Product Overview

Product Overview
NCP1308: Controller, Free Running Quasi-Resonant Current Mode
For complete documentation, see the data sheet
Product Description
The NCP1308 combines a true current mode modulator and a demagnetization detector to ensure full borderline/Critical Conduction
Mode in any load/line conditions and minimum drain voltage switching (Quasi-Resonant operation). Due to its inherent skip cycle
capability, the controller enters burst mode as soon as the power demand falls below a predetermined level. As this happens at low
peak current, no audible noise can be heard. An internal 10us timer prevents the free-run frequency to exceed a high frequency
(therefore below the 150kHz CISPR-22 EMI starting limit), while the skip adjustment capability lets the user select the frequency at
which the burst foldback takes place. The Dynamic Self-Supply (DSS) drastically simplifies the transformer design in avoiding the
use of an auxiliary winding to supply the NCP1308. This feature is particularly useful in applications where the output voltage varies
during operation (e.g. battery chargers). Thanks to its high-voltage technology, the IC is directly connected to the high-voltage DC
rail. As a result, the short-circuit trip point is not dependent upon any VCC auxiliary level. The transformer core reset detection is
done through an auxiliary winding which, brought via a dedicated pin. If an OVP has been detected on the Vcc pin, the IC
permanently latches-off. Finally, the continuous feedback signal monitoring implemented with an over-current fault protection
circuitry (OCP) makes the final design rugged and reliable.
Features
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FreeRunning Borderline/Critical Mode QuasiResonant Operation
CurrentMode with Adjustable Skip Cycle Capability
Dynamic SelfSupply Type of VCC
AutoRecovery Overcurrent Protection
Improved UVLO for VCC below 10 VDevice Package Shipping
Latching Overvoltage Protection on VCC
500 mA Peak Current Source/Sink Capability
Internal 1.0 ms SoftStart
Internal 10 us Minimum TOFF
Adjustable Skip Level
For more features, see the data sheet
Applications
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ACDC Adapters for Notebooks, etc.
Offline Battery Chargers
Consumer Electronics (DVD Players, SetTop Boxes, TVs, etc.)
Auxiliary Power Supplies (USB, Appliances, TVs, etc.)
Part Electrical Specifications
Product
Compliance
Status
Topolog
y
Control
Mode
fsw Typ
(kHz)
StandUVLO
by Mode (V)
Short
Circuit
Protecti
on
Latch
Soft
Start
VCC Max Drive
(V)
Cap.
(mA)
Packag
e Type
NCP1308DR2G
Pb-free
Active
Flyback
Current
Mode
Variable
Yes
Yes
Yes
Yes
16
SOIC-8
Halide free
Yes
500 /
500
Application Diagram
For more information please contact your local sales support at www.onsemi.com
Created on: 6/30/2016