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E-L6219R View Datasheet(PDF) - STMicroelectronics

Part Name
Description
Manufacturer
E-L6219R
ST-Microelectronics
STMicroelectronics ST-Microelectronics
E-L6219R Datasheet PDF : 11 Pages
1 2 3 4 5 6 7 8 9 10
L6219R
3 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
3.1 Input Logic (I0 and I1)
The current level in the motor winding is selected with these inputs. (See fig. 5)
If any of the logic inputs is left open, the circuit will treat it has a high level input.
Table 6.
I0
I1
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
Current Level
3.2 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
3.3 Current Sensor
This part contains a current sensing resistor (RS), a low pass filter (RC, CC) and three comparators.Only one
comparator is active at a time. It is activated by the input logic according to the current level chosen with signals
Io and I1.The motor current flows through the sensing resistor RS.When the current has increased so that the
voltage across RS 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:
Imax
=
--V----r---e---f-
10Rs
See figures 4, 5 and 6 for maximum allowable output current and reference voltage versus Vs supply.
3.4 Single-pulse Generator
The pulse generator is a monostable triggered on the positive going edge of the comparator output.The
monostable output is high during the pulse time, toff , which is determined by the time components Rt and Ct.
toff = 1.1 · RtCt
The single pulse switches off the power feed to the motor winding, causing the winding current to decrease dur-
ing toff.If a new trigger signal should occur during toff, it is ignored.
3.5 Output Stage
The output stage contains four Darlington transistors (source drivers) four saturated transistors (sink drivers)
and eight diodes, connected in two H bridge.
5/11
 

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