Secondary Side SMPS OFF
Mode Controller for Low
The NCP4355 is a secondary side SMPS controller designed for use
in applications which require extremely low no load power
consumption. The device is capable of detecting “no load” conditions
and entering the power supply into a low consumption OFF mode.
During OFF mode, the primary side controller is turned off and energy
is provided by the output capacitors thus eliminating the power
consumption required to maintain regulation. During OFF mode, the
output voltage relaxes and is allowed to decrease to an adjustable
level. Once more energy is required, the NCP4355 automatically
restarts the primary side controller by ONOFF current that flows
through ONOFF optocoupler. The NCP4355 controls the primary
controller with an “Active ON” signal, meaning that it only drives
optocoupler current during ON mode to minimize consumption during
During normal power supply operation, the NCP4355 provides
integrated voltage feedback regulation, replacing the need for a shunt
regulator. The A and C versions include a current regulation loop in
addition to voltage regulation.
The NCP4355 includes a LED driver pin (except C version)
implemented with an open drain MOSFET driven by a 1 kHz square
wave with a 12.5% duty cycle for indication purpose.
The NCP4355 is available in SOIC−8 package.
• Operating Input Voltage Range: 3.5 V to 36.0 V
• Supply Current < 100 mA
• ±0.5% Reference Voltage Accuracy (TJ = 25°C)
• Constant Voltage and Constant Current (A and C versions) Control
• Indication LED PWM Modulated Driver (except NCP4355C)
• These Devices are Pb−Free, Halogen Free/BFR Free and are RoHS
• Offline Adapters for Notebooks, Game Stations and Printers
• High Power AC−DC Converters for TVs, Set−Top Boxes, Monitors etc.
XXXXX = Specific Device Code
A = Assembly Location
L = Wafer Lot
Y = Year
W = Work Week
G = Pb−Free Package
See detailed ordering, marking and shipping information in the
package dimensions section on page 16 of this data sheet.
© Semiconductor Components Industries, LLC, 2013
August, 2013 − Rev. 1
Publication Order Number: