Getting started
UM2027
10/37
DocID029048 Rev 1
Figure 6: (a) J7 jumper plugged on board
(doubler mode)
Figure 7: (b) Jumper position left free
(rectifier mode)
2.3
DC bus capacitor discharge for demonstration purpose
With default STEVAL-IHT008V1 1000 µF output capacitors (C1, C5)
and associated 50 kΩ
resistors (R9, R11, R14, R16) used in parallel to balance the voltage across the two series
capacitor, the DC bus discharging time takes a few minutes if no load is connected.
A circuit is included to accelerate this discharging time, especially if several startups need
to be performed inside a short time interval for test or demonstration purposes. This circuit
is made with the Q2 MOSFET and R8 Resistor. Q2 remains on for as long as the SW7
SPDT toggle (refer to the "HV CAPACITOR DISCHARGE" label in
Figure 23: "STEVAL-
IHT008V1 silk-screen (Top side)"
) is switched to the momentary ON position.
The two 1000 µF capacitors are then discharged within two seconds, approximately. The
SW2 switch must at least be kept in the momentary ON position during these two seconds.
The D2 LED (refer to the "HVDC" label in
Figure 23: "STEVAL-IHT008V1 silk-screen (Top
side)"
) remains lit while the HVDC voltage is above 50 V, so the SW2 switch can be
released and a new startup can begin as soon as this LED turns off.
2.4
LED indications
Several LEDs are available to signal useful information:
ICL-STATUS" (LED D18): indicates several things according to its color:
When the board is powered, the LED passes from red, to orange, to green, which
indicates that the microcontroller has finished startup (correct mains connection
and line frequency measurement, power supply available, etc.) and the board is
ready. The green LED then switches off to reduce the board consumption in
standby. From this moment, the DC output capacitor can be charged when the
"HVDC" switch (SW6) is set to the "ON" position.
Green flashing indicates the DC bus capacitors are charging (flashing starts after
setting the "HVDC" button to the ON position and ends when the DC bus
capacitors are fully charged). This flashing mode can last less than 1 second and
may therefore go undetected by the end-user.
Green constant indicates the DC bus is charged to the correct voltage.
Orange flashing indicates the DC bus capacitors are charging but the output DC
voltage rate of increase is too low. This may occur if a power load is connected to