Overview
The NCP1337DR2G, produced by onsemi, is a PWM Current-Mode Controller designed for free-running quasi-resonant operation. This controller combines a true current-mode modulator with a demagnetization detector, ensuring full Borderline/Critical Conduction Mode in various load and line conditions. It features minimum drain voltage switching and internal transformer core reset detection without the need for external signals, thanks to the Soxyless concept. The NCP1337DR2G is optimized for high-performance, high-voltage applications and includes several protective and operational features to enhance reliability and efficiency in switch-mode power supplies (SMPS).
Key Specifications
| Characteristic | Symbol | Min | Typ | Max | Unit |
|---|---|---|---|---|---|
| Maximum Frequency | - | - | 130 | kHz | |
| Minimum Switching Frequency | - | - | 25 | kHz | |
| Maximum Current in Pin 8 (HV) | - | - | 20 | mA | |
| Power Supply Voltage, Pin 6 (VCC) | VCCmax | -0.3 | - | 20 | V |
| Maximum Current in Pin 6 (VCC) | - | - | ±30 | mA | |
| Maximum Junction Temperature | TJMAX | - | - | 150 | °C |
| Operating Temperature Range | - | -40 | - | 125 | °C |
| Internal Soft-Start Duration | TSS | - | 4.0 | - | ms |
| Temperature Shutdown | TSD | - | 130 | - | °C |
Key Features
- Free-Running Borderline/Critical Mode Quasi-Resonant Operation: Ensures valley-switching operation under all load and line conditions, reducing primary switch turn-on losses and secondary diode recovery losses.
- Soft-Skip Mode: Enters skip mode when power demand falls below a predetermined level, ensuring noise-free operation with a minimum switching frequency.
- Auto-Recovery Short-Circuit Protection: Disables output pulses and enters a safe burst mode in case of overcurrent conditions, with automatic recovery once the fault is cleared.
- Overvoltage Protection (OVP): Stops switching when an overvoltage condition is detected on the VCC voltage level.
- Brown-Out Detection (BO): Protects against low mains conditions by monitoring the level on Pin 1 and stopping switching until the level returns to normal.
- Internal 4.0 ms Soft-Start: Eliminates startup stress and ensures smooth startup sequences.
- Dynamic Self-Supply (DSS): Allows direct connection to the high-voltage DC rail, simplifying VCC capacitor selection and eliminating the need for an auxiliary winding in low-power applications.
- Two Externally Triggerable Fault Comparators: One for disable function and the other for permanent latch.
- Internal Temperature Shutdown: Protects the device from overheating.
- Direct Optocoupler Connection: Simplifies the design of primary regulation.
Applications
- AC-DC Adapters for Notebooks and Other Devices: Ideal for low-cost, high-efficiency power supplies.
- Offline Battery Chargers: Suitable for charging applications requiring reliable and efficient power conversion.
- Consumer Electronics: Used in devices such as DVD players, set-top boxes, and other consumer electronics requiring efficient and reliable power supplies.
- Auxiliary Supplies: Applicable in various auxiliary power supply scenarios where high performance and reliability are crucial.
Q & A
- What is the maximum operating frequency of the NCP1337DR2G?
The maximum operating frequency is 130 kHz.
- How does the NCP1337DR2G handle overcurrent conditions?
The device disables output pulses and enters a safe burst mode, attempting to restart after the fault is cleared.
- What is the purpose of the Soft-Skip mode in the NCP1337DR2G?
The Soft-Skip mode ensures noise-free operation by stopping output pulses when the power demand falls below a predetermined level and restarting switching when the feedback loop requires a higher setpoint.
- How does the NCP1337DR2G protect against overvoltage conditions?
The device stops switching when an overvoltage condition is detected on the VCC voltage level.
- What is the function of the Dynamic Self-Supply (DSS) in the NCP1337DR2G?
The DSS allows direct connection to the high-voltage DC rail, simplifying VCC capacitor selection and eliminating the need for an auxiliary winding in low-power applications.
- What is the internal soft-start duration of the NCP1337DR2G?
The internal soft-start duration is 4.0 ms.
- How does the NCP1337DR2G handle temperature extremes?
The device features internal temperature shutdown to protect against overheating, with a shutdown temperature of 130°C.
- What are the typical applications of the NCP1337DR2G?
Typical applications include AC-DC adapters, offline battery chargers, consumer electronics, and auxiliary supplies.
- How does the NCP1337DR2G protect against brown-out conditions?
The device monitors the level on Pin 1 and stops switching until the level returns to normal, protecting against low mains conditions.
- What is the maximum junction temperature of the NCP1337DR2G?
The maximum junction temperature is 150°C.
