Dual-Loop Power Control Circuit for Stable High-Speed Operation
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Solution Overview
Problem
Existing power control circuits for wireless communication devices face instability and accuracy issues due to temperature changes and power supply variations in analog circuits, and digital circuits can lead to oscillations during high-speed power control in burst modes like GSM, making it challenging to achieve stable operation across multiple frequency bands and systems.
Innovation Solution
A power control circuit with a digital feedback loop and an analog feedback loop that converts detected power signals to digital and analog signals respectively, allowing for high-speed operation by eliminating digital signal processing delays and stabilizing power control, enabling the circuit to operate stably across multiple frequency bands and systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If an analog feedback circuit is used for power control, then the circuit can operate at high speed, but the stability and accuracy deteriorate due to temperature changes and power supply variations
Solution Approach 1:
The feedback circuit is segmented into two independent paths: an analog feedback path for high-speed response and a digital feedback path for stable, accurate control. Each path processes power control signals independently, allowing the system to leverage the advantages of both analog and digital domains without the drawbacks of either alone.
Solution Approach 2:
The system changes the operational parameters of the feedback circuit by using different conversion rates for the analog-to-digital converters in each path. The first ADC uses a first conversion rate while the second ADC uses a second conversion rate, allowing optimization of each path for its specific function while maintaining overall system stability and speed.
2Reliability
If a digital feedback circuit is used for power control, then the stability and accuracy improve, but the operation speed deteriorates due to digital signal processing delays
Solution Approach 1:
The feedback circuit is segmented into two independent paths: an analog feedback path for high-speed response and a digital feedback path for stable, accurate control. Each path processes power control signals independently, allowing the system to leverage the advantages of both analog and digital domains without the drawbacks of either alone.
Solution Approach 2:
The analog feedback path acts as an intermediary that provides high-speed response to rapid changes in power requirements, while the digital feedback path provides stable, accurate long-term control. The two paths work together, with the analog path compensating for the speed limitations of digital processing.
3Adaptability or versatility
If a single power control circuit is designed to support multiple frequency bands and systems, then the adaptability improves, but the circuit complexity increases
Solution Approach 1:
The power control circuit is designed with universal components that can operate across multiple frequency bands and communication systems. The dual feedback path architecture with configurable ADC conversion rates provides a unified solution that adapts to different operational requirements without requiring separate dedicated circuits for each band or mode.
Data Source
AI summary
There is provided a power control circuit having a stable high-speed operation, and a semiconductor device and a transceiver circuit using it. The power control circuit controls the gain of an amplifier so that power outputted from the amplifier reaches a desired value according to a digital control signal. The power control circuit includes a digital feedback loop which converts a detected signal obtained by detecting a value of the output power of the amplifier to a digital signal, determines a differential between the digital signal and the digital control signal, converts the differential to an analog signal and outputs a first feedback signal, an analog feedback loop which outputs a high frequency element corresponding to a differential between an analog signal to which the digital control signal is converted and the detected signal, as a second feedback signal, and an adder which determines the sum of the first and the second feedback signal and outputs a gain control signal for controlling the gain of the amplifier.