Board description
UM1036
16/48
Doc ID 18293 Rev 1
3.3 Circuit
description
3.3.1 Power
supply
The power supply for the STEVAL-IHM028V1 demonstration board is implemented as
a wide range converter. The range of the input voltage is from 90 VAC or 125 VDC up to 285
VAC or 400 VDC. This range allows the demonstration board to be used in direct connection
with various single phases as well as the PFC input stage.
If the input AC voltage does not surpass 145 VAC, it is possible to apply the input voltage
doubler, this is done by shorting the W15 jumper. This configuration almost doubles the
input AC voltage to a standard level and allows to evaluate the motor control application with
a low level of input AC voltage.
The auxiliary power supply for all active components on the demonstration board is
implemented as a buck converter based on U2 VIPer26L which works with a fixed frequency
of 60 kHz. The output voltage of the converter is +15 VDC. Voltage is fed into the intelligent
power module (IPM) as supply voltage, as well as into linear regulators LF33ABDT and
L78M05AB. Linear regulators p3.3 VDC and +5 VDC for supplying operational
amplifiers and further related parts placed on the demonstration board. The selection of
supply voltage for hardware peripherals placed on the board is done with jumper W1. In the
“A” position the supply voltage selected is +3.3 V and in the “B” position it is +5 V. Thanks to
jumper W3, it is possible to supply the connected MCU driving board with related supply
voltage. Maximal consumptive current of the MCU unit must not surpass 50 mA. Please
refer to the VIPer26LD datasheet for more information.
Information regarding the value of the supply bus voltage on the main filtering capacitors is
sensed with the voltage divider built around R2, R5, and R8 and is fed into the dedicated
control unit through the J2 connector. The proper voltage partitioning for applied resistor
values is 0.0075.
The presence of +15 VDC on the board is indicated with the D5 green LED “Power ON”.
Figure 9
describes the power supply section with a simplified block diagram.
Figure 9.
Power supply block diagram
,INEARREGULATOR
,&
"RIDGE
RECTIFIER
"UCKCONVERTER
6)0ER,$
,INEARREGULATOR
,-
6$#
6$#
).054
$#"53
6$#
"536$#
-).
6!#
6$#
-!8
6!#
6$#
7
6OLTAGE
DOUBLER
-!86$#
!-
