Dual Envelope Tracking Doherty Circuit for Linear Power Amplification
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Solution Overview
Problem
Conventional Doherty dual amplifier circuits experience significant non-linearity and efficiency losses due to the activation of the peaking amplifier at average power levels, which negatively impacts performance, especially in 5G-NR communication systems where higher data rates are required.
Innovation Solution
The implementation of a barely Doherty dual envelope tracking (BD2E) circuit with an improved impedance inverter that isolates the peaking amplifier from the carrier amplifier, allowing for independent control and modulation using separate supply voltage signals, thereby enhancing linearity and preserving efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the peaking amplifier is activated at average power levels in a conventional Doherty dual amplifier circuit, then power amplification capability is improved, but linearity deteriorates and efficiency losses increase
Solution Approach 1:
The patent divides the control of the Doherty amplifier into two independent segments: the carrier amplifier and the peaking amplifier. By providing separate supply voltage control signals (VCC_CARRIER and VCC_PEAKING) from the envelope tracking circuit, each amplifier can be controlled independently to maintain linearity while achieving power amplification. This segmentation allows the peaking amplifier to be activated at appropriate power levels without degrading the linearity of the overall system.
2Power
If the peaking amplifier is activated at average power levels, then power output is improved, but efficiency deteriorates
Solution Approach 1:
The patent implements dynamic control of both the carrier and peaking amplifiers through the envelope tracking circuit. The supply voltages VCC_CARRIER and VCC_PEAKING are dynamically adjusted based on the instantaneous power requirements. This dynamic control ensures that the peaking amplifier is activated only when needed (at appropriate power levels rather than continuously at average power), thereby maintaining high efficiency while providing the required power output capability.
3Reliability
If independent control of carrier and peaking amplifiers is implemented, then linearity is improved, but device complexity increases
Solution Approach 1:
The envelope tracking circuit serves multiple functions: it generates both the VCC_CARRIER and VCC_PEAKING supply voltage signals, provides dynamic control for both amplifiers, and ensures proper activation timing. By using a single multi-functional envelope tracking circuit rather than separate control circuits for each amplifier, the patent achieves independent control and improved linearity while minimizing the increase in overall device complexity.
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
This approach maintains linearity and reduces efficiency losses by allowing independent control of the carrier and peaking amplifiers, improving power amplification efficiency and reducing non-linearity issues across the operational range.
Implementation Method 1
The impedance inverter comprises a supply voltage input node, wherein a supply voltage received at the supply voltage input node modulates the carrier amplifier
Implementation Method 2
The transformer circuit comprises a second supply voltage input node, wherein a second supply voltage received at the second supply voltage input node modulates the peaking amplifier separately from modulation of the carrier amplifier
Implementation Method 3
The BD2E circuit includes an improved impedance inverter that isolates the peaking amplifier from the carrier amplifier to allow this independent control
Data Source
AI summary
A barely Doherty dual envelope tracking (BD2E) circuit has a transmitter chain that includes an envelope tracking (ET) circuit that controls a Doherty dual power amplifier array. The ET circuit provides two control signals (supply voltage signals) that are used to control or modulate a carrier amplifier and a peaking amplifier independently of one another. The BD2E circuit includes an improved impedance inverter that isolates the peaking amplifier from the carrier amplifier to allow this independent control. By providing independent control, greater linearity may be provided while preserving the efficiency of the circuit.