Temperature Detection Circuit With Bypass Bias Control for PA Compensation
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Solution Overview
Problem
Existing temperature compensation circuits for power amplifiers in wireless communication devices fail to accurately compensate for amplification factor changes due to non-linear relationships between voltage signal changes and temperature changes, leading to increased error vector magnitude (EVM) at high surrounding temperatures.
Innovation Solution
A temperature detection circuit with a series connection circuit including a temperature detection element and a first resistance element, and a current bypass circuit with a first transistor, which generates a bias voltage for the power amplifier, allowing for accurate temperature compensation across a wide temperature range by adjusting the amplification factor based on the temperature detection signal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a simple temperature compensation circuit is used, then the device complexity is low, but the measurement precision of temperature compensation deteriorates at high temperatures
Solution Approach 1:
The temperature detection function is segmented into two parallel paths: a main detection path (temperature detection element + first resistance element) and a bypass path (first transistor). This segmentation allows the circuit to handle different temperature ranges through different paths, improving overall detection precision without requiring a completely complex new circuit design.
Solution Approach 2:
The bypass current through the first transistor is dynamically adjusted based on temperature conditions. At high temperatures, the bypass current increases to compensate for the non-linear response of the temperature detection element, thereby maintaining measurement precision across a wide temperature range while using a relatively simple circuit structure.
2Ease of operation
If the amplification factor is kept constant, then the device operation is simple, but the reliability of signal transmission deteriorates due to EVM increase at high temperatures
Solution Approach 1:
The circuit uses temperature detection feedback to dynamically adjust the bias voltage of the power amplifier. The temperature detection signal is fed back to the control circuit, which then adjusts the amplification factor accordingly. This feedback mechanism maintains signal transmission reliability across temperature variations while keeping the operation relatively simple through automatic adjustment.
Solution Approach 2:
The bias voltage parameter of the power amplifier is changed based on temperature conditions. By adjusting this parameter, the amplification factor is optimized for different temperature ranges, maintaining EVM within acceptable limits and ensuring reliable signal transmission without complex operational intervention.
3Device complexity
If no temperature compensation is applied, then the device complexity is low, but the manufacturing precision of amplification factor control deteriorates
Solution Approach 1:
The temperature detection element continuously monitors temperature conditions in advance, and the control circuit proactively adjusts the bias voltage before significant amplification factor deviations occur. This preliminary action ensures precise amplification factor control across temperature ranges while maintaining relatively simple circuit implementation.
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 compensates for amplification factor changes across a wide temperature range, reducing EVM and maintaining signal quality even at high surrounding temperatures by increasing the rate of amplification factor increase with temperature rise.
Implementation Method 1
a temperature detection element and a first resistance element... A temperature detection signal is outputted from a connection part between the temperature detection element and the first resistance element
Implementation Method 2
control the amplification factor of the power amplifier by changing the bias voltage of a transistor of the power amplifier using this voltage signal
Data Source
AI summary
Provided is a temperature detection circuit that includes: a series connection circuit that is connected between a power supply voltage input terminal and ground and includes a temperature detection transistor and a first resistance element; and a current bypass circuit that includes a first transistor that is connected in parallel with the temperature detection element and allows a bypass current to flow therethrough. The temperature detection circuit outputs a temperature detection signal from a connection point between the temperature detection transistor and the first resistance element.