Pulse Length Modulation Signaling for Lower-Rate Power Amplifier Control

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Solution Overview

Problem

Current pulse length modulation techniques require high-speed digital data lines for transmitting switching information between controlling and switching circuits, leading to increased resource demands and potential noise issues, especially at high switching rates like 10 GHz.

Innovation Solution

Generating coded information elements for pulse length and position in the controlling circuit, which are then decoded in the switching circuit to produce corresponding PLM sequences, reducing the data speed and amount of information transmitted, and using ternary modulated signals to minimize transistor 'on'-time and eliminate offset-related power loss.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If high-speed digital data lines are used to transmit switching information at 10 GHz switching rate, then the switching information can be transmitted accurately, but the resource requirements and noise suppression demands increase significantly

Engineering Contradiction:

Improveswitching information transmission accuracyVSAvoidtransmitter and receiver logic complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent extracts only the essential control parameters (pulse width and position information) from the complete switching information, transmitting only these critical elements instead of the full PLM sequences. This reduces the data transmission rate from 2x10Gbit/s to much lower rates while maintaining accurate control of the power amplifier switching behavior.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The controlling circuit generates coded information elements in advance that contain pre-calculated pulse width and position data. This preliminary encoding allows the switching circuit to reconstruct the full PLM sequences locally without requiring high-speed transmission of complete switching waveforms, thereby reducing real-time transmission requirements.

Inventive Principle:

Principle #10Preliminary action

2Productivity

If two high-speed digital data lines are used to transmit ternary switching signal at 2x10Gbit/s, then the switching information can be transmitted, but the requirements to transmitter, receiver logic and board layout increase

Engineering Contradiction:

Improvedata transfer rateVSAvoidtransmitter and receiver logic

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent changes the transmission parameters from high-rate binary switching signals to lower-rate coded information elements representing pulse width and position. This parameter transformation allows the same control functionality to be achieved with reduced data rates and simpler transmission infrastructure.

Inventive Principle:

Principle #35Parameter changes

3Device complexity

If parallel signal lines at lower data rates are used, then the data transmission requirements are reduced, but the space requirements increase due to more pins and wires

Engineering Contradiction:

Improvedata transmission requirementsVSAvoidboard space

Core Design Contradiction:

Device complexityVSArea of stationary object

Solution Approach 1:

The patent transitions from spatial parallelism (multiple parallel signal lines) to temporal serialization (single or fewer lines transmitting coded information over time). By encoding pulse width and position information in a compact format that can be transmitted sequentially at lower rates, the patent reduces the number of physical connections needed while maintaining control precision.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

4Quantity of substance

If coded information elements are transmitted instead of PLM sequences, then the amount of data to be transmitted is reduced, but the decoding complexity in the switching circuit increases

Engineering Contradiction:

Improveamount of information transmittedVSAvoidswitching circuit decoding logic

Core Design Contradiction:

Quantity of substanceVSDevice complexity

Solution Approach 1:

The switching circuit is designed to autonomously decode the transmitted coded information elements and generate the complete PLM sequences internally. The circuit uses local resources (shift registers, timing generators) to reconstruct the switching waveforms from the compact coded input, eliminating the need for complex external transmission infrastructure while maintaining full control functionality.

Inventive Principle:

Principle #25Self-service

Data Source

PatentEP2888850B1Transmission of pulse length modulation information

Publication Date: 2020.01.22 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)

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AI summary

The invention refers to switching a physical quantity, wherein the switching is performed by a switching element (SW) according to a control signal received from a control circuit (1 1 ), comprising detecting from the control signal (CS) a first number indicative of a time length, and a second number indicative of a point in time, generating a switching signal (S) comprising a switching pulse having a pulse length according to the time length and a pulse position according to the point in time, and providing the switching signal to the switching element (SW). The invention further refers to a power amplifier and to a corresponding computer program.