Overview
The NCP1937A2DR2G from onsemi is a highly integrated power management IC that combines power factor correction (PFC) and quasi-resonant flyback controller functionalities. This device is designed to implement compact and highly efficient switched-mode power supplies, particularly for adapter applications. It features a critical conduction mode PFC stage with near-unity power factor and a quasi-resonant flyback stage with valley-lockout circuitry to ensure stable and noise-free operation. The IC also includes various protection mechanisms and power-saving features to enhance efficiency and reliability.
Key Specifications
| Parameter | Value | Unit |
|---|---|---|
| VCC Range | 9 to 30 | V |
| Output Current (Source/Sink) | 0.5 A / 0.8 A | A |
| Package Type | SOIC-20 Narrow Body | - |
| Operating Voltage Range | 8.8 to 30 | V DC |
| PFC Frequency Clamp | 131 kHz | kHz |
| Overload Protection | Auto-Recovery, Latch | - |
| Brown-out Detection Thresholds | 111 V (start), 101 V (stop) | V |
| Maximum Off Time | 100 to 1300 μs | μs |
Key Features
- Critical Conduction Mode (CrM) PFC with constant on-time control and maximum frequency clamp.
- Quasi-resonant flyback stage with valley-lockout circuitry for noise-free operation.
- High-voltage startup circuit and active input filter capacitor discharge circuitry.
- Integrated high-voltage brown-out detector and high-voltage switch to reduce standby power.
- Fault input for severe fault conditions with NTC compatibility (Latch and Auto-Recovery options).
- Internal temperature shutdown and power savings mode to reduce supply current consumption.
- Adjustable PFC disable threshold based on output power and feed-forward for improved operation across line and load.
- Timer-based overload protection and adjustable overpower protection.
- Winding and output diode short-circuit protection.
- 4 ms soft-start timer and skip mode operation for excellent efficiency in light load conditions.
Applications
The NCP1937A2DR2G is primarily designed for use in compact and highly efficient switched-mode power supplies, particularly for adapter applications. It is suitable for a variety of power supply designs that require high efficiency, low standby power, and robust protection features.
- Power adapters for consumer electronics.
- Switched-mode power supplies requiring high power factor correction.
- Efficient power solutions for industrial and medical devices.
Q & A
- What is the primary function of the NCP1937A2DR2G?
The NCP1937A2DR2G is a combination power factor correction (PFC) and quasi-resonant flyback controller designed for implementing compact and highly efficient switched-mode power supplies.
- What is the operating voltage range of the NCP1937A2DR2G?
The operating voltage range is from 8.8 V to 30 V DC.
- What type of package does the NCP1937A2DR2G come in?
The NCP1937A2DR2G comes in a SOIC-20 Narrow Body package.
- What are the key protection features of the NCP1937A2DR2G?
The IC includes features such as internal temperature shutdown, brown-out detection, fault input for severe fault conditions, and winding and output diode short-circuit protection.
- How does the NCP1937A2DR2G achieve high efficiency in light load conditions?
The device achieves high efficiency in light load conditions through skip mode operation and a power savings mode that reduces supply current consumption.
- What is the purpose of the valley-lockout circuitry in the quasi-resonant flyback stage?
The valley-lockout circuitry ensures stable valley switching and eliminates audible noise by toggling to a frequency foldback mode beyond the 4th valley.
- Can the NCP1937A2DR2G be used in industrial applications?
- How does the PFC stage operate in the NCP1937A2DR2G?
The PFC stage operates in Critical Conduction Mode (CrM) with constant on-time control and a maximum frequency clamp, ensuring near-unity power factor.
- What is the significance of the high-voltage startup circuit in the NCP1937A2DR2G?
The high-voltage startup circuit helps in discharging the input filter capacitors and reducing standby power consumption.
- Can the NCP1937A2DR2G be configured for different overload protection modes?
