TDF5140 Philips Semiconductors, TDF5140 Datasheet - Page 15

• Manufacturer Part Number: TDF5140
• Description: Brushless DC motor drive circuit
• Manufacturer: Philips Semiconductors

Philips Semiconductors
The special PG pulse is derived from the negative-going
zero-crossing from the MOT3 output (pin 16). The external
PG signal (PG IN on pin 5) must sense a positive-going
voltage ( 80 mV) within 1.5 to 7.5 commutation periods
before the negative-going zero-crossing in MOT3
(see Fig.8).
The voltage requirements of the PG IN input are such that
an inexpensive pick-up coil can be used as a sensor
(see Fig.9).
Example: If p = 6, then one revolution contains 6
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
grounded, this will result in a 50% duty factor FG signal.
1999 March 15
Brushless DC motor drive circuit
PG/FG
PG IN
MOT3
Fig.8 Timing and the FG and PG IN signals.
tolerance on PG IN
6 = 36
15
Fig.9 Pick-up coil as PG sensor.
2.2 k
22 nF
MBD696
Product specification
MGH319
PG IN
GND2
TDF5140A