High Frequency Power Amplifier Temperature Compensation
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Solution Overview
Problem
Conventional open-loop high frequency power amplifier circuits experience output power variations due to temperature dependency, even with constant bias voltage applied to the amplifying device's control terminal, leading to deviations in output power characteristics.
Innovation Solution
A temperature-dependent operating power supply voltage control circuit is introduced, which generates and applies a power supply voltage to the amplifying devices, compensating for temperature-induced deviations in saturation voltage, thereby maintaining consistent output power without requiring software-based temperature compensation in the baseband circuit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a conventional open-loop power amplifier circuit uses a constant bias voltage applied to the amplifying device's control terminal, then the circuit structure is simple and the packaging density is high, but the output power varies with temperature due to temperature dependency of the amplifying device
Solution Approach 1:
The patent changes the parameter of power supply voltage from constant to variable, making it dependent on temperature. The power supply voltage control circuit adjusts the power supply voltage based on temperature detection to compensate for temperature-induced variations in the amplifying device's characteristics, thereby maintaining consistent output power across different temperatures
Solution Approach 2:
The patent introduces a feedback mechanism where the temperature-dependent power supply voltage control circuit continuously monitors temperature and adjusts the power supply voltage accordingly. This closed-loop control compensates for temperature effects on the amplifying device, ensuring stable output power without increasing overall circuit complexity
2Reliability
If software-based temperature compensation is implemented in the baseband circuit, then output power consistency across temperature ranges is improved, but the burden on developers increases and system complexity increases
Solution Approach 1:
The patent replaces the software-based temperature compensation mechanism with a hardware-based power supply voltage control circuit. This circuit directly compensates for temperature effects through analog voltage adjustment, eliminating the need for complex software algorithms and reducing development burden while maintaining output power consistency
Solution Approach 2:
The patent introduces a power supply voltage control circuit as an intermediary between the temperature detection mechanism and the amplifying device. This intermediary component handles temperature compensation in the hardware domain, simplifying the overall system architecture and reducing the burden on baseband software development
Data Source
AI summary
A high frequency power amplifier circuit includes amplifying devices whose control terminals (gate or base terminals) are supplied with a bias voltage. The high frequency power amplifier circuit keeps constant the bias voltage so that the amplifying devices operate in a saturation region. The high frequency power amplifier circuit controls an operating power supply voltage supplied to the amplifying devices in accordance with an output request level to control output power. A device (diode) having temperature dependency is provided for an operating power supply voltage control circuit that controls the operating power supply voltage for the amplifying devices in accordance with the output request level. The operating power supply voltage control circuit is configured to generate the operating power supply voltage corresponding to the device's temperature characteristics and supply it to the amplifying devices.