L6228 STMicroelectronics, L6228 Datasheet - Page 20

• Manufacturer Part Number: L6228
• Description: DMOS DRIVER FOR BIPOLAR STEPPER MOTOR
• Manufacturer: STMicroelectronics

L6228
Output Current Capability and IC Power Dissipation
In Fig. 24, 25, 26 and 27 are shown the approximate relation between the output current and the IC power dis-
sipation using PWM current control driving a two-phase stepper motor, for different driving sequences:
– HALF STEP mode (Fig. 24) in which alternately one phase / two phases are energized.
– NORMAL DRIVE (FULL-STEP TWO PHASE ON) mode (Fig. 25) in which two phases are energized
– WAVE DRIVE (FULL-STEP ONE PHASE ON) mode (Fig. 26) in which only one phase is energized at
– MICROSTEPPING mode (Fig. 27), in which the current follows a sine-wave profile, provided through
For a given output current and driving sequence the power dissipated by the IC can be easily evaluated, in order
to establish which package should be used and how large must be the on-board copper dissipating area to guar-
antee a safe operating junction temperature (125°C maximum).
Figure 24. IC Power Dissipation versus Output Current in HALF STEP Mode.
Figure 25. IC Power Dissipation versus Output Current in NORMAL Mode (full step two phase on).
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during each step.
each step.
the V
ref
pins.
P
P
D
D
[W ]
[W]
10
10
8
6
4
2
0
8
6
4
2
0
0
0 0.25 0.5 0.75 1 1.25 1.5
0.25 0.5 0.75 1
NORM AL DRIVE
HALF STEP
I
I
OUT
OUT
[A ]
[A]
1.25 1.5
I
I
A
B
I
I
A
B
Test Conditions:
Supply Voltage = 24V
Test Conditions:
Supply Volt age = 24 V
I
OUT
I
No PWM
f
OUT
SW
I
No PWM
f
= 30 kHz (slow decay)
OUT
SW
= 30 kHz (slow decay)
I
OUT