ATA6844-DK Atmel, ATA6844-DK Datasheet - Page 3

• Manufacturer Part Number: ATA6844-DK
• Description: Power Management IC Development Tools BLDC Motor Drvr Brd
• Manufacturer: Atmel
• Type: Motor / Motion Controllers & Driversr

Specifications of ATA6844-DK

• Rohs: yes
• Product: Development Kits
• Tool Is For Evaluation Of: ATA6844, ATmega32M1, ATmega32U2
• Input Voltage: 3.3 V, 5 V, 12 V
• Description/function: Atmel ATA6844-DK BLDC Motor Control Kit
• Interface Type: LIN, UART, USB
• Factory Pack Quantity: 1

3. Theories of BLDC Operation
9236A–AUTO–08/11
Brushless DC motors are used in a growing number of applications because of several advan-
tages, including reduced noise, extended service life with no brush wear, reduced noise, a
good weight/size-to-power ratio, and their suitability for hazardous operation environment sce-
narios (with flammable product).
Motors of this kind have slight rotor inertia. Coils are attached to the stator. Commutation is
controlled by electronics using position sensor feedback or back electromotive force
(back-EMF) measurements.
The BLDC motor stator basically includes three coils which can be replicated to reduce torque
ripple. In the same way, rotor basically includes permanent magnets, composed of one to
more pairs of poles. This also affects step size (see
either by using three Hall sensors, each spread at 120° around the stator or a greater subdivi-
sion of higher rotor pole pair counts. Or Position can be estimated by measuring the voltage
induced by the back electromotive force, determining the voltage zero crossing.
Figure 3-1.
BLDC motor operation can be simplified by considering only three coils and one pair pole.
Phase’s commutation depends on the position with the Hall sensor value the easiest way to
detect it. When motor coils are supplied with energy, a magnetic field is created which sets the
rotor in motion. The most elementary commutation driving method is an on-off scheme: a coil
is either conducting or not. Only two coils are supplied at the same time, the third is floating.
This is referred to as trapezoidal commutation or block commutation.
Figure 3-2.
C
Three Coil BLDC Motor, 1 and 2 Pair Poles
Power Stage
A
N
S
B
H1
L1
H2
L2
Atmel ATA6843/ATA6844
Figure
H3
L3
C
3-1). Position can be estimated
A
B
C
S
A
N
N
S
B
3