
4 Circuit description
The STSPIN230 integrates a protected triple half-bridge with low RDS(on) for evaluating a
solution for a three-phase BLDC motor in very low consumption mode.
The device is protected against overload and short-circuits: short to ground, short to motor
supply voltage, short between the outputs. If one of the failure events occurs, the fault
signal is set and the fault LED D5 is lit (red).
The STSPIN230 is compatible with single shunt current sense measurement. The current
feedback signal conditioning is performed by hardware available on the board and sent to
the STM32 Nucleo board through the CN7 ST morpho connector (pin 28).
Motor speed regulation can be performed by hardware, by acting on trimmer R12. In this
way, you can change the reference used by STM32 firmware for speed regulation.
The X-NUCLEO-IHM11M1 expansion board provides two hardware solutions for motor
position feedback: one based on sensors and the other one based on sensorless detection.
4.1 Hall/encoder motor speed sensor
The X-NUCLEO-IHM11M1 expansion board implements the Hall/encoder sensor detection
circuit for motor speed feedback. The motor sensor feedback is connected through the J3
connector and an analog circuit to the STM32 Nucleo board in order to detect the motor
rotation.
For sensors requiring external pull-up, three 10 kΩ resistors are already mounted and
connected to the VDD voltage (if these are not necessary, you can remove them).
The J4 jumper (closed by default) protects the Hall’s input lines connecting them to VDD
voltage through a small-signal Schottky diode.
4.2 Sensorless detection
In six-step driving mode, one of the three phases is left in high impedance state: comparing
this phase voltage with the center-tap voltage, we can detect the BEMF zero-crossing.
This signal is acquired through an analog circuit embedded on the expansion board and
sent to the STM32 Nucleo board through the ST morpho connectors.
For each different STM32 Nucleo development board, the BEFM3 driver input can be
selected through a dedicated resistor, as indicated in the table below.
Table 3: BEFM3 input selection
NUCLEO-F030R8
NUCLEO-L053R8
4.3 Bus voltage circuit
The X-NUCLEO-IHM11M1 expansion board provides the hardware bus voltage sensing.
This signal is acquired with a resistor divider from the motor supply voltage (VBUS) and
sent to the analog to digital converter (connector CN7 pin 30).