l9909 STMicroelectronics, l9909 Datasheet - Page 6

• Manufacturer Part Number: l9909
• Description: Dc Motor Driver With Position Control
• Manufacturer: STMicroelectronics

L9909
Figure 6. Recommended Application Diagram for Positive Control
Figure 7. Recommended Application Diagram for Direction Control
Over Current Protection.
The driver output pins (M+ and M-) are over cur-
rent protected by 4 separate linear current limit-
ers, one for each of the 4 power output transis-
tors. The output drivers resume normal operation
as soon as the over current is removed.
Motor Over Voltage Protection.
The motor is over voltage protected by switching
off (to Hi-Z) the M+ and M- output drivers, when
Vcc rises above the 19V typ. over voltage shut
down threshold.
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DIR
GROUND
POWER
GROUND
DIR
Threshold
Voltage
POWER
Protection
Resistor
10KΩ
20KΩ
20KΩ
Protection Diode
Reverse Battery
Protection
Network
1K Ω
EMI
Protection Diode
Reverse Battery
Capacitors
Protection
1nF
1KΩ
EMI
1nF
1nF
1nF
VCOM
VFB
VCOM
VFB
OSCILLATOR
U709
ROSC
Rosc
27KΩ
OSCILLATOR
U709
ROSC
-
+
Rosc
27KΩ
-
+
-
+
COSC
Cosc
10nF
VCC
+
-
COSC
Cosc
10nF
VCC
Over Temperature Protection.
The chip is over temperature protected by switch-
ing off (to Hi-Z) the M+ and M- output drivers.
Power Supply Transient Protections.
The device provides over voltage suppression for
fast Vcc voltage transients (Fig. 5). The Vcc is
clamped at typ. 70V by turning on all four, bridge
connected, power output transistors. They are
roughly subjected to equal currents and voltages
for even transient energy distribution.
The over voltage suppression is deactivated for
slow Vcc voltage transients (Fig. 4) by raising the
Vcc voltage clamp at typ. 80V.
GND
M+
M-
GND
100nF
M+
M-
100nF
M
DC
MOTOR
M
DC
MOTOR
100nF
100nF
1nF
1nF