NCP1250: PWM Controller, Current Mode, for Offline Power Supplies
The NCP1250 is a highly integrated PWM controller capable of delivering a rugged and high performance offline power supply in a tiny TSOP-6 package. With a supply range up to 28 V, the controller hosts a jittered 65 kHz or 100 kHz switching circuitry operated in peak current mode control. When the power on the secondary side starts to decrease, the controller automatically folds back its switching frequency down to a minimum level of 26 kHz. As the power further goes down, the part enters skip cycle while limiting the peak current. 40W AdapterOver Power Protection (OPP) is a difficult exercise especially when no-load standby requirements drive the converter specifications. The ON proprietary integrated OPP lets you harness the maximum delivered power without affecting your standby performance simply via two external resistors. An Over Voltage Protection input is also combined on the same pin and protects the whole circuitry in case of optocoupler failure or adverse open loop operation. Finally, a timer-based short-circuit protection offers the best protection scheme, letting you precisely select the protection trip point irrespective of a loose coupling between the auxiliary and the power windings.
Features- Non-dissipative internal and adjustable Over Power Protection (OPP) circuits
- Frequency Foldback down to 26 kHz and Skip-Cycle in light load conditions
- Internal Ramp Compensation
- Frequency jittering from full load to skip-cycle
- Latch input for OVP and OTP implementations
- See NCP1251 for integrated Over Voltage Protection (OVP) monitoring on the Vcc pin
| Benefits- Limits maximum delivered power without affecting standby performance
- High efficiency in light load conditions
- Reduces the number of external components
- Improved EMI performance
- Simple implementation of required protection functions
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Applications- Offline Adapters
- AC-DC converters
| End Products- Set-top Boxes
- Printers
- Notebooks and Netbooks
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Design & Development Tools (2)
Package Drawings (2)
Document Title | Document ID/Size | Revision |
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8 LEAD PDIP | 626-05 (35.0kB) | P |
TSOP-6 | 318G-02 (64.1kB) | V |
Application Notes (7)
Evaluation Board Documents (4)
Simulation Models (3)
Data Sheets (1)
Evaluation/Development Tool Information
Product | Status | Compliance | Short Description |
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NCP1250B40WGEVB | Active | Pb-free | 40 W Notebook Adapter Demonstration Evaluation Board |
Order Information
Product | Status | Compliance | Package | MSL* | Container | Budgetary Price/Unit |
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NCP1250ASN100T1G | Active | Pb-free
Halide free | TSOP-6 | 318G-02 | 1 | Tape and Reel | 3000 | $0.14 |
NCP1250ASN65T1G | Active | Pb-free
Halide free | TSOP-6 | 318G-02 | 1 | Tape and Reel | 3000 | $0.14 |
NCP1250BP65G | Active | Pb-free
Halide free | PDIP-8 | 626-05 | NA | Tube | 50 | $0.2267 |
NCP1250BSN100T1G | Active | Pb-free
Halide free | TSOP-6 | 318G-02 | 1 | Tape and Reel | 3000 | $0.14 |
NCP1250BSN65T1G | Active | Pb-free
Halide free | TSOP-6 | 318G-02 | 1 | Tape and Reel | 3000 | $0.14 |
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) |
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NCP1250ASN100T1G | Flyback | Current Mode | 100 | Yes | 8.8 | Yes | Yes | Yes | 28 | 300 / 500 |
NCP1250ASN65T1G | Flyback | Current Mode | 65 | Yes | 8.8 | Yes | Yes | Yes | 28 | 300 / 500 |
NCP1250BP65G | Flyback | Current Mode | 65 | Yes | 8.8 | Yes | Yes | Yes | 28 | 300 / 500 |
NCP1250BSN100T1G | Flyback | Current Mode | 100 | Yes | 8.8 | Yes | Yes | Yes | 28 | 300 / 500 |
NCP1250BSN65T1G | Flyback | Current Mode | 65 | Yes | 8.8 | Yes | Yes | Yes | 28 | 300 / 500 |