BP87112
High-performance flyback PWM controller with integrated 700V MOSFET for adapter applications up to 24W
Product Overview
Description
The BP87112 is a high-efficiency flyback PWM controller with integrated 700V power MOSFET designed for power adapter and charger applications. It features optimized PWM control for high efficiency across load conditions.
This controller supports universal AC input (85V-265V) and provides accurate constant voltage and constant current regulation. The built-in frequency dithering function helps reduce EMI and simplify filter design.
Advanced protection features include over-voltage protection, over-current protection, short-circuit protection, and over-temperature protection. The BP87112 achieves low standby power consumption below 75mW.
Product Series
BP
Primary Application
Mobile chargers
Key Features
- Integrated 700V power MOSFET
- High-efficiency PWM control
- Frequency dithering for EMI reduction
- Low standby power <75mW
- CV/CC regulation
- Comprehensive protection
Specifications
| Input Voltage | 85V-265V AC |
|---|---|
| Output Power | Up to 24W |
| Integrated MOSFET | 700V |
| Switching Frequency | 65kHz |
| Standby Power | <75mW |
| CV Accuracy | ±1% |
| CC Accuracy | ±5% |
| Package | SOP-8 |
Applications
Mobile chargers
Battery and charging management
Power adapters
Electronic system design
Appliance power supplies
Electronic system design
Auxiliary power
Electronic system design
Consumer electronics
Consumer electronics
FAE Expert Insights
"The BP87112 is an excellent choice for cost-effective adapter designs up to 24W. The integrated 700V MOSFET eliminates the need for external power switches, reducing BOM cost and PCB area. In my experience with multiple adapter designs, the built-in frequency dithering significantly reduces EMI, often allowing simpler filter designs that pass CISPR22/EN55022 with margin. The CV/CC regulation accuracy is good enough for most consumer applications. I recommend this part for mobile chargers and small power adapters where cost is critical. For higher power or better efficiency, consider BPSemi's QR controller series."
Cost-effective flyback solution with integrated MOSFET and good EMI performance
— Steven Liu, BeiLuo
Frequently Asked Questions
What is the maximum output power of BP87112?
The BP87112 supports maximum output power of 24W under typical operating conditions with adequate thermal management. The actual maximum power depends on input voltage, thermal conditions, and efficiency requirements. At low input voltages (85V-110V), the maximum power may be limited by current ratings. For reliable operation, it is recommended to operate at 80% of maximum rated power with proper heatsinking and thermal design.
For applications above 20W, verify thermal performance or consider BP87113 with higher power rating.
How does the frequency dithering function work?
Frequency dithering modulates the switching frequency around the nominal value (typically ±5-10%) to spread EMI energy across a wider frequency band, reducing peak emissions. This helps meet EMI standards like CISPR22/EN55022 with simpler and lower-cost filter components. The BP87112 implements this function automatically without external components. The dithering is typically disabled at light loads to maintain efficiency in burst mode operation.
Enable frequency dithering for EMI-sensitive applications. Contact LiTong for EMI filter design guidance.
What is the difference between CV and CC regulation modes?
CV (Constant Voltage) mode maintains a fixed output voltage regardless of load current, suitable for most electronic devices. CC (Constant Current) mode maintains a fixed output current, typically used for battery charging or LED driving. The BP87112 automatically switches between CV and CC modes: CV mode operates under normal load conditions, while CC mode activates when the load attempts to draw current above the set limit. This dual-mode operation makes the controller suitable for both adapter and charger applications.
Configure CV/CC setpoints based on application requirements. Contact LiTong for CV/CC design guidance.
How do I optimize efficiency with BP87112?
Efficiency optimization strategies for BP87112: 1) Use synchronous rectification for output currents above 2A, 2) Optimize transformer design for minimal copper and core losses, 3) Select low-Rds(on) external MOSFET if using non-integrated version, 4) Use appropriate inductance for CCM operation at full load, 5) Minimize snubber losses while maintaining voltage stress limits, 6) Optimize feedback network for stability without excessive power consumption. BPSemi provides efficiency optimization guidelines and reference designs.
Follow BPSemi efficiency optimization guidelines or contact LiTong for design review and optimization support.
What startup circuit design is recommended?
The BP87112 startup circuit typically uses a high-value startup resistor (1M-10M ohm) from the rectified DC bus to the VCC pin. After startup, the auxiliary winding supplies VCC power. For ultra-low standby power designs, consider using a depletion mode MOSFET or active startup circuit. The startup resistor value affects startup time and standby power - higher values reduce standby power but increase startup time. BPSemi reference designs provide optimized startup circuit configurations.
Use BPSemi reference startup circuit or contact LiTong for ultra-low standby power startup design.