Overview
The NCP1377P, 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 any load/line conditions. It features minimum drain voltage switching due to its quasi-resonant operation. The NCP1377P also includes an inherent skip cycle capability, which allows the controller 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 (Tss) | - | 1.0 | - | ms |
| Sampling Time | - | 4.5 | - | µs (NCP1377), 1.5 µs (NCP1377B) |
| Internal Blanking Delay After TON (Tblank) | - | 8.0 | - | µs (NCP1377), 3.0 µs (NCP1377B) |
| Maximum Junction Temperature (TJMAX) | - | - | 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 |
Key Features
- Free-Running Borderline/Critical Mode Quasi-Resonant Operation: Ensures minimum drain voltage switching and reduced EMI/video noise perturbations.
- Latched Overvoltage Protection (OVP): The IC permanently latches off upon detecting an overvoltage condition.
- Auto-Recovery Short-Circuit Protection via UVLO Crossover: Disables output pulses and enters a safe burst mode during overcurrent conditions, auto-recovering 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: Tailors the level at which the skip cycle takes place, ensuring noise-free operation.
- Internal 1ms Soft-Start: Eliminates traditional startup stress.
- Internal Temperature Shutdown: Protects the device from overheating.
- Transformer Core Reset Detection: Ensures borderline/critical operation and reduces primary switch turn-on losses and secondary diode recovery losses.
Applications
The NCP1377P 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 candidate for building rugged and reliable Switchmode Power Supplies (SMPS).
Q & A
- What is the primary function of the NCP1377P?
The NCP1377P is a PWM Current-Mode Controller designed for free-running quasi-resonant operation in switchmode power supplies.
- How does the NCP1377P handle overvoltage conditions?
The NCP1377P features latched overvoltage protection, which permanently latches off the IC upon detecting an overvoltage condition.
- What is the purpose of the internal soft-start feature?
The internal 1ms soft-start eliminates traditional startup stress and ensures a smooth startup sequence.
- How does the skip cycle capability work?
The skip cycle capability allows the controller to enter burst mode when power demand falls below a predetermined level, ensuring noise-free operation at low peak current.
- What is the significance of the demagnetization detector?
The demagnetization detector ensures full borderline/critical Conduction Mode and reduces primary switch turn-on losses and secondary diode recovery losses.
- How does the NCP1377P protect against short circuits?
The NCP1377P disables output pulses and enters a safe burst mode during short-circuit conditions, auto-recovering once the fault is cleared.
- What are the typical applications of the NCP1377P?
The NCP1377P is used in low-cost AC-DC adapters, consumer electronics, and auxiliary power supplies.
- What is the maximum junction temperature for the NCP1377P?
The maximum junction temperature is 150°C.
- How does the NCP1377P handle temperature shutdown?
The NCP1377P features internal temperature shutdown, which protects the device from overheating.
- What is the ESD capability of the NCP1377P?
The ESD capability, according to the HBM model, is 2.0 kV.
