The NCP101X series integrates a fixed−frequency current−mode

controller and a 700 V MOSFET. Housed in a PDIP−7 or SOT−223

package, the NCP101X offers everything needed to build a rugged and

low−cost power supply, including soft−start, frequency jittering,

short−circuit protection, skip−cycle, a maximum peak current setpoint

and a Dynamic Self−Supply (no need for an auxiliary winding).

Unlike other monolithic solutions, the NCP101X is quiet by nature:

during nominal load operation, the part switches at one of the available

frequencies (65 − 100 − 130 kHz). When the current setpoint falls

below a given value, e.g. the output power demand diminishes, the IC

automatically enters the so−called skip−cycle mode and provides

excellent efficiency at light loads. Because this occurs at typically 1/4

of the maximum peak value, no acoustic noise takes place. As a result,

standby power is reduced to the minimum without acoustic noise

generation.

Short−circuit detection takes place when the feedback signal fades

away, e.g. in true short−circuit conditions or in broken Optocoupler

cases. External disabling is easily done either simply by pulling the

feedback pin down or latching it to ground through an inexpensive

SCR for complete latched−off. Finally soft−start and frequency

jittering further ease the designer task to quickly develop low−cost and

robust offline power supplies.

For improved standby performance, the connection of an auxiliary

winding stops the DSS operation and helps to consume less than

100 mW at high line. In this mode, a built−in latched overvoltage

protection prevents from lethal voltage runaways in case the

Optocoupler would brake. These devices are available in economical

8−pin dual−in−line and 4−pin SOT−223 packages.

Features

• Built−in 700 V MOSFET with Typical RDSon of 11 

and 22 

• Large Creepage Distance Between High−Voltage Pins

• Current−Mode Fixed Frequency Operation:

65 kHz – 100 kHz − 130 kHz

• Skip−Cycle Operation at Low Peak Currents Only:

No Acoustic Noise!

• Dynamic Self−Supply, No Need for an Auxiliary

Winding

• Internal 1.0 ms Soft−Start

• Latched Overvoltage Protection with Auxiliary

Winding Operation

• Frequency Jittering for Better EMI Signature

• Auto−Recovery Internal Output Short−Circuit

Protection

• Below 100 mW Standby Power if Auxiliary Winding

is Used

• Internal Temperature Shutdown

• Direct Optocoupler Connection

• SPICE Models Available for TRANsient Analysis

• These are Pb−Free and Halide−Free Devices

Typical Applications

• Low Power AC/DC Adapters for Chargers

• Auxiliary Power Supplies (USB, Appliances,TVs, etc.)