In-depth Analysis of BM2P0161-Z High-performance AC/DC Converter
1. One-sentence Description
The BM2P0161-Z is a PWM-type AC/DC converter integrating a 730V startup circuit and a switching MOSFET, specifically designed for low-power electrical appliances. It supports isolated/non-isolated topologies and features high efficiency and wide voltage adaptability.
2. Core Features
- Full-mode Control: Adopting PWM current mode control, it supports frequency hopping (125Hz), burst operation (reducing power consumption under light load), and frequency adjustment (a typical value of 65kHz), optimizing efficiency and EMI.
- Multiple Protection Mechanisms: Integrated with VCC under-voltage/over-voltage protection, SOURCE pin open-circuit/short-circuit protection, soft start, over-current protection (including AC voltage compensation), and thermal shutdown functions.
- Flexible Design: An externally adjustable current detection resistor and FB pin feedback adjustment are suitable for various output specifications; a built-in 730V high-voltage-resistant MOSFET reduces the number of peripheral components.
- Low-power Optimization: Smart charging management for the VCC pin, burst operation mode under light load, and frequency reduction function make the standby power consumption lower than 3mW (when the input voltage is 240V).
3. Core Technical Indicators
| Parameter | Typical Value/Range | Remarks |
|---|---|---|
| Input Voltage | 8.9V~26V (VCC) | Supports wide voltage input |
| Output Withstand Voltage | 730V (DRAIN) | Can withstand a maximum pulse voltage of 730V |
| Quiescent Current | 0.65mA (Typ) | Low standby power consumption |
| Switching Frequency | 65kHz (Typ) | Can be adjusted through the FADJ pin |
| Efficiency | >85% (Typical Load) | Optimizes magnetic loss and conduction loss |
| Operating Temperature | -40°C~+105°C | Adapts to harsh environments |
4. The Story Behind the Chip
The BM2P0161-Z was born out of the industry trend of home appliance intelligence and energy efficiency upgrade. Aiming at the problems of traditional AC/DC converters such as high standby power consumption, serious EMI interference, and complex design, ROHM solves these pain points through the following innovations:
- 730V Startup Circuit: Replaces the traditional discrete solution, shortens the startup time (<0.1s@10μF), and reduces standby energy consumption.
- Integrated Design: Packages the MOSFET, control logic, and protection module into one, reducing the number of peripheral components (only a few resistors and capacitors are needed).
- Patented Protection Technology: For example, the LEB (Leading Edge Blanking) blanking technology eliminates switching transient interference, and the VSOURCE compensation algorithm improves the accuracy of over-current protection.
5. Design Concept
The BM2P0161-Z adheres to the trinity concept of "High Reliability × Simple Design × Green Energy Conservation":
- Reliability: Through multiple protections such as HBM ESD 4kV protection and thermal shutdown (TSD), it adapts to industrial-grade applications.
- Simplicity: Provides detailed reference circuits (such as the typical Flyback application diagram 15), and supports fast layout with DIP7K/DIP7WF dual packages.
- Environmental Friendliness: The frequency hopping function reduces EMI radiation and complies with international energy efficiency standards (such as CoC Tier2).
6. Application Scenarios
Widely used in consumer and industrial low-power devices:
- Home Appliance Field: Air conditioner remote controls, air purifiers, power modules of IH rice cookers.
- Consumer Electronics: Mobile phone/tablet chargers, Bluetooth speaker adapters.
- Industrial Control: Sensor power supply units, auxiliary power supplies for smart meters.
7. Unique Advantages
- Ultra-low Standby Power Consumption: Through VCC charging management and burst mode, it achieves industry-leading standby energy consumption at the 0.3mW level.
- Wide Voltage Tolerance: The DRAIN terminal can withstand a transient high voltage of 730V (10μs pulse), avoiding damage from lightning surges.
- Friendly Debugging: Provides detailed protection timing diagrams (Figure 4) and PCB heat dissipation design guidelines (Figure 14), shortening the R&D cycle.
8. What Engineers Must Know When Selecting
- Absolute Maximum Ratings: The VCC shall not exceed 32V, and the DRAIN pulse current should be lower than 12A (BM2P0161-Z).
- Key to Thermal Design: The recommended heat dissipation area of a single-layer PCB is ≥74.2mm×74.2mm, and it needs to be derated for use in high-temperature environments.
- Linkage of Protection Mechanisms: After the protection is triggered due to an abnormal FB pin voltage (>VFOLP1A for 128ms), it is necessary to wait for 332ms for reset.
- Package Compatibility: The DIP7WF version supports wave soldering, and attention should be paid to the pin pitch (2.54mm) and heat dissipation pad design.
Summary: The BM2P0161-Z, with its high integration, ultra-low power consumption, and strong adaptability, has become an ideal choice for small-power AC/DC conversion. Engineers can give full play to its performance advantages through precise parameter matching (such as setting the frequency hopping amplitude with CFADJ) and rigorous thermal design.
