SYSTEM DESCRIPTION
The L6515 is intended to be used as a microprocessorcontrolledpositioningsystem.
For the motor driver stage only digital operating 
bridgesareneededl ikeL293E,L298,L6203,L6202.
The system operates in two modes to achieve 
high-speed,high-accurancy positioning.
Speed commands for the system originate in the 
microprocessor. It is continuouslyupdated on the 
motor position by means of pulses from the controller chip, which in turn gets its information from 
the encoder. From this basic input, the microprocessor computes a 6-bit control word that sets the 
systemspeed anddirectiondependenton the distance to travel.
When the motor is stopped and the microprocessor orders it to a new position, the system oper-
ates initially in an open-loop configuration as 
there is no feedback from the tachometer generator.Therefore maximumcurrentis fed to themotor. As maximum speed is reached, the tachometer chip output backs off the processors signal 
thus reducing acceleratingtorque.Themotor continues to run at top speed but under closed-loop 
control.
As a target position is approached,the microprocessor lowers the value of the speed-demand 
word; this reduces the voltage at the main summing point, in effect braking the motor. The braking is appliedprogressively until the motor is running at minimum speed.
At that time, the microprocessor orders a switch 
to the position mode, and within 3 to 4ms the 
power stage drives the motor to a null position, 
whereit is held by electronic ”detening”.
Symbol Parameter Value Unit
V
S
Supply Voltage 12 V
V
IA
Analog Inputs Voltage -0.3 to 7 V
V
IL
Logic Inputs Voltage -0.3 to 7 V
V
O
Open Collector Output Current 12 V
I
O
Open Collector Current 10 mA
I
Z
Zener Current 20 mA
T
stg
, Tj Storage Temperature -40to 150 °C
T
amb
Operative Ambient Temperature 0 to 70 °C
ABSOLUTE MAXIMUMRATINGS
PIN CONNECTION (top view)
LAI
L6515
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