STEVAL-ISA192V1 Datasheet, PDF (1/5 Pages) STMicroelectronics – RoHS compliant

STEVAL-ISA192V1
7 W dual output flyback converter with standby managed by
capacitive touch using VIPer0P and STM32L
Data brief
Features
 Smart standby architecture using the zero
power mode (ZPM) for capacitive touch
sensing in consumer electronics applications
 Enhanced system reliability thanks to
VIPer0P 800 V avalanche rugged
technology and its embedded protection
 Minimized system input power consumption:
less than 30 mW at 230 VAC in ZPM
 IEC55022 Class B conducted EMI
compliant, even with reduced EMI filter,
thanks to the frequency jittering feature
 IEC61000-4-2 (ESD), IEC61000-4-4 (EFT)
and IEC61000-4-5 (Surge) compliant
 RoHS compliant
Description
This offline converter key feature is the zero
power mode (ZPM), an idle state during which
the device is totally shut down. The IC enters
ZPM by pulling the OFF pin to SGND for more
than 10 ms and exits ZPM (resuming normal
switching) by pulling the ON pin to SGND for
more than 20 μs. This function can be tested via
the tactile switches connected to the ON and
OFF pins.
In ZPM the mains power consumption at 230 VAC
can be below 5 mW; the STEVAL-ISA192V1
evaluation board consumption is 30 mW due to
the MCU polling strategy implemented at
firmware level.
The board has a dual output (i.e., - 5 V and + 7 V
based on flyback topology). The negative output
is obtained by just connecting EAGND to the
negative rail and a voltage divider among FB,
EAGND and SGND. The positive output derives
from the turn ratio of the transformer secondary
windings.
To achieve extremely low input power
consumption, the IC is biased through a diode
coming from the + 7 V, which maintains the VCC
voltage high enough (> 4.5 V) to prevent the
internal HV current source activation.
The STEVAL-ISA192V1 is equipped with the
STM32L0 microcontroller which detects tactile
push buttons and capacitive touch interface. The
STM32L0 core manages VIPer0P to achieve
minimum power consumption in ZPM, while
supplying the microcontroller and user interface
(capacitive touch and push button) and still
maintaining the overall efficiency quite high in
standard operation mode.
February 2017
DocID030285 Rev 1
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