Timepiece Dual-Frequency Motor Control Circuit
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Solution Overview
Problem
Analog electronic timepieces face increased power consumption due to high-speed processing requirements for tasks like communication and display, which overload the CPU and lead to inefficient power management.
Innovation Solution
Implementing a dual-frequency approach where a main control circuit operates at a high frequency for overall control and a motor control unit operates at a lower frequency to generate drive pulses for the motor, allowing for asynchronous clock signals and reducing power consumption by optimizing the timing and operation of the indicating hands.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the CPU operates at high speed to process communication and display tasks, then processing speed is improved, but power consumption increases
Solution Approach 1:
The control system is divided into two independent frequency domains: a main control circuit operating at high frequency (100 MHz) for communication and display tasks, and a motor control unit operating at low frequency (32 kHz) for motor control. This segmentation allows each component to operate independently at its optimal frequency, enabling high-speed processing without proportionally increasing power consumption for motor control operations.
2Measurement precision
If the CPU controls all functions including motor control at high frequency, then control precision is improved, but power consumption increases
Solution Approach 1:
The patent separates motor control functions from the main CPU by implementing a dedicated motor control unit that operates at a lower frequency. This segmentation maintains control precision for motor operations while reducing the power consumption burden on the main CPU, as the motor control unit handles timing-critical motor control tasks independently.
Solution Approach 2:
Different parts of the system are assigned different operational characteristics: the main control circuit operates at high frequency for tasks requiring rapid processing, while the motor control unit operates at low frequency for tasks requiring precise timing but not high-speed computation. This local differentiation optimizes overall system efficiency.
3Use of energy by moving object
If asynchronous clock signals are used for main control and motor control, then power consumption is reduced, but system complexity increases
Solution Approach 1:
The system uses two independent clock sources: a high-frequency clock for the main control circuit and a low-frequency clock for the motor control unit. This segmentation into independent frequency domains allows asynchronous operation, reducing power consumption while managing complexity through clear separation of concerns.
Data Source
AI summary
A timepiece, in which an indicating hand is driven by a motor and high speed processing is required for driving a load other than the indicating hand, includes a main control circuit that instructs drive timing of the motor so as to drive the load, and that is operated by an operation frequency serving as a first frequency, and a motor control unit that generates a drive pulse for driving the motor, and that is operated by an operation frequency serving as a second frequency which is lower than the first frequency.