UM1943

Circuit description

DocID028304 Rev 1

21/28

4.3

Analog section

– Hall/Encoder motor speed sensor

The X-NUCLEO-IHM07M1 expansion board implements the Hall/Encoder sensor detecting

circuit for speed measurement. The motor sensor pin, through the J3 connector and an

analog circuit, are connected to the STM32 Nucleo board in order to detect the motor spin;

a +5 V and GND are also provided for power supply of the sensors. For sensors that

require external pull-up, jumper JP3 is available (see figure below). For this setting please,

refer to Table 1: "Jumper settings".

Figure 16: X-NUCLEO-IHM07M1

– hall/encoder sensor circuit

4.4

Analog section

– BEMF detection circuit

The X-NUCLEO-IHM07M1 expansion board provides two hardware solutions for motor

position measuring, one based on sensors (refer to Section 4.3: "Analog section

–

Hall/Encoder motor speed sensor") and the other based on sensorless detection. In six-

step driving mode one of the three phases is left in high impedance state and comparing

the voltage of this phase with the center-tap voltage, we can detect the BEMF zero-

crossing. This signal is acquired with an analog circuit embedded on the board, as shown

in the diagram below.

Figure 17: X-NUCLEO-IHM07M1

– BEMF detection circuit

4.5

Analog section

– Bus voltage and temperature sensing

circuit

The X-NUCLEO-IHM07M1 expansion board provides the hardware for bus voltage sensing

and temperature measurement. This signal is acquired respectively with a resistor divider

HALL/ENCODER SENSOR

5V

GND

A+/H1

B+/H2

Z+/H3

3V3

3V3

5V

A+/H1

B+/H2

Z+/H3

R30

1k8

JP3

JUMPER

C20

R32

1k8

R34

4K7 N.M.

R31

1k8

R33

4K7 N.M.

R29

10k

J3

Stripline m. 1x5

1

2

3

4

5

C22

R28

10k

R27

10k

D4

D3

D2

C19

100n

R35

4K7 N.M.

J4

RING

1

C21

GSPG15092015DI0645

BEMF DETECTION - SIX STEP

OUT1

OUT2

OUT3

GPIO_BEMF

GPIO_BEMF

GPIO_BEMF

BEMF1

BEMF3

3V3

3V3

3V3

3V3

GPIO_BEMF

BEMF1

BEMF2

GPIO_BEMF

GPIO_BEMF

BEMF3

R39

10k

R36

2.2k

D10

BAT30KFILM

D6

BAT30KFILM

R41

10k

D9

BAT30KFILM

D5

BAT30KFILM

D8

BAT30KFILM

R38

2.2k

C23

0.1uF/6.3V

R40

10k

D7

BAT30KFILM

R37

2.2k

GSPG15092015DI0650