L6230

Application information

Doc ID 18094 Rev 2

17/24

Figure 15.

Six-step with current control typical application

6.3

Six-step driving method with BEMF zero crossing detection

The BEMF zero crossing information can be used to evaluate the rotor position; in this way

no Hall effect sensors or encoder are needed.

In six-step driving mode one of the three phases is left in high impedance state.

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

zero-crossing.

In shown example (see Figure 16), the OUT1 phase voltage is monitored by the CP+; the

center-tap voltage is obtained as combination of three phase voltages and monitored by the

CP- pin. Only when the OUT1 is in high impedance, the CPOUT will perform a commutation

each time a BEMF zero crossing is detected.

In this configuration one sense resistor is needed, the three OUT pins are connected