UM0432
Board architecture
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6.1 Power
supply
The power supply has been designed to address a wide range of DC bus voltages from 5 to
48 V. Three power supply configurations have been implemented.
●
Low voltage: 5–6.5 volts based on the L5970 boost converter.
●
Medium voltage: a 6.5–9-volt direct connection to the bus.
●
High voltage: 9–48 volts based on an L4976 buck converter (for V
BUS
> 28 V, the power
MOSFET must be replaced with the STD20NF06LT4 or STS7NF60L).
Figure 5.
Power supply architecture
To supply the 5 volts to the micro, you can use either the
Vref signal of the L4976D regulator
if it is used (high voltage setting in
Table 4
), or the LK112SM50TR. The first setting can be
configured by putting J8 between pins 2-3 and the second configuration by putting J8
between pins 1-2.
With the L4976D’s Vref signal, it is possible to provide the microcontroller with up to 20 mA.
With the LK112SM50TR it is possible to provide up to 200 mA.
6.2 Power
stage
The power stage is based on six power MOSFETs in full 3-phase bridge configuration. The
board has three STS8DNH3LLs in SO-8 package, each containing two devices. The
maximum driving current is 8 A and the suggested maximum driving voltage is 24 V.
Different power MOSFET devices can be used, replacing U15, U17 and U18 with other
devices. Compatible devices are power MOSFETs in SO-8 package containing single or
Table 4.
Power supply jumper settings
Configuration
V
BUS
range
V Driver
Jumper configuration
Low voltage
5–6.5 V
7 V
J23 between 1-2
J24 between 2-3
Medium voltage
6.5–9 V
V
BUS
J23 pin2 – J22
J24 pin 2 – J27
High voltage
9–48 V
8 V
J23 between 2-3
J24 between 1-2
V (Driver)
V (Micro)
L4976D
J23
2
1
1
3
L5970D
J24
2
3
1
1
LK112SM50
VBus
J22
J27
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