2-Phase half-wave motor pre driver for fan motor # BA6901F Technical Documentation
## 1. Application Scenarios
### Typical Use Cases
The BA6901F is a 3-phase brushless DC motor driver IC primarily designed for precision motor control applications. Typical implementations include:
- Fan Motor Control Systems : Provides efficient 3-phase driving for CPU cooling fans, cabinet ventilation fans, and industrial exhaust systems
- Small Appliance Motors : Used in household appliances requiring reliable brushless motor control (blenders, food processors, vacuum cleaners)
- Office Automation Equipment : Implements motor control in printers, scanners, and copiers for paper handling mechanisms
- Automotive Auxiliary Systems : Controls blower motors in HVAC systems and cooling fans in automotive electronic control units
### Industry Applications
Consumer Electronics
- Computer peripherals (external hard drives, optical drives)
- Home entertainment systems (projector cooling, turntable motors)
- Smart home devices (automatic window openers, ventilation systems)
Industrial Automation
- Small conveyor belt systems
- Precision positioning mechanisms
- Laboratory equipment requiring stable rotational control
Automotive Electronics
- Electronic power steering auxiliary motors
- Battery cooling systems in electric vehicles
- Climate control blower motors
### Practical Advantages and Limitations
Advantages:
- Integrated Design : Combines pre-driver, output stages, and protection circuits in single package
- Low Power Consumption : Features standby mode with typical current of 10μA
- Thermal Protection : Built-in thermal shutdown prevents damage from overheating
- Wide Voltage Range : Operates from 4.5V to 18V, accommodating various power supply configurations
- Soft Switching : Reduces electromagnetic interference through optimized switching characteristics
Limitations:
- Current Handling : Maximum output current of 1.2A may be insufficient for high-torque applications
- Heat Dissipation : Requires proper thermal management in continuous high-load operations
- Frequency Constraints : Fixed internal oscillator limits customization of switching frequency
- Component Count : Still requires external Hall sensors for position detection
## 2. Design Considerations
### Common Design Pitfalls and Solutions
Pitfall 1: Inadequate Decoupling
- Problem : Motor noise coupling into power supply causing erratic operation
- Solution : Implement 100nF ceramic capacitor close to VCC pin and 10μF electrolytic capacitor near power input
Pitfall 2: Poor Thermal Management
- Problem : Overheating during continuous operation leading to thermal shutdown
- Solution :
- Use adequate copper pour for heat sinking
- Consider external heatsink for high ambient temperatures
- Implement thermal vias under package for improved heat transfer
Pitfall 3: EMI Issues
- Problem : Electromagnetic interference affecting nearby sensitive circuits
- Solution :
- Implement proper grounding techniques
- Use twisted pair wiring for motor connections
- Add ferrite beads on power input lines
### Compatibility Issues with Other Components
Hall Sensor Integration
- Requires bipolar Hall sensors with open-collector outputs
- Compatible sensors: DN6851, A3141 series
- Ensure proper pull-up resistors (typically 10kΩ) on Hall sensor outputs
Microcontroller Interface
- Compatible with : 3.3V and 5V logic families
- FG Output : Requires pull-up resistor when interfacing with microcontroller
- Standby Control : Compatible with CMOS/TTL logic levels
Power Supply Requirements
- Sensitive to : Power supply ripple exceeding 100mVpp
- Requires : Stable DC supply with less than 5% voltage variation
- Incompatible with : Switching regulators having high-frequency noise without proper filtering
### PCB Layout Recommendations
Power Section Layout
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1. Place bulk capacitors (100
