TDA5141A Philips Semiconductors, TDA5141A Datasheet - Page 16

• Manufacturer Part Number: TDA5141A
• Description: Brushless DC motor drive circuit
• Manufacturer: Philips Semiconductors

Philips Semiconductors
Product specification
Brushless DC motor drive circuit
TDA5141
Fig.12 Timing and the FG and PG IN signals.
The special PG pulse is derived from the negative-going
zero-crossing from the MOT3 output. The external PG
signal (PG IN) must sense a positive-going voltage
( 80 mV) within 1.5 to 7.5 commutation periods before the
2.2 k
negative-going zero-crossing in MOT3 (see Fig.12).
PG IN
The voltage requirements of the PG IN input are such that
22 nF
an inexpensive pick-up coil can be used as a sensor
(see Fig.13).
GND2
MBD696
Example: If p = 6, then one revolution contains
6
6 = 36 commutations. The tolerance is 6 periods, that
is 60 degrees (mechanically) or 6.67 ms at 1500 rpm.
If a PG sensor is not used, the PG IN input must be
Fig.13 Pick-up coil as PG sensor.
grounded, this will result in a 50% duty factor FG signal.
April 1994
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