STEVAL-IHM021V1 STMicroelectronics, STEVAL-IHM021V1 Datasheet - Page 17

BOARD EVAL L6390/STD5NK52ZD

STEVAL-IHM021V1

Manufacturer Part Number
STEVAL-IHM021V1
Description
BOARD EVAL L6390/STD5NK52ZD
Manufacturer
STMicroelectronics
Type
Motor / Motion Controllers & Driversr

Specifications of STEVAL-IHM021V1

Main Purpose
Power Management, Motor Control
Embedded
Yes, MCU, 32-Bit
Utilized Ic / Part
L6390, STD5NK52ZD-1
Primary Attributes
3-Ph PMSM, 100 W 3-Phase Inverter, 110 ~ 230VAC
Secondary Attributes
Field-Oriented Control (FOC) of Sinusoidal-Shaped Back-EMF
Input Voltage
110 V to 230 V
Product
Power Management Modules
Lead Free Status / RoHS Status
Lead free / RoHS Compliant
For Use With/related Products
L6390, STD5NK52ZD-1
Other names
497-8404
L6390
9
9.1
Bootstrap driver
A bootstrap circuitry is needed to supply the high voltage section. This function is normally
accomplished by a high voltage fast recovery diode
integrated structure replaces the external diode. It is realized by a high voltage DMOS,
driven synchronously with the low side driver (LVG), with diode in series, as shown in
8.b. An internal charge pump
C
To choose the proper C
capacitor. This capacitor C
Equation 1
The ratio between the capacitors C
It has to be:
Equation 2
e.g.: if Q
300 mV.
If HVG has to be supplied for a long time, the C
the leakage and quiescent losses.
e.g.: HVG steady state consumption is lower than 200 μA, so if HVG T
to supply 1 μC to C
The internal bootstrap driver gives a great advantage: the external fast recovery diode can
be avoided (it usually has great leakage current).
This structure can work only if V
LVG is on. The charging time (T
fulfilled and it has to be long enough to charge the capacitor.
The bootstrap driver introduces a voltage drop due to the DMOS R
120 Ω). At low frequency this drop can be neglected. Anyway increasing the frequency it
must be taken in to account.
The following equation is useful to compute the drop on the bootstrap DMOS:
BOOT
gate
selection and charging
is 30 nC and V
EXT
. This charge on a 1 μF capacitor means a voltage drop of 1V.
BOOT
EXT
gate
value the external MOS can be seen as an equivalent
(Figure
Doc ID 14493 Rev 5
is related to the MOS total gate charge:
is 10 V, C
charge
OUT
EXT
is close to GND (or lower) and in the meanwhile the
C
) of the C
C
8.b) provides the DMOS driving voltage.
and C
BOOT
EXT
EXT
is 3 nF. With C
BOOT
>>> C
=
BOOT
BOOT
Q
------------- -
V
gate
gate
is proportional to the cyclical voltage loss.
EXT
is the time in which both conditions are
(Figure
selection has to take into account also
BOOT
8.a). In the L6390 a patented
= 100 nF the drop would be
DSon
ON
(typical value:
is 5 ms, C
Bootstrap driver
BOOT
Figure
17/22
has

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