UM0522
Board architecture
15/39
Figure 5.
Power supply architecture
7.2 Power
stage
The power stage is based on six power MOSFETs in full 3-phase bridge configuration. In
the board there are six STD5NK52ZD-1s in an IPAK package. Each device contains the
freewheeling Zener diode. Three L6386 have been used to drive the Power MOSFETs gates
and for hardware current protection. For each Power MOSFET in the 3-phase bridge the
network shown in
(default configuration) has been used as the starting
configuration.
Figure 6.
Gate driving network
In this default configuration the gate of the Power MOSFET is turned on by means of R1 and
D22 while the turnoff is performed very fast by means of the Q1 transistor. It is also possible
to use the alternate configuration of the network (See
). To set this configuration
transistor Q1, resistor R5 and C13 must be removed from each network (6). The direction of
the diode D22 must be inverted and a resistor R20 must be mounted. In this alternate
configuration the gate of the Power MOSFET is turned on by means of R1 and R20 while
the turnoff is performed by means of R1 and D22.
Rectifier
Rectifier
Vac
Vdc = Vac
2
Vbus
Buck converter
VIPer 12
+15V
+5V
Linear
regulator
L7805
Vdrivers
15V auxiliary
supply
CON2
D22
R21
22R
R1
100R
R5
220R
C13
100pF
Q1
R20
D22
R21
22R
R1
100R
Default configuration
Alternate configuration
Turn on
Turn off
Turn on
Turn off
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