Overview
The NCP1236AD100R2G is a fixed-frequency current-mode controller designed by onsemi. This device is part of the NCP1236 family and is pin-to-pin compatible with the previous NCP12xx series. It features Dynamic Self-Supply (DSS), which simplifies the design of the auxiliary supply and the VCC capacitor. The controller is optimized for use in flyback converters and offers enhanced safety and efficiency features, including frequency foldback, overload protection, and brown-out detection.
Key Specifications
| Parameter | Unit | Min | Typ | Max |
|---|---|---|---|---|
| Oscillator Frequency | kHz | 65 / 100 | 65 / 100 | 65 / 100 |
| VCC Operation Range | V | 4.0 | - | 28 |
| Overvoltage Threshold (VCC) | V | 25 | 26.5 | 28 |
| Peak Source / Sink Current Drive Capability | mA | - | - | 500 |
| Soft-Start Duration | ms | - | 4.0 | - |
| Internal Thermal Shutdown | - | - | - | - |
| Operating Temperature Range | °C | -40 | - | 125 |
| Package Type | - | - | SOIC-7 | - |
Key Features
- Fixed-Frequency Current-Mode Operation with Built-In Ramp Compensation: Ensures maximum safety and prevents sub-harmonic oscillations.
- Frequency Foldback then Skip Mode for Light Load Conditions: Maximizes efficiency in light load and standby conditions by reducing switching frequency down to 27 kHz.
- Timer-Based Overload Protection with Latched or Auto-Recovery Operation: Provides safety against overloads with options for latched or auto-recovery modes.
- High-Voltage Current Source with Brown-Out Detection and Dynamic Self-Supply: Simplifies the design of the VCC capacitor and ensures clean start-up and operation during transients.
- Adjustable Overpower Compensation: Allows adjustment of the current sense voltage offset proportional to the input voltage.
- Frequency Modulation for Softened EMI Signature: Helps in passing EMI limits by spreading out the energy content of frequency peaks.
- Latch-Off Input for Severe Fault Conditions: Allows direct connection of an NTC for overtemperature protection.
- Soft-Start and Internal Thermal Shutdown: Minimizes stress on power components during start-up and protects against self-overheating.
Applications
- AC-DC Adapters for Notebooks, LCD, and Printers
- Offline Battery Chargers
- Consumer Electronic Power Supplies
- Auxiliary/Housekeeping Power Supplies
Q & A
- What is the primary function of the NCP1236AD100R2G?
The NCP1236AD100R2G is a fixed-frequency current-mode controller designed for use in flyback converters.
- What is the Dynamic Self-Supply (DSS) feature?
The DSS feature simplifies the design of the auxiliary supply and the VCC capacitor by activating the internal startup current source to supply the controller during transients.
- What are the available oscillator frequencies for the NCP1236AD100R2G?
The oscillator frequencies available are 65 kHz and 100 kHz.
- How does the frequency foldback feature work?
The frequency foldback feature reduces the switching frequency down to 27 kHz in light load conditions to maximize efficiency.
- What types of overload protection does the NCP1236AD100R2G offer?
The controller offers timer-based overload protection with options for latched or auto-recovery operation.
- How does the brown-out detection work?
The brown-out detection features a high-voltage sensing circuitry that can turn the controller off if the input voltage is too low, working with either DC or rectified AC input voltage.
- What is the purpose of the adjustable overpower compensation?
The adjustable overpower compensation allows the adjustment of the current sense voltage offset proportional to the input voltage.
- How does the soft-start feature work?
The soft-start feature gradually increases the peak current over 4.0 ms to minimize stress on power components during start-up.
- What is the internal thermal shutdown feature?
The internal thermal shutdown feature protects the controller against self-overheating by shutting down all circuitries if the die temperature is too high.
- Is the NCP1236AD100R2G RoHS compliant?
Yes, the NCP1236AD100R2G is Pb-free, halogen-free/BFR-free, and RoHS compliant.
