Overview
The NCP1217D100R2G, produced by onsemi, is an enhanced PWM controller designed for high-performance AC/DC converters. It is housed in an SO-8 package and represents an advanced version of the NCP1203-based controllers. This device is notable for its high drive capability, allowing it to drive large gate-charge MOSFETs, and features internal ramp compensation and built-in overvoltage protection. The NCP1217D100R2G operates at a fixed frequency of 100 kHz and is an excellent alternative to UC384X-based designs.
Key Specifications
| Parameter | Min | |||
|---|---|---|---|---|
| Oscillation Frequency (100 kHz Version) | 90 | 100 | 110 | kHz |
| Maximum Duty-Cycle (NCP1217) | 69 | 74 | 80 | % |
| Maximum Duty-Cycle (NCP1217A) | 42 | 46.5 | 50 | % |
| Peak Current Capability | - | - | 500 | mA |
| Internal Soft-Start Time (NCP1217A Only) | - | 1.0 | - | ms |
| Maximum Junction Temperature | - | - | 150 | °C |
| Storage Temperature Range | -60 | - | 150 | °C |
| ESD Capability (HBM Model) | - | - | 2.0 | kV |
Key Features
- Current-Mode Control with Adjustable Skip-Cycle Capability: The NCP1217 features a current-mode control topology with the ability to adjust the skip cycle level, ensuring efficient operation at light loads and preventing acoustic noise.
- Built-in Internal Ramp Compensation: This feature prevents subharmonic oscillations in continuous conduction mode designs by injecting a controlled amount of ramp compensation.
- Auto-Recovery Internal Output Short-Circuit Protection: The device enters a safe burst mode in case of an overcurrent condition and auto-recovers once the fault is cleared.
- Internal 1.0 ms Soft-Start (NCP1217A Only): Ensures a smooth startup sequence.
- Limited Duty-Cycle to 50% (NCP1217A Only): Restricts the maximum duty cycle to 50% for specific applications.
- Full Latchoff if Adjustment Pin is Brought High: Allows for external latchoff control by bringing the adjustment pin above a specified voltage.
- Extremely Low No-Load Standby Power: Optimized for low power consumption during standby.
- Internal Temperature Shutdown: Protects the device from overheating by shutting down at high temperatures.
- Direct Optocoupler Connection: Simplifies the feedback loop setup.
- Internal Leading Edge Blanking: Enhances the stability of the switching operation.
- SPICE Models Available: For transient and AC analysis.
Applications
- High Power AC/DC Converters for TVs, Set-Top Boxes, etc.: Ideal for high-power conversion needs in consumer electronics.
- Offline Adapters for Notebooks: Suitable for power adapters requiring high efficiency and reliability.
- Telecom DC-DC Converters: Used in telecommunications equipment for efficient power conversion.
- All Power Supplies: General-purpose use in various power supply applications.
Q & A
- What is the primary function of the NCP1217D100R2G?
The NCP1217D100R2G is a PWM controller designed for high-performance AC/DC converters, operating in current-mode control with adjustable skip-cycle capability.
- What are the fixed frequency versions available for the NCP1217?
The NCP1217 is available in fixed frequency versions of 65 kHz, 100 kHz, and 133 kHz.
- How does the NCP1217 handle overcurrent conditions?
In case of an overcurrent condition, the device enters a safe burst mode and auto-recovers once the fault is cleared.
- What is the purpose of the internal ramp compensation in the NCP1217?
The internal ramp compensation prevents subharmonic oscillations in continuous conduction mode designs by injecting a controlled amount of ramp compensation.
- How does the skip cycle mode work in the NCP1217?
The NCP1217 automatically skips switching cycles when the output power demand drops below a given level, ensuring efficient operation at light loads and preventing acoustic noise.
- What is the maximum junction temperature for the NCP1217?
The maximum junction temperature for the NCP1217 is 150°C.
- Does the NCP1217 have built-in temperature shutdown protection?
Yes, the NCP1217 has internal temperature shutdown protection to prevent overheating.
- How does the NCP1217 ensure a clean startup sequence?
The NCP1217 features a high-voltage startup FET that ensures a clean and lossless startup sequence by injecting a constant current into the VCC capacitor during startup.
- What is the typical storage temperature range for the NCP1217?
The storage temperature range for the NCP1217 is -60°C to 150°C.
- Is the NCP1217 ESD protected?
Yes, the NCP1217 has ESD protection rated using the Human Body Model (HBM) and Machine Model (MM).
