L9909 Datasheet, PDF (1/9 Pages) STMicroelectronics – DC MOTOR DRIVER WITH POSITION CONTROL

®
L9909
DC MOTOR DRIVER WITH POSITION CONTROL
DESCRIPTION
Oscillator.
The output current at ROSC pin is mirrored to
COSC pin with a proper direction according to its
voltage slope.
The triangular wave form at COSC pin, being
compared with a threshold, defines the PWM duty
cycle at the motor driver output M+ and M-.
The oscillator also supplies the time base for the
switch off and switch on delays and the Time Out
Counter.
The typical oscillator period is:
Tosc = 7.04 x Rosc x Cosc
MInidip
ORDERING NUMBER: L9909
BLOCK DIAGRAM
V cc
Vcc
Current ratio = 1 : 2
1
2
Vcc
01
150KΩ
01
150KΩ
+-
- + _OP1
| 5 Verr|
COMP7
Td_on
switch on
DELAY
+
VR7 =
7.5% Vcc
COUN TER
START
RES
TIME OUT
Vcc
+
COMP1
Td_off
switch off
VR3=6.6% Vcc
START
STOP
-
D ELAY
VR4 = 1.5V
+ ^{COMP4 Td_pwm}
pwm
DELAY
STOP
DIRECTION
PWM
VR2=56.6%Vcc
Tck
DRIVE R
VR3=6.6%Vcc
VR5 = 6.6% Vcc
TEMP.
SENSE
over
temp.
CONT ROL
OFF
Td_ov_2
( 1ms)
Vcc
VOLT.
over volt.
over volt.
SENSE
D ELAY2
OFF
Vcc
Td_ov_1
(130 µs)
35V
VR2 =
56.6% Vcc
VR3 =
6.6% Vcc
COMP2
S
Tck
FF
R
over volt.
DELAY 1
curr.
limit
curr.
limit
COMP3
Vcc
I
35V
M+
open
open
10V
Q
M-
16V VR2 =
I
56.6% Vcc
VR3 =
6.6% Vcc
OP8 VR8 =
+ _{14.2% Vcc}
I ^{curr. -}
Latch
sense
curr.
curr.
IN
limit
limit
7V
OSCILLATOR
ROSC
GND
February 2001
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