L6219

Functional description

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Functional description

The circuit is intended to drive both windings of a bipolar stepper motor.

The peak current control is generated through switch mode regulation.There is a choice of

three different current levels with the two logic inputs I01 - I11 for winding 1 and I02 - I12 for

winding 2.

The current can also be switched off completely.

2.1

The current level in the motor winding is selected with these inputs. (See Figure 4). If any of

the logic inputs is left open, the circuit will treat it has a high level input.

2.2

Phase

This input determines the direction of current flow in the windings, depending on the motor

connections. The signal is fed through a Schmidt-trigger for noise immunity, and through a

time delay in order to guarantee that no short-circuit occurs in the output stage during

phase-shift.High level on the PHASE input causes the motor current flow from Out A

through the winding to Out B.

2.3

Current sensor

comparators. Only one comparator is active at a time. It is activated by the input logic

becomes higher than the reference voltage on the other comparator input, the comparator

goes high, which triggers the pulse generator.

The max peak current Imax can be defined by:

Table 6.

Current levels

I0

I1

Current level

H

H

No current

L

H

Low current 1/3 IO max

H

L

Medium current 2/3 IO max

L

L

Maximum current IO max

I

max

V

ref

10R

s

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