PWM Output Module with Automatic RAM Loading for Complex Waveforms

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Solution Overview

Problem

Existing PWM generation methods in micro-controller units (MCUs) require CPU intervention for dynamic setting changes, leading to high power consumption and limitations in pattern generation due to slow memory-mapped interfaces, making it difficult to meet real-time requirements.

Innovation Solution

A digital microprocessor device that allows automatic alteration of PWM signal characteristics without CPU intervention, using a counter and comparators to generate complex waveforms by loading parameters from RAM, enabling flexible and power-efficient output signal generation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If CPU is used to dynamically change PWM settings, then flexibility in waveform generation is improved, but power consumption increases and real-time performance deteriorates

Engineering Contradiction:
Improveflexibility in waveform generationVSAvoidpower consumption
Core Design Contradiction:
Adaptability or versatilityVSUse of energy by moving object

Solution Approach 1:

The patent extracts the PWM generation function from CPU control and implements it in dedicated hardware (PWM module with counter and comparator). This allows the PWM function to operate independently without CPU intervention, reducing power consumption while maintaining waveform generation flexibility through programmable parameters stored in memory.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The PWM module is designed to be self-sufficient with its own counter, comparator, and memory interface. The counter automatically increments and the comparator automatically compares counter values with duty cycle parameters, enabling the module to generate PWM waves autonomously without requiring continuous CPU service or intervention.

Inventive Principle:
Principle #25Self-service

2Adaptability or versatility

If CPU sequentially loads registers to change PWM settings, then waveform parameters can be modified, but response time increases due to slow memory-mapped interface

Engineering Contradiction:
Improveability to change waveform parametersVSAvoidresponse time
Core Design Contradiction:
Adaptability or versatilityVSSpeed

Solution Approach 1:

The patent implements preliminary action by pre-loading PWM parameters (such as period and duty cycle values) into dedicated registers or memory locations before PWM operation begins. The PWM module can then directly use these pre-configured values without requiring sequential register loading during operation, enabling rapid parameter changes and meeting real-time requirements.

Inventive Principle:
Principle #10Preliminary action

3Adaptability or versatility

If multiple PWM parameters are changed dynamically, then complex waveform patterns can be generated, but the number of required CPU operations increases

Engineering Contradiction:
Improvecomplexity of generatable patternsVSAvoidnumber of CPU operations
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent implements a universal PWM module that can generate multiple waveform patterns (PWM, wave train, one-shot) using a single integrated hardware structure. The module uses a common counter and comparator mechanism that can be configured through programmable parameters to produce different waveform types, eliminating the need for separate hardware circuits for each waveform pattern and reducing overall system complexity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Data Source

PatentEP3311239B1Waveform generation
Publication Date: 2025.11.26 NORDIC SEMICONDUCTOR
  • EP3311239B1 patent drawingFigure 1~2
  • EP3311239B1 patent drawingFigure 3~4
  • EP3311239B1 patent drawingFigure 5~6

AI summary

A digital microprocessor device (2) has: a central processing unit; a memory (8); and an output signal module (4). The output signal module comprises: a counter (6) arranged to count to a predetermined count value; and at least one comparator (10a, 10b, 10c) arranged to change an output signal (14a, 14b, 14c) from a first output state to a second output state when the counter reaches a predetermined comparator value. The output signal module is arranged to load automatically from the memory at least one parameter selected from the group comprising: the predetermined count value, the predetermined comparator value and the first output state or the second output state, without receipt of an instruction from the central processing unit.