NCP1248: Fixed Frequency Current Mode Controller for Flyback Converters
The NCP1248 is a new fixed-frequency current-mode controller featuring the Dynamic Self-Supply. This function greatly simplifies the design of the auxiliary supply and the VCC capacitor by activating the internal startup current source to supply the controller during start-up, transients, latch, stand-by etc. This device contains a special HV detector which detect the application unplug from the AC input line and triggers the X2 discharge current. This HV structure allows the brown-out detection as well. It features a timer-based fault detection that ensures the detection of overload and an adjustable compensation to help keep the maximum power independent of the input voltage. Due to frequency foldback, the controller exhibits excellent efficiency in light load condition while still achieving very low standby power consumption. Internal frequency jittering, ramp compensation, and a versatile latch input make this controller an excellent candidate for the robust power supply designs. A dedicated Off mode allows to reach the extremely low no load input power consumption via “sleeping” whole device and thus minimize the power consumption of the control circuitry.
This product is IEC60950 compliant. Please see the test report and certification in the Conformance report section below.
Features- Frequency foldback and skip mode
- Timer-based overload protection with latched (A version) or auto-recovery (B version) operation
- High-voltage startup with dynamic self supply
- Integrated brown-out detection
- Frequency Modulation
- Adjustable overpower protection
- Latch off input
| Benefits- Optimized efficiency across the entire load range
- Protection against overcurrent and short circuit
- Simplifies the design of the auxiliary supply
- Protects against any drops in line voltage
- Softened EMI signature
- Automatically adjusts the current limit depending on the line input voltage (high line or low line)
- Protection against faults
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Applications- AC-DC Adapters
- LCD TV power supplies
| End Products |
Data Sheets (1)
Package Drawings (1)
Order Information
| Product | Status | Compliance | Package | MSL* | Container | Budgetary Price/Unit |
|---|
| NCP1248AD065R2G | Active | Pb-free
Halide free | SOIC-7 | 751U | 1 | Tape and Reel | 2500 | $0.5 |
| NCP1248AD100R2G | Active | Pb-free
Halide free | SOIC-7 | 751U | 1 | Tape and Reel | 2500 | $0.5 |
Specifications
| Product | Topology | Control Mode | fsw Typ (kHz) | Stand-by Mode | UVLO (V) | Short Circuit Protection | Latch | Soft Start | VCC Max (V) | Drive Cap. (mA) |
|---|
| NCP1248AD065R2G | Step-Up/Step-Down | Current Mode | 65 | Yes | 8.9 | Yes | Yes | Yes | 28 | 500 / 800 |
| NCP1248AD100R2G | Step-Up/Step-Down | Current Mode | 100 | Yes | 8.9 | Yes | Yes | Yes | 28 | 500 / 800 |
