Laminated Doherty RF Module for Peak Amplifier Bias Timing
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Solution Overview
Problem
Existing Doherty amplifier circuits face issues with quality deterioration of radio frequency output signals due to timing shifts in peak amplifier activation and difficulty in controlling bias circuits in response to load fluctuations.
Innovation Solution
A radio frequency module with a Doherty amplifier circuit that includes a carrier amplifier and a peak amplifier, a branching circuit, a synthesis circuit, and a control circuit that varies the bias voltage threshold of the peak amplifier based on the radio frequency signal and drive level of the carrier amplifier, with the amplifiers integrated in a first circuit and the control circuit in a second integrated circuit, laminated for improved control and efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the bias circuit of the peak amplifier is controlled through detection of carrier amplifier saturation, then the peak amplifier can be activated, but the timing of activation may be shifted and the quality of the radio frequency output signal deteriorates
Solution Approach 1:
The control circuit monitors the drive level of the carrier amplifier in advance and activates the peak amplifier before the carrier amplifier reaches saturation. This preliminary action prevents timing shifts and maintains signal quality by ensuring the peak amplifier is ready to assist when needed, rather than reacting after saturation detection.
Solution Approach 2:
The control circuit uses feedback from the drive level detection of the carrier amplifier to dynamically control the bias voltage of the peak amplifier. This closed-loop control ensures accurate timing by continuously monitoring carrier amplifier performance and adjusting peak amplifier activation accordingly, preventing quality deterioration.
2Reliability
If the bias circuit of the peak amplifier is controlled based on radio frequency input signal level, then the peak amplifier can be activated, but it is difficult to control in response to load fluctuation and the quality of the radio frequency output signal deteriorates
Solution Approach 1:
The control circuit dynamically adjusts the bias voltage of the peak amplifier based on real-time drive level monitoring of the carrier amplifier. This dynamic control mechanism enables the system to adapt to load fluctuations by continuously optimizing the peak amplifier's activation timing and bias conditions, maintaining signal quality under varying operating conditions.
Data Source
AI summary
A radio frequency that includes a carrier amplifier and a peak amplifier, a 90° hybrid circuit connected to an input end of the carrier amplifier and an input end of the peak amplifier, a coupler connected to an output end of the carrier amplifier and an output end of the peak amplifier, and a control circuit configured to vary a threshold value of a bias voltage of the peak amplifier based on a radio frequency signal input to the 90° hybrid circuit or the carrier amplifier, and a signal indicating a drive level of the carrier amplifier, in which the carrier amplifier and the peak amplifier are included in an integrated circuit, the control circuit is included in an integrated circuit, and the integrated circuit and the integrated circuit are laminated.