TMC603A Datasheet, PDF (42/44 Pages) TRINAMIC Motion Control GmbH & Co. KG. – Three phase motor driver with BLDC back EMF commutation hallFX™ and current sensing

TMC603A DATA SHEET (V. 1.15 / 2009-Nov-19)
42
8.3 Programming a block commutation for hallFX™
In order to operate a motor using a hall sensor or hallFX™, the user processor needs to provide a
commutation decoder. Also, commutation checking makes sense, to determine the direction of
operation.
The commutation logic decodes the hall sensor signal to provide standard block commutation
patterns. There are six different valid hall sensor codes. Each of these represents a different position
of the rotor. In order to turn the rotor, a magnetic field has to be provided by the motor’s stator coils,
which is shifted by an commutation angle of +90° or by -90° for CW respectively CCW rotation. Since
the hall sensor provides a 60° resolution, the commutation logic can keep the phase angle always
between +60° to +120° respectively -60° to -120°. The mean value is the desired +/-90°.
In block commutation, one motor phase terminal is open (Z) at each phase pattern, while the current
flows through the other two phases. One of these two phases is switched to the motor supply voltage
(1), the other one to GND (0). For hallFX™, both of these are chopped between (Z) and (1),
respectively (Z) and (0) in order to modulate the motor power. The commutation table shows the block
commutation decoder logic.
Hall pattern H1 H2 H3 U1 V1 W1 U0 V0 W0
1
110Z01Z10
2
01010Z01Z
3
0111Z00Z1
4
001Z10Z01
5
10101Z10Z
6
1000Z11Z0
Z: Coil output open
0: Coil output pulled low or negative PWM
1: Coil output pulled high or positive PWM
U0, V0, W0: Pattern with positive direction (dir = 0). This is the pattern for hallFX™ in both directions.
U1, V1, W1: Pattern with negative direction (dir = 1)
DIR=1
VW
U
U
VW
6
5
4
3
2
1
U
U
DIR=0
W
V
W
V
1
2
3
4
5
6
figure 22: commutation sequence
8.4 Driving a DC motor with the TMC603
The TMC603 can also be used for DC motor applications, using a full bridge or a half bridge for motor
PWM operation with or without reverse direction operation. For single half bridge applications, all
TMC603 gate drivers can be paralleled, taking advantage of the three time increase in gate drive
capability up to 450mA. This way a motor current of up to 100A can be driven. The drive system can
use the shunt less current sensing capability for best efficiency. A Schottky diode across the non-
chopped transistor optimizes slopes and electromagnetic emission characteristics (see chapter 5.2.8).
Copyright © 2009 TRINAMIC Motion Control GmbH & Co. KG