AN2864 Datasheet, PDF (1/29 Pages) STMicroelectronics – VIPER17L demonstration board with wide-range

AN2864
Application note
VIPER17L demonstration board with wide-range
input, 5 V / 1 A output and optimized standby performance
Introduction
In consumer applications like LCD TVs, DVD players, set-top boxes and others, it is
desirable to be able to switch on or switch off the application directly from the remote control.
It is therefore necessary to supply the remote control receiver even when the equipment is
not in use (standby mode). In standby mode only a minimum load (in the range of a few tens
of a mW) is present at the power supply output. Often there are a few mA of load present at
the 5 V or 3.3 V power supply output. Even if no load is applied to the power converter,
some power is still sunk by the mains to keep the converter alive. The load for the mains is
constant (24 hours per day) giving a good contribution to the total consumption of the
equipment.
From this consideration arises the need to reduce the consumption of the power supply as
low as possible when it is light loaded or even when it is not loaded.
Consumer equipment manufacturers often give different criteria for measuring the standby
performance of a power supply, depending on both the characteristics of the equipment and
their own considerations. In order to evaluate the standby power supply performance, a
good starting point is the measurement of power consumption when the unit is not loaded.
The STEVAL-ISA058V1 demonstration board is presented with a power consumption of 30
mW in no load condition.
Figure 1. STEVAL-ISA058V1 demonstration board for the VIPER17L
June 2009
Doc ID 15282 Rev 1
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