Power Amplifier Ramp-Up Control for Overcurrent and Saturation

Solution Overview

Problem

Mobile terminals face performance issues due to varying Voltage Standing Wave Ratio (VSWR) at the output of power amplifiers, leading to excessive current drain and reduced battery life, as well as spectral noise and distortion in the output waveform, caused by varying load impedance and environmental factors.

Innovation Solution

A system and method for detecting and correcting over-current and over-voltage conditions in power amplifier circuitry, using current and voltage detection signals and inverse ramping profiles to adjust the power control signal, thereby reducing output power and correcting these conditions during ramp-up for a transmit burst.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If the supply voltage is increased to provide target output power when load impedance increases, then output power is maintained, but spectral noise is generated and waveform distortion occurs due to battery voltage clipping

Engineering Contradiction:

Improveoutput powerVSAvoidspectral noise and waveform distortion

Core Design Contradiction:

PowerVSObject-generated harmful factors

Solution Approach 1:

The patent applies preliminary action by detecting over-voltage conditions during the ramp-up phase before they cause spectral noise and waveform distortion. The system proactively reduces the power control signal when the supply voltage approaches the battery's maximum voltage, preventing the hard limit clipping that would otherwise truncate the output waveform and generate spectral noise during transmit bursts.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent implements feedback by continuously monitoring the supply voltage to the power amplifier and comparing it against the battery's maximum voltage capability. When the supply voltage approaches the battery limit, the system feeds back a correction signal to reduce the power control signal, thereby maintaining output power within achievable limits and preventing waveform distortion and spectral noise generation.

Inventive Principle:

Principle #23Feedback

2Adaptability or versatility

If the supply voltage is varied to provide amplitude modulation, then modulation is achieved, but severe distortion of the desired modulation pattern occurs due to battery voltage hard limit

Engineering Contradiction:

Improveamplitude modulation capabilityVSAvoidmodulation pattern integrity

Core Design Contradiction:

Adaptability or versatilityVSStability of the object's composition

Solution Approach 1:

The patent applies preliminary action by detecting over-voltage conditions during the ramp-up phase before they cause spectral noise and waveform distortion. The system proactively reduces the power control signal when the supply voltage approaches the battery's maximum voltage, preventing the hard limit clipping that would otherwise truncate the output waveform and generate spectral noise during transmit bursts.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent implements feedback by continuously monitoring the supply voltage to the power amplifier and comparing it against the battery's maximum voltage capability. When the supply voltage approaches the battery limit, the system feeds back a correction signal to reduce the power control signal, thereby maintaining output power within achievable limits and preventing waveform distortion and spectral noise generation.

Inventive Principle:

Principle #23Feedback

3Power

If the load impedance decreases below ideal impedance, then output current increases, but excessive current drain reduces battery life

Engineering Contradiction:

Improveoutput powerVSAvoidbattery life

Core Design Contradiction:

PowerVSUse of energy by moving object

Solution Approach 1:

The patent implements feedback by monitoring the current drawn by the power amplifier and comparing it against a predetermined maximum current threshold. When the current exceeds this threshold due to decreased load impedance, the system feeds back a correction signal to reduce the power control signal, thereby limiting current drain and preserving battery life while maintaining acceptable output power levels.

Inventive Principle:

Principle #23Feedback

Data Source

PatentUS7962109B1Excess current and saturation detection and correction in a power amplifier

Publication Date: 2011.06.14 QORVO US INC

AI summary

A system and method for detecting and correcting over-current and/or over-voltage conditions in power amplifier circuitry in a transmit chain of a mobile terminal are provided. In general, over-current detection and correction circuitry combines a current detection signal indicative of a current provided to or drained by the power amplifier circuitry during ramp-up for a transmit burst and a substantially inverse current ramping profile to provide a first constant value. The first constant value is compared to a current threshold or limit value to determine whether an over-current condition exists. If an over-current condition exists, the over-current detection and correction circuitry operates to reduce the output power of the power amplifier circuitry during ramp-up for the transmit burst to correct for the over-current condition. In a similar manner, over-voltage detection circuitry operates to detect and correct over-voltage conditions during ramp-up for the transmit burst.