Description
This document describes a 5 V-2 A application
with 3.3 A peak current capability for 1.9 sec,
using VIPer28H, a new off-line high voltage
converter from STMicroelectronics.
In some applications an SMPS, normally
supposed to deliver a certain amount of power,
from time to time undergoes load peaks that can
be even two or more times as much, but only for
a time interval which is short if compared to the
thermal time constants of the power components.
Typical examples of such loads are printers and
audio systems.
In these cases, it is more cost-effective to
thermally design the system for the maximum
continuous power and not for the peak power
demand, which will be sustained only for a limited
time window.
Such a design is possible thanks to the EPT
function of VIPER28H, which allows the designer
to fix the maximum time window during which the
converter is able to manage the peak power still
maintaining output voltage regulation. If the
overload lasts more than this time window, the
converter is automatically shut down in autorestart mode, in order to avoid the damaging of
the power components.

Features
• Input Voltage range: 90 VRMS to 265 VRMS
• Output Voltage: 5 V
• Max Output Current: IOUTmax 2 A
• Peak Output Current: IOUTpk 3 A
• Precision of output regulation: ΔVOUT_LF ±5%
• High Frequency output Voltage ripple:
ΔVOUT_HF 50 mV
• Max ambient operating temperature: TA 60
ºC
• 800 V avalanche rugged power section
• PWM operation , at 115 kHz with frequency
jittering for lower EMI
• Limiting current with adjustable set point
• On-board soft-start
• Safe auto-restart after a fault condition, low
stand-by power (< 50 mW at 265 Vac)
• Adjustable and accurate over voltage
protection, thermal shutdown with
hysteresis, delayed overload protection
• RoHS compliant