Overview
The NCP1377BP, produced by onsemi, is a PWM Current-Mode Controller designed for free-running quasi-resonant operation. It combines a true current mode modulator with a demagnetization detector, ensuring full borderline/critical Conduction Mode in various load and line conditions. This controller minimizes drain voltage switching through quasi-resonant operation, reducing EMI and noise perturbations. The NCP1377BP features an inherent skip cycle capability, which allows it to enter burst mode when power demand falls below a predetermined level, eliminating audible noise at low peak current.
Key Specifications
| Characteristic | Min | Typ | Max | Unit |
|---|---|---|---|---|
| Internal Soft-Start Time | - | 1.0 | - | ms |
| Sampling Time (NCP1377) | - | 4.5 | - | µs |
| Sampling Time (NCP1377B) | - | 1.5 | - | µs |
| Internal Blanking Delay After TON (NCP1377) | - | 8.0 | - | µs |
| Internal Blanking Delay After TON (NCP1377B) | - | 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 |
| ESD Capability (Machine Model) | - | - | 200 | V |
Key Features
- Free-Running Borderline/Critical Mode Quasi-Resonant Operation: Ensures minimal drain voltage switching and reduced EMI/video noise perturbations.
- Latched Overvoltage Protection (OVP): The IC permanently latches off upon detecting an overvoltage condition and remains in this state until the Vcc is cycled down to 4.0 V.
- Auto-Recovery Short-Circuit Protection via UVLO Crossover: The device enters a safe burst mode and attempts to restart upon detecting an overcurrent condition.
- External Latch Triggering: Allows external signals, such as from a temperature sensor, to latch off the IC.
- Current-Mode with Adjustable Skip Cycle Capability: Enables the selection of the frequency at which the burst foldback takes place, ensuring noise-free operation.
- Internal 1.0 ms Soft-Start: Eliminates traditional startup stress.
- Internal Temperature Shutdown: Protects the device from overheating.
- Transformer Core Reset Detection: Ensures borderline/critical operation in any load/line conditions, minimizing primary switch turn-on losses and secondary diode recovery losses.
Applications
The NCP1377BP is particularly suited for low-cost AC-DC adapters, consumer electronics, and auxiliary power supplies. Its high-performance, high-voltage technology makes it an ideal choice for building rugged and reliable Switchmode Power Supplies (SMPS).
Q & A
- What is the primary function of the NCP1377BP?
The NCP1377BP is a PWM Current-Mode Controller designed for free-running quasi-resonant operation in switchmode power supplies.
- How does the NCP1377BP handle overvoltage conditions?
The IC features latched overvoltage protection, which permanently latches off the device upon detecting an overvoltage condition until the Vcc is cycled down to 4.0 V.
- What is the purpose of the internal soft-start feature?
The internal 1.0 ms soft-start eliminates traditional startup stress and ensures a smooth startup sequence.
- How does the NCP1377BP manage temperature?
The device includes internal temperature shutdown to protect it from overheating, with a shutdown temperature of 155°C.
- What is the significance of the skip cycle capability in the NCP1377BP?
The skip cycle capability allows the controller to enter burst mode at low peak current, ensuring noise-free operation and adjustable switching frequencies.
- How does the NCP1377BP handle short-circuit conditions?
The device enters a safe burst mode and attempts to restart upon detecting a short-circuit condition, ensuring auto-recovery once the fault is cleared.
- What are the typical applications of the NCP1377BP?
The NCP1377BP is used in low-cost AC-DC adapters, consumer electronics, and auxiliary power supplies.
- What is the maximum junction temperature for the NCP1377BP?
The maximum junction temperature is 150°C.
- How does the NCP1377BP protect against ESD?
The device has an ESD capability of 2.0 kV for the HBM model and 200 V for the machine model.
- What is the storage temperature range for the NCP1377BP?
The storage temperature range is from -60°C to 150°C.
