L6235QTR STMicroelectronics, L6235QTR Datasheet - Page 17

• Manufacturer Part Number: L6235QTR
• Description: Motor / Motion / Ignition Controllers & Drivers DMOS 3-Phase Brushless DC Motor
• Manufacturer: STMicroelectronics

Specifications of L6235QTR

• Product Category: Motor / Motion / Ignition Controllers & Drivers
• Rohs: yes

L6235Q
where C
100 kΩ.
By connecting the tachometer pin to an external pull-up resistor, the output signal average
value VM is proportional to the frequency of the Hall effect signal and, therefore, to the
motor speed. This realizes a simple frequency-to-voltage converter. An op amp, configured
as an integrator, filters the signal and compares it with a reference voltage V
the speed of the motor.
Figure 16. Tacho operation waveforms
Figure 17. Tachometer speed control loop
PUL
should be chosen in the range 1 nF … 100 nF and R
V
REF
V
TACHO
H
H
H
V
C
M
1
2
3
REF2
R
Doc ID 018997 Rev 2
3
C
R
1
4
V
DD
t
PULSE
R
V
DD
M
R
1
=
R
PUL
R
V
t
----------------- - V
T
PULSE
DD
2
T
RCPULSE
TACHO
⋅
VREF
C
C
REF1
DD
PUL
H
1
MONOSTABLE
PUL
TACHO
in the range 20 kΩ …
Circuit description
REF
, which sets
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