Overview
The NCP1239BD100R2G is a fixed-frequency current-mode controller designed by onsemi, specifically tailored for flyback converter applications. This controller features a high-voltage start-up current source, which enables a quick and lossless power-on sequence, simplifying the design of the auxiliary supply and VCC capacitor. It operates at a fixed frequency of 100 kHz and includes various protection mechanisms and efficiency-enhancing features.
Key Specifications
| Parameter | Test Conditions | Min | Typ | Max | Unit |
|---|---|---|---|---|---|
| Switching Frequency | - | 96 | 100 | 104 | kHz |
| Start-Up Threshold (VCC) | VCC Increasing | 11.0 | 12.0 | 13.0 | V |
| Peak Sink Current (DRV Low State) | VDRV = VCC, CL = 1 nF | - | 500 | - | mA |
| High State Voltage (DRV) | VCC = 9 V, RDRV = 33 kΩ | - | 8.8 | - | V |
| Over-Voltage Protection Threshold (VFAULT) | VFAULT Increasing | 2.8 | 3.0 | 3.2 | V |
| Over-Temperature Protection Threshold (VFAULT) | VFAULT Decreasing | 0.37 | 0.40 | 0.43 | V |
| VCC Operation Range | - | - | - | 35 | V |
Key Features
- Fixed-Frequency 100-kHz Current-Mode Control Operation
- Frequency Foldback Down to 26 kHz and Skip Mode for Light Load Conditions
- Adjustable Over Power Protection (OPP) Circuit
- High-Voltage Current Source with Brown-Out (BO) Detection
- Internal Slope Compensation and Fixed Soft-Start
- Frequency Jittering in Normal and Frequency Foldback Modes
- 64-ms Timer-Based Short-Circuit Protection with Auto-Recovery or Latched Operation
- Latched OVP on VCC – Auto-Recovery for C and E Versions
- Latched OVP/OTP Input for Improved Robustness
- ±500 mA Peak Source/Sink Drive Capability
- Internal Thermal Shutdown
- Extremely Low No-Load Standby Power
- Pin-to-Pin Compatible with the Existing NCP1236/1247 Series
- Pb-Free and RoHS Compliant
Applications
- AC-DC Converters for TVs, Set-Top Boxes, and Printers
- Offline Adapters for Notebooks and Netbooks
Q & A
- What is the primary function of the NCP1239BD100R2G?
The NCP1239BD100R2G is a fixed-frequency current-mode controller designed for flyback converter applications.
- What is the switching frequency of the NCP1239BD100R2G?
The switching frequency is 100 kHz, with frequency foldback down to 26 kHz in light load conditions.
- What protection mechanisms does the NCP1239BD100R2G include?
The controller includes over-power protection (OPP), over-voltage protection (OVP), over-temperature protection (OTP), and short-circuit protection.
- How does the high-voltage start-up current source benefit the design?
The high-voltage start-up current source provides a quick and lossless power-on sequence, simplifying the design of the auxiliary supply and VCC capacitor.
- What is the VCC operation range of the NCP1239BD100R2G?
The VCC operation range is up to 35 V.
- Does the NCP1239BD100R2G support auto-recovery from fault conditions?
Yes, it supports auto-recovery from certain fault conditions, such as over-power and over-temperature protection.
- What is the peak sink current capability of the DRV pin?
The peak sink current capability is ±500 mA.
- Is the NCP1239BD100R2G Pb-Free and RoHS compliant?
Yes, it is Pb-Free and RoHS compliant.
- What are the typical applications for the NCP1239BD100R2G?
Typical applications include AC-DC converters for TVs, set-top boxes, and printers, as well as offline adapters for notebooks and netbooks.
- How does the frequency jittering feature work?
The frequency jittering feature helps in reducing electromagnetic interference (EMI) by introducing a small variation in the switching frequency.
