CMOS Detector Circuit for Temperature-Stable AC Power Sensing
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Solution Overview
Problem
Existing detector circuits in wireless communication apparatuses face challenges in accurately detecting AC signal power due to temperature variations, as the output voltage varies significantly with temperature changes, making it difficult to maintain consistent detection results.
Innovation Solution
A detector circuit design incorporating two CMOS inverters with opposite temperature characteristics, coupled with capacitors and resistors, where the output nodes of the inverters are connected via resistors with calculated resistances to stabilize the output voltage, reducing temperature-induced variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a diode-based detector circuit is used to detect AC signal power, then the circuit can perform power detection, but the output voltage varies significantly with temperature changes, reducing measurement accuracy
Solution Approach 1:
The patent changes the operating parameters of the detector circuit by using two different bias voltages (first bias voltage and second bias voltage) applied to the diode through separate voltage sources. This allows the circuit to operate at different bias points, enabling temperature compensation by adjusting the detection characteristics to counteract temperature-induced variations in output voltage.
Solution Approach 2:
The patent implements a feedback mechanism where the output voltage is monitored and used to control variable resistors that adjust the bias voltages. The control unit receives the output voltage signal and modifies the bias voltages accordingly, creating a closed-loop system that compensates for temperature variations and maintains stable power detection accuracy.
2Measurement precision
If temperature compensation is implemented in the detector circuit, then measurement accuracy improves, but the device complexity increases due to additional components
Solution Approach 1:
The patent makes the existing detector circuit components multi-functional. The diode serves both as the primary detection element and as part of the temperature compensation mechanism. The voltage sources and variable resistors serve dual purposes of biasing the diode and adjusting for temperature effects, reducing the need for completely separate compensation circuits.
Solution Approach 2:
The patent merges the temperature compensation function with the power detection function by integrating the bias voltage adjustment mechanism into the detection circuit itself. The control unit combines the output voltage signal processing with the bias voltage adjustment control, creating a unified system that performs both detection and compensation without requiring entirely separate circuit paths.
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 effectively suppresses voltage variations caused by temperature changes, allowing for accurate detection of AC signal power with minimal temperature-dependent fluctuations, improving the reliability of power detection in wireless communication systems.
Implementation Method 1
an input node of the first inverter coupled via a first capacitor to a transmission path for transmitting an AC signal
Implementation Method 2
the first inverter outputting an output voltage in accordance with power of the AC signal, wherein the output voltage increases with increasing temperature
Implementation Method 3
a first resistor coupled between the output node of the first inverter and an output node of the detector circuit
Data Source
AI summary
A detector circuit includes a first inverter including an input node coupled via a first capacitor to a transmission path for transmitting an AC signal, the first inverter outputting an output voltage in accordance with power of the AC signal, wherein the output voltage increases with increasing temperature, a second inverter including an input node coupled to the transmission path, the second inverter outputting an output voltage in accordance with power of the AC signal, wherein the output voltage decreases with increasing temperature, a third capacitor including one electrode coupled to either an output electrode of the first inverter or an output node of the second inverter, a first resistor coupled between the output node of the first inverter and an output node of the detector circuit, and a second resistor coupled between the output node of the second inverter and the output node of the detector circuit.