Overview
The NCP1377D1R2G, 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, which is characteristic of quasi-resonant operation. The NCP1377D1R2G is particularly suited for applications where low part count and high reliability are crucial, such as in low-cost AC-DC adapters, consumer electronics, and auxiliary power supplies.
Key Specifications
| Characteristic | Min | Typ | Max | Unit |
|---|---|---|---|---|
| Internal Timer Duration (NCP1377) | - | 8.0 | - | μs |
| Internal Timer Duration (NCP1377B) | - | 3.0 | - | μs |
| Sampling Time (NCP1377) | - | 4.5 | - | μs |
| Sampling Time (NCP1377B) | - | 1.5 | - | μs |
| Maximum Junction Temperature | - | - | 150 | °C |
| Temperature Shutdown | - | - | 155 | °C |
| Storage Temperature Range | -60 | - | 150 | °C |
| ESD Capability (HBM Model) | - | - | 2.0 | kV |
| 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 |
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 permanently latches off upon detecting an overvoltage condition, ensuring protection until the power supply is cycled down.
- Auto-Recovery Short-Circuit Protection via UVLO Crossover: Automatically recovers from short-circuit conditions by stopping switching pulses and attempting to restart 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: Enables skip cycle operation to reduce power consumption at low output power conditions.
- Internal 1.0 ms Soft-Start: Reduces startup stress and ensures a smooth startup sequence.
- Internal Temperature Shutdown: Protects the IC from overheating by shutting down at high temperatures.
- Internal Leading Edge Blanking: Prevents false triggering due to noise spikes.
- Transformer Core Reset Detection: Ensures borderline/critical conduction mode operation through demagnetization detection.
Applications
The NCP1377D1R2G is ideal for various applications where high efficiency, reliability, and low component count are essential. These include:
- Low-cost AC-DC adapters
- Consumer electronics
- Auxiliary power supplies
- Switchmode Power Supplies (SMPS)
Q & A
- What is the primary function of the NCP1377D1R2G?
The NCP1377D1R2G is a PWM Current-Mode Controller designed for free-running quasi-resonant operation in switchmode power supplies.
- What is the significance of the quasi-resonant operation mode?
Quasi-resonant operation ensures efficient switching by restarting the MOSFET at the minimum of the drain-source wave, reducing EMI and video noise perturbations.
- How does the NCP1377D1R2G handle overvoltage protection?
The IC features latched overvoltage protection, which permanently latches off the IC upon detecting an overvoltage condition until the power supply is cycled down.
- What is the purpose of the internal soft-start feature?
The internal 1.0 ms soft-start reduces startup stress and ensures a smooth startup sequence.
- How does the NCP1377D1R2G handle short-circuit conditions?
The IC automatically recovers from short-circuit conditions by stopping switching pulses and attempting to restart once the fault is cleared.
- What is the maximum junction temperature for the NCP1377D1R2G?
The maximum junction temperature is 150°C.
- What is the storage temperature range for the NCP1377D1R2G?
The storage temperature range is from -60°C to 150°C.
- How does the skip cycle capability work in the NCP1377D1R2G?
The skip cycle capability allows the controller to skip switching cycles at low output power conditions, reducing power consumption.
- What is the role of the demagnetization detection in the NCP1377D1R2G?
Demagnetization detection ensures borderline/critical conduction mode operation by triggering the turn-on event based on the transformer core reset.
- What are some typical applications for the NCP1377D1R2G?
Typical applications include low-cost AC-DC adapters, consumer electronics, auxiliary power supplies, and switchmode power supplies (SMPS).
