Motor Driver PWM Control Using Common Voltage Feedback
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Solution Overview
Problem
Conventional motor drivers cause excessive power consumption and potential damage to motors due to high-duty cycle signals maintaining high-speed operation, leading to large currents and overheating.
Innovation Solution
A motor driver that adjusts power based on common voltage by calculating a common voltage difference and determining a duty cycle adjustment value, reducing the duty cycle when the common voltage exceeds a threshold to prevent excessive power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the motor driver outputs a high duty cycle signal to drive the fan motor at high speed, then the cooling efficiency is improved, but the power consumption becomes excessive and may damage the motor
Solution Approach 1:
The patent implements dynamic duty cycle adjustment based on real-time voltage detection. The control circuit continuously monitors the voltage at the motor terminal and dynamically modifies the PWM duty cycle accordingly. When voltage exceeds a threshold, the duty cycle is reduced to prevent excessive power consumption, while allowing high speed operation when voltage is within safe limits. This dynamic adaptation resolves the contradiction between maintaining high speed and preventing excessive power consumption.
Solution Approach 2:
The patent employs a feedback mechanism where the control circuit detects the actual voltage at the motor terminal and uses this information to adjust the PWM signal duty cycle. The detection circuit provides real-time feedback about the voltage condition, which the control circuit processes to determine the appropriate duty cycle adjustment. This closed-loop feedback system enables the motor driver to automatically balance between speed performance and power consumption safety.
2Duration of action of moving object
If the high-side switch is maintained in a turned on state for a long period to enable high current flow, then the fan motor can run at high speed, but the motor may be damaged due to excessive power consumption
Solution Approach 1:
The patent makes the switch on-time duration dynamic rather than fixed. The control circuit continuously adjusts the PWM duty cycle based on real-time voltage detection. When the detected voltage indicates safe operating conditions, the high-side switch remains on for longer periods to maintain high speed. When voltage exceeds thresholds, the duty cycle is reduced, automatically shortening the switch on-time duration to prevent motor damage. This dynamic timing adjustment resolves the contradiction between duration and reliability.
3Productivity
If a constant high duty cycle is used to ensure quick cooling, then the cooling performance is improved, but the motor is at risk of damage from excessive power consumption
Solution Approach 1:
The patent transforms the constant duty cycle into a dynamic parameter that adapts to real-time voltage conditions. The control circuit monitors voltage continuously and adjusts the PWM duty cycle accordingly. When voltage is within safe limits, the duty cycle maintains high values for optimal cooling performance. When voltage exceeds thresholds, the duty cycle is automatically reduced to prevent motor damage. This dynamic adjustment resolves the contradiction between cooling productivity and motor safety.
Solution Approach 2:
The patent applies preliminary anti-action by detecting voltage conditions before excessive power consumption can occur. The control circuit continuously monitors voltage and proactively adjusts the duty cycle downward when voltage approaches dangerous levels, preventing motor damage before it happens. This preventive approach allows the system to maintain high cooling performance during safe conditions while automatically protecting the motor when voltage conditions become hazardous.
Data Source
AI summary
A motor driver for adjusting power based on a common voltage is provided. The motor driver includes a common voltage difference calculation circuit, a duty cycle determination circuit, a signal generator circuit, a control circuit, a driver circuit and an output stage circuit. The common voltage difference calculation circuit calculates a difference between the common voltage received by the output stage circuit and a threshold. The duty cycle determination circuit determines a duty cycle adjustment value according to the difference. The signal generator circuit adjusts a plurality of waveform signals according to the duty cycle adjustment value. The control circuit outputs control signals according to the plurality of waveform signals. The driver circuit outputs driving signals according to the control signals. The output stage circuit operates to drive the motor according to the common voltage and the driving signals.