Motor Control Circuit for Electronic Timepiece Speed Consistency
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Solution Overview
Problem
Existing motor control technologies for electronic timepieces cannot maintain a constant drive speed, leading to variations in rotor rotation time due to load and temperature conditions, making them unsuitable for displays requiring consistent motor speed.
Innovation Solution
The electronic timepiece incorporates a motor control circuit with a driver, current detector, controller, detection signal output device, reference signal output device, and drive cycle adjuster, which adjusts the drive cycle based on detected current values and timing conditions to maintain consistent motor speed by comparing output timings of detection and reference signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional motor control is used with fixed drive timing, then the control structure is simple, but the rotor rotation time varies due to load and temperature changes, causing inconsistent display speed
Solution Approach 1:
The patent implements feedback control by detecting the actual rotor position during rotation and comparing it with the target position. The drive timing is then adjusted based on the detected position feedback to compensate for variations caused by load and temperature changes, ensuring consistent display speed while maintaining a relatively simple control structure.
Solution Approach 2:
The patent makes the motor control dynamic by adjusting the drive timing based on real-time rotor position detection. Instead of using fixed drive timing, the system dynamically modifies the drive cycle to compensate for variations in rotor rotation time, thereby achieving consistent display speed under varying conditions.
2Speed
If the motor drive timing is adjusted to compensate for speed variations, then the display speed consistency is improved, but the control complexity increases
Solution Approach 1:
The system uses feedback from rotor position detection to adjust the drive timing. By continuously monitoring the rotor position and comparing it with the target position, the system automatically compensates for speed variations without requiring complex manual adjustment mechanisms, thus improving speed consistency while keeping the control mechanism relatively simple.
Solution Approach 2:
The motor control system performs self-adjustment by using its own rotor position detection capability to automatically modify its drive timing. This self-service approach eliminates the need for external complex control mechanisms, as the system uses its inherent detection functions to regulate its own speed consistency.
3Productivity
If the drive cycle is shortened to increase motor speed, then the display responsiveness is improved, but the power consumption increases
Solution Approach 1:
The system dynamically adjusts the drive cycle based on actual rotor position detection rather than using a fixed short drive cycle. This allows the motor to achieve necessary display update speeds only when needed, rather than continuously operating at high speed, thereby improving display responsiveness while reducing overall power consumption.
Solution Approach 2:
The system changes the drive cycle parameters dynamically based on detected rotor position and speed requirements. Instead of maintaining a constantly shortened drive cycle that would increase power consumption, the system adjusts drive timing parameters to match actual display needs, achieving high productivity only when necessary and reducing energy usage during normal operation.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution enables the motor to operate at a constant speed, ensuring accurate and synchronized display functions in electronic timepieces, particularly for chronograph measurements, by adjusting drive cycles and current settings based on detected conditions.
Implementation Method 1
a motor (45) with a coil (130)
Data Source
AI summary
Provided is an electronic timepiece capable of suppressing variation in the drive speed of a rotor, and driving a motor at a constant speed. The electronic timepiece has a driver; a controller that controls the driver to the on state or the off state according to a current flowing through a coil of a motor; a detection signal output device configured to output a detection signal when the on time or the off time, which are the continuous time of the on state and off state of the driver, meets a specific condition; a reference signal output device that outputs a reference signal used as a reference of a drive speed of the motor; and a drive cycle adjuster that compares the output timing of the detection signal and the reference signal, shortens the drive cycle when the detection signal is output after the reference signal, and when the detection signal is output before the reference signal, lengthens the drive cycle of the motor.