuit generates a second input signal representative of positive portions of the current input signal. The negative and positive half-wave circuits each include a single diode and a resistance. A closed-loop amplifier has an inverting input terminal connected to the negative half-wave circuit, and a non-inverting input terminal connected to the positive half-wave circuit. The closed-loop amplifier inverts the first input signal and provides a DC voltage output signal via an output terminal that is a function of the inverted first input signal and the second input signal. An assembly output terminal is connected to the output terminal to receive the DC voltage output signal therefrom.