Overview
The NCP1377BDR2G, produced by onsemi, is a PWM Current-Mode Controller designed for free-running quasi-resonant operation. This controller combines a true current-mode modulator and a demagnetization detector, ensuring full borderline/critical conduction mode in various load and line conditions. It features minimum drain voltage switching and quasi-resonant operation, which reduces EMI and video noise perturbations. The NCP1377BDR2G is particularly suited for low-cost AC-DC adapters, consumer electronics, and auxiliary power supplies due to its high-performance high-voltage technology and low part count.
Key Specifications
| Characteristic | Min | Typ | Max | Unit |
|---|---|---|---|---|
| Internal Timer Duration | - | 3.0 | - | μs |
| Maximum Junction Temperature | - | - | 150 | °C |
| Temperature Shutdown | - | - | 155 | °C |
| Storage Temperature Range | -60 | - | 150 | °C |
| ESD Capability (HBM Model) | - | - | 2.0 | kV |
| Maximum Voltage on Pin 8 (HV) | - | - | 500 | V |
| Output Voltage Rise-Time @ CL = 1.0 nF | 40 | - | - | ns |
| Output Voltage Fall-Time @ CL = 1.0 nF | 20 | - | - | ns |
| Source Resistance | 12 | 20 | 36 | Ω |
| Sink Resistance | 5.0 | 10 | 19 | Ω |
| Internal Current Setpoint | 0.9 | 1.0 | 1.1 | V |
| Soft-Start Time | - | 1.0 | - | ms |
Key Features
- Free-Running Borderline/Critical Mode Quasi-Resonant Operation: Ensures efficient operation with minimal primary switch turn-on losses and secondary diode recovery losses.
- Latched Overvoltage Protection (OVP): The IC latches off permanently upon detecting an overvoltage condition, requiring a power cycle to reset.
- Auto-Recovery Short-Circuit Protection: The device enters a safe burst mode during short-circuit conditions and auto-recovers once the fault is cleared.
- External Latch Triggering: Allows external signals, such as from a temperature sensor, to latch off the IC.
- Current-Mode with Adjustable Skip Cycle Capability: The skip cycle level can be adjusted to optimize performance under varying load conditions.
- Internal 1.0 ms Soft-Start: Reduces startup stress and ensures a smooth power-up sequence.
- Internal Temperature Shutdown: Protects the device from overheating by shutting down at high temperatures.
- Transformer Core Reset Detection: Ensures borderline/critical conduction mode operation and reduces EMI.
Applications
The NCP1377BDR2G is ideal for various applications, including:
- Low-Cost AC-DC Adapters: Due to its high-performance and low part count, it is well-suited for cost-sensitive designs.
- Consumer Electronics: Suitable for power supplies in consumer electronics where efficiency and reliability are crucial.
- Auxiliary Power Supplies: Used in auxiliary power supplies where compact design and high efficiency are required.
Q & A
- What is the primary function of the NCP1377BDR2G?
The NCP1377BDR2G is a PWM Current-Mode Controller designed for free-running quasi-resonant operation in switch-mode power supplies.
- What is the significance of the demagnetization detector in the NCP1377BDR2G?
The demagnetization detector ensures borderline/critical conduction mode operation, reducing primary switch turn-on losses and secondary diode recovery losses.
- How does the NCP1377BDR2G handle overvoltage conditions?
The IC features latched overvoltage protection, which permanently latches off the device upon detecting an overvoltage condition, requiring a power cycle to reset.
- What is the purpose of the internal soft-start feature?
The internal 1.0 ms soft-start reduces startup stress and ensures a smooth power-up sequence.
- How does the NCP1377BDR2G protect against short-circuit conditions?
The device enters a safe burst mode during short-circuit conditions and auto-recovers once the fault is cleared.
- Can the skip cycle level be adjusted in the NCP1377BDR2G?
Yes, the skip cycle level can be adjusted to optimize performance under varying load conditions.
- What is the maximum junction temperature for the NCP1377BDR2G?
The maximum junction temperature is 150°C.
- How does the NCP1377BDR2G handle temperature shutdown?
The device shuts down at temperatures above 155°C to protect against overheating.
- What are the typical applications of the NCP1377BDR2G?
The NCP1377BDR2G is used in low-cost AC-DC adapters, consumer electronics, and auxiliary power supplies.
- What is the significance of the internal timer in the NCP1377BDR2G?
The internal timer prevents the switching frequency from exceeding 300 kHz and avoids false leakage inductance tripping at turn-off.
