AN4243

Application information

Doc ID 024199 Rev 1

23/29

3.2

Six-step driving method with current control

The input sequence is generated by the external controller and the L6230 comparator is

used to obtain the information for the peak current control. In this configuration, only one

Figure 20).

The non-inverting input comparator CP+ monitors the voltage drop across the external

sense resistor connected between the source of the three lower power MOS transistors and

ground.

proportionally. When the voltage drop across, the sense resistor becomes greater than the

reference voltage applied to inverting input CP- the comparator open-drain output is

switched on pulling down the CPOUT pin.

This signal could be managed by controller to generate the proper input sequence for six-

step driving method with current control and select what current decay method to

implement.

When the sense voltage decreases below the CP- voltage, the open-drain is switched off

The reference voltage at pin CP- is set according to the sense resistor value and the desired

regulated current:

Equation 15

A very simple way to obtain a variable voltage is to low-pass filter a PWM output of a

controller (refer to Section 2.8).

Figure 20.

Six-step with current control typical application

V

CP-

R

SENSE

I

TARGET

×

≅

EN3

CP+

CP-

GND

CPOUT

POWER

GROUND

SIGNAL

GROUND

PWM

from controller

+

-

VCP

VBOOT

DIAG/EN

ENABLE

IN3

EN2

IN2

EN1

IN1

EN3

Current control

signal

IN3

EN2

IN2

EN1

IN1

THREE-PHASE

MOTOR

M

AM16582v1