DRV8307_15 Datasheet, PDF (14/34 Pages) Texas Instruments – DRV8307 Brushless DC Motor Controller

DRV8307
SLVSCK2 – APRIL 2014
www.ti.com
State 1 2 3 4 5 6 1 2 3 4 5 6 1
Hall U
Hall V
Hall W
Phase U HS
Phase U LS
(1)
(1)
Phase V HS
Phase V LS (1)
(1)
(1)
Phase W HS
Phase W LS
(1)
(1)
Figure 6. Standard 120° Commutation (DIR = 0)
8.3.4.2 120° Single-Hall Commutation
To generate commutation timing for single-Hall commutation, a digital timer is used to create a clock that runs at
960× the Hall sensor frequency. Only one Hall sensor input, HALL_U, is used for commutation; this eliminates
any torque ripple caused by mechanical or electrical offsets of individual Hall sensors.
Single-Hall commutation is only enabled when the motor is operating at a nearly constant speed or speed-locked
condition. To control this function, logic is used to determine when the speed is constant. This logic generates
the LOCK signal. The LOCK signal is also output on the LOCKn terminal.
Until LOCK goes active (for example, at start-up, stop, or application of a sudden load that causes motor speed
to drop very quickly), standard 120° commutation is used requiring all three Hall sensors.
Timing of 120° single-Hall commutation is essentially the same as standard 120° commutation shown previously.
However, there are small time differences in when the transitions occur.
8.3.5 Braking
Motor braking can be initiated by the BRAKE terminal.
Table 2. Brake Behavior
BRAKE Terminal
0
1
Resulting Function
Not brake
Brake
14
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