Power Amplifier Bias Control for Idle Timeslot Shutdown

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Solution Overview

Problem

Current power amplifiers in base station systems suffer from low efficiency due to static power dissipation during idle timeslots, with existing solutions being limited in applicability and reliability, and requiring complex high-cost control circuits.

Innovation Solution

A system that uses a controller to apply bias voltage control signals to power amplifier transistors based on network equipment states, switching off the amplifier during idle timeslots and switching on during busy timeslots, thereby reducing static power dissipation and improving efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If the power amplifier operates in Class A or Class AB with static working current > 0A, then linearity is improved, but efficiency deteriorates during idle timeslots due to static power dissipation

Engineering Contradiction:
ImprovelinearityVSAvoidstatic power dissipation
Core Design Contradiction:
Stability of the object's compositionVSLoss of energy

Solution Approach 1:

The power amplifier is switched between idle and busy states periodically according to timeslot requirements. During idle timeslots, the amplifier is turned off to eliminate static power dissipation, and during busy timeslots, it is activated to provide RF power, achieving periodic operation that reduces overall energy loss while maintaining linearity when needed.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The working state of the power amplifier is made dynamic rather than static. The amplifier transitions between Class AB operation (during busy timeslots) and complete shutdown (during idle timeslots), allowing the system to adapt its power consumption level according to actual service requirements, thereby resolving the contradiction between maintaining linearity and reducing energy loss.

Inventive Principle:
Principle #15Dynamics

2Loss of energy

If the drain electrode voltage is adjusted to 0V to improve efficiency during idle state, then power dissipation is reduced, but response time increases due to high-capacitance capacitor charging/discharging

Engineering Contradiction:
Improvepower dissipationVSAvoidresponse time
Core Design Contradiction:
Loss of energyVSLoss of time

Solution Approach 1:

The high-capacitance capacitor that causes slow response is removed from the circuit. Instead of using a capacitor-based voltage adjustment method, the invention directly controls the power supply to the power amplifier transistor, eliminating the capacitive delay and achieving fast response time while maintaining low power dissipation during idle states.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The electrical capacitor-based voltage control mechanism is replaced with a direct power supply control mechanism. By controlling the power supply switch rather than adjusting capacitor voltages, the system achieves faster response time without the inertial effects of high-capacitance components, while still achieving the goal of reducing power dissipation during idle periods.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Power

If high-voltage (28V) and large current (10A) power supply is used to drive the power amplifier, then output power capability is improved, but control circuit complexity and cost increase

Engineering Contradiction:
Improveoutput power capabilityVSAvoidcontrol circuit complexity
Core Design Contradiction:
PowerVSDevice complexity

Solution Approach 1:

The control function is segmented into two independent parts: (1) a simple control circuit that generates low-voltage control signals, and (2) a power supply unit that handles high-voltage and large current. The control circuit only needs to manage low-power switching signals, while the power supply unit handles the high-power delivery, thereby simplifying the control circuit design while maintaining high output power capability.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

A control signal acts as an intermediary between the simple control circuit and the high-power power supply unit. The control circuit generates low-voltage control signals that trigger the power supply unit to provide or cut off high-voltage and large current to the power amplifier, allowing complex power delivery without requiring a complex control circuit.

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentEP3579440B1Method and device for controlling power amplification
Publication Date: 2024.11.27 HUAWEI TECH CO LTD
  • EP3579440B1 patent drawingFigure 1~4
  • EP3579440B1 patent drawingFigure 5~6
  • EP3579440B1 patent drawingFigure 7~8

AI summary

A method and a device for controlling power amplification are provided. The method for controlling power amplification includes: when the NE is in an Idle state, outputting a voltage signal corresponding to the Idle state for enabling the power amplifier to switch off; and applying the voltage signal corresponding to the Idle state to a grid electrode or a base electrode of at least one power amplifier transistor in a power amplifier for enabling the power amplifier to switch off. Thereby, static power dissipation of the power amplifier when no RF power is output is eliminated, and the efficiency of the power amplifier is improved.