Microcomputer Mode Transition Control Circuit

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Solution Overview

Problem

Microcomputers face challenges in suppressing current consumption during mode transitions, particularly when transitioning between standby modes, as existing methods require operating the CPU and often necessitate temporary transitions through higher power modes, leading to increased energy usage.

Innovation Solution

A control circuit that determines the appropriate mode for the CPU to transition to based on the type of interruption request when in a standby mode, allowing direct transitions between standby modes without going through the RUN mode, thereby minimizing current consumption.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the CPU operates to execute commands for mode transition (memory access or SFR writing), then the operational mode can be changed, but current consumption increases

Engineering Contradiction:

Improvemode transition capabilityVSAvoidcurrent consumption

Core Design Contradiction:

Adaptability or versatilityVSUse of energy by moving object

Solution Approach 1:

The patent extracts the mode transition control function from the CPU and assigns it to a dedicated mode transition control circuit. This circuit directly controls the clock supply to the CPU without requiring CPU execution of transition commands, thereby eliminating the current consumption associated with CPU operation during mode transitions while preserving full mode transition capability

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent introduces a mode transition control circuit as an intermediary between the system control logic and the CPU clock supply. This intermediary circuit can directly modify clock supply settings based on control signals without requiring CPU intervention, enabling mode transitions with minimal current consumption while maintaining adaptability across different operational modes

Inventive Principle:

Principle #24Intermediary (Mediator)

2Adaptability or versatility

If the microcomputer transitions through the RUN mode to change between standby modes, then mode flexibility is maintained, but current consumption increases due to temporary high-power mode

Engineering Contradiction:

Improvestandby mode transition flexibilityVSAvoidcurrent consumption during transition

Core Design Contradiction:

Adaptability or versatilityVSUse of energy by moving object

Solution Approach 1:

The patent extracts the clock supply control function from CPU operation and assigns it to a dedicated control circuit that can directly switch between standby modes (STOP and HALT) without requiring CPU execution. This enables direct transitions between low-power modes while maintaining the flexibility to select appropriate standby modes based on system requirements

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent enables direct transitions between standby modes by allowing the mode transition control circuit to modify clock supply settings without requiring the system to pass through the RUN mode. This skipping of the high-power intermediate state significantly reduces current consumption during mode transitions while preserving full adaptability

Inventive Principle:

Principle #21Skipping (Rushing through)

3Use of energy by moving object

If the CPU is stopped in standby mode to reduce current consumption, then power savings are achieved, but the ability to execute mode transition commands is lost

Engineering Contradiction:

Improvecurrent consumptionVSAvoidmode transition capability

Core Design Contradiction:

Use of energy by moving objectVSAdaptability or versatility

Solution Approach 1:

The patent introduces a mode transition control circuit as an intermediary that retains the ability to control clock supply even when the CPU is stopped in standby mode. This circuit can receive external or internal trigger signals and execute mode transitions without requiring CPU participation, thereby maintaining adaptability while achieving significant power savings

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent segments the control functions by separating mode transition control from CPU operation. The mode transition control circuit operates independently from the CPU, allowing it to execute mode transitions using minimal current while the CPU remains in its low-power standby state, thus resolving the contradiction between power savings and transition capability

Inventive Principle:

Principle #1Segmentation

Data Source

PatentUS8677164B2Microcomputer and control method thereof

Publication Date: 2014.03.18 RENESAS ELECTRONICS CORP

AI summary

A microcomputer according to the present invention includes: a CPU (Central Processing Unit) that has a plurality of modes including a usual operational mode and a STANDBY mode, a clock supply being stopped in the STANDBY mode; a clock generation circuit that generates a clock supplied to the CPU; and a control circuit that monitors a mode of the CPU, determines a mode to which the CPU should transit according to the mode of the CPU and a type of an interruption request to the CPU, and controls the clock generation circuit according to the determined mode.