Overview
The NCP1217P100G, produced by Onsemi, is a high-performance PWM controller designed for fixed-frequency, current-mode operation. It is an enhanced version of the NCP1203-based controllers and is housed in either an SOIC-8 or PDIP-7 package. This controller is ideal for applications requiring low part-count and high efficiency, particularly in low-cost AC/DC adapters, TV power supplies, and other high-power AC/DC converters.
The NCP1217P100G features a high-voltage startup FET, internal ramp compensation, and built-in overvoltage protection, making it a robust solution for modern power supply designs. It operates at fixed frequencies of 65 kHz, 100 kHz, and 133 kHz, and offers excellent input audio-susceptibility and pulse-by-pulse control.
Key Specifications
| Parameter | Min | |||
|---|---|---|---|---|
| Oscillation Frequency (65 kHz Version) | 58.5 | 65 | 71.5 | kHz |
| Oscillation Frequency (100 kHz Version) | 90 | 100 | 110 | kHz |
| Oscillation Frequency (133 kHz Version) | 120 | 133 | 146 | kHz |
| Maximum Duty-Cycle (NCP1217) | 69 | 74 | 80 | % |
| Maximum Duty-Cycle (NCP1217A) | 42 | 46.5 | 50 | % |
| Peak Current Capability | 500 | mA | ||
| Maximum Junction Temperature | 150 | °C | ||
| Storage Temperature Range | -60 | 150 | °C | |
| ESD Capability (HBM Model) | 2.0 | kV | ||
| ESD Capability (Machine Model) | 200 | V |
Key Features
- Current-Mode with Adjustable Skip-Cycle Capability: The NCP1217 allows for adjustable skip cycle operation to enhance efficiency at light loads.
- Built-in Internal Ramp Compensation: Prevents subharmonic oscillations in continuous conduction mode designs.
- 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 duty cycle to 50% for specific applications.
- Full Latchoff if Adjustment Pin is Brought High: Allows for external control to shut down the device.
- Extremely Low No-Load Standby Power: Reduces power consumption during no-load conditions.
- Internal Temperature Shutdown: Protects the device from overheating.
- Direct Optocoupler Connection: Simplifies the feedback loop design.
- Internal Leading Edge Blanking: Enhances noise immunity.
- SPICE Models Available: For transient and AC analysis.
Applications
- High Power AC/DC Converters: Suitable for TVs, set-top boxes, and other high-power applications.
- Offline Adapters for Notebooks: Ideal for low-cost, high-efficiency power adapters.
- Telecom DC-DC Converters: Used in various telecom power supply applications.
- All Power Supplies: General-purpose use in a wide range of power supply designs.
Q & A
- What are the fixed frequency options for the NCP1217?
The NCP1217 operates at fixed frequencies of 65 kHz, 100 kHz, and 133 kHz.
- What is the purpose of the internal ramp compensation in the NCP1217?
The internal ramp compensation prevents subharmonic oscillations in continuous conduction mode designs.
- 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 maximum duty cycle for the NCP1217 and NCP1217A?
The maximum duty cycle for the NCP1217 is 74%, and for the NCP1217A, it is 50%.
- How does the NCP1217 reduce no-load standby power?
The NCP1217 reduces no-load standby power by skipping unwanted switching cycles at low power levels.
- What is the peak current capability of the NCP1217?
The peak current capability of the NCP1217 is 500 mA.
- 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 overvoltage protection?
Yes, the NCP1217 has built-in overvoltage protection that shuts down the device if the adjustment pin is brought above a certain voltage threshold.
- Can the NCP1217 be used in telecom DC-DC converters?
Yes, the NCP1217 is suitable for use in telecom DC-DC converters.
- Is the NCP1217 Pb-free?
Yes, the NCP1217 is a Pb-free device.
