NCP1250 Series

PWM Controller, Current Mode, for Offline Power Supplies

Catalog

PWM Controller, Current Mode, for Offline Power Supplies

Part	Mounting Type	Package / Case	Internal Switch(s)	Duty Cycle	Fault Protection	Operating Temperature [Min]	Operating Temperature [Max]	Frequency - Switching	Voltage - Start Up	Supplier Device Package	Voltage - Supply (Vcc/Vdd) [Max]	Voltage - Supply (Vcc/Vdd) [Min]	Topology	Output Isolation	Board Type	Outputs and Type	Outputs and Type	Supplied Contents	Current - Output	Utilized IC / Part	Main Purpose	Power - Output	Voltage - Output	Voltage - Input [Min]	Voltage - Input [Max]
ON Semiconductor NCP1250ASN65T1G	Surface Mount	SOT-23-6 Thin TSOT-23-6		80 %	Over Power Over Voltage Short Circuit	-40 °C	125 ¯C	65 kHz	18 V	6-TSOP	28 V	8.8 V	Flyback	Isolated
ON Semiconductor NCP1250B40WGEVB															Fully Populated	Isolated	1	Board(s)	3.3 A	NCP1250	AC/DC Primary Side	40 W	12 V	85 VAC	265 VAC

Catalog

PWM Controller, Current Mode, for Offline Power Supplies

Key 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

Description

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.