H-Bridge Motor Driver Circuit for Fan Run-Time During Power Loss
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Solution Overview
Problem
Existing computer systems face challenges in prolonging the operation of fans to dissipate heat during power loss, as backup power sources often run out of power before data backup is complete.
Innovation Solution
A driver circuit and driving circuit for a motor that includes a switching circuit with H-bridge configuration, utilizing pulse width modulation to control switches and transfer mechanical energy back to capacitors, extending power supply during power loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of moving object
If a backup battery is activated to provide power during main power source failure, then data backup can be maintained, but the operation time of the fan is limited by the backup battery capacity
Solution Approach 1:
The patent recovers kinetic energy from the motor during braking and coasting operations by converting it back to electrical energy through regenerative braking. This recovered energy is stored in capacitors or the main power source, reducing the power demand on the backup battery and extending the fan's operation time during power loss events.
Solution Approach 2:
The patent converts the harmful effect of motor back-EMF and residual kinetic energy during power loss into beneficial electrical energy. By utilizing the motor's back-EMF during coasting and braking phases, the system generates electricity that charges capacitors or feeds back to the power source, thereby extending operational duration without additional battery capacity.
2Temperature
If the fan operates at high speed to dissipate heat quickly, then heat dissipation efficiency is improved, but power consumption increases and reduces operation time during power loss
Solution Approach 1:
The patent dynamically adjusts fan speed based on real-time thermal conditions and power availability. During normal operation, the fan runs at optimal speeds for heat dissipation. During power loss events, the system transitions to regenerative braking mode where the motor acts as a generator, converting mechanical energy back to electrical energy to extend operation time while maintaining adequate cooling.
Solution Approach 2:
The patent employs periodic PWM (Pulse Width Modulation) control to regulate fan speed, alternating between high-speed cooling phases and lower-speed energy recovery phases. This periodic operation allows the system to achieve adequate heat dissipation over time while capturing energy during appropriate cycles, balancing thermal management with energy conservation.
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
Prolongs the operation of fans and main processing units by recycling energy to capacitors, ensuring data backup is completed even when the main power source is unplugged.
Implementation Method 1
utilizing pulse width modulation to control switches and transfer mechanical energy back to capacitors
Data Source
AI summary
A driver circuit for a switching circuit is provided. The driver circuit includes a PWM terminal, first to fourth gate control terminals configured to provide first to fourth control signals, a first output terminal, and a second output terminal. In a normal operation mode, during a first period of a first cycle, the first control signal and the fourth control signal are of a first voltage level, and during a second period of the first cycle, the second control signal and the fourth control signal are of the first voltage level. In a power loss mode, during the first period of the first cycle, the second control signal and the third control signal are of the first voltage level, and during the second period of the first cycle, the second control signal and the fourth control signal are of the first voltage level.