tb6551f TOSHIBA Semiconductor CORPORATION, tb6551f Datasheet - Page 14

• Manufacturer Part Number: tb6551f
• Description: 3-phase Full-wave Sine-wave Pwm Brushless Motor Controller
• Manufacturer: TOSHIBA Semiconductor CORPORATION

Operating Waveform When Driven by Square Wave
Hall signal
Output waveform
Note: At startup, the motor is driven by a square wave when the Hall signals are 5 Hz or lower (f
even during off time. At that time, the upper outputs (U, V, and W) are assigned dead time and turned off
at the timing when the lower outputs are turned on. (T
When the motor is driven by a square wave, acceleration/deceleration is determined by voltage V
motor accelerates/decelerates according to the On duty of T
page 11).
To stabilize the bootstrap voltage, the lower outputs (X, Y, and Z) are always turned on at the carrier cycle
the motor is rotating in the reverse direction as the TB6551F controls it (REV = High).
H
H
H
W
W
U
X
V
Y
U
V
Z
Carrier cycle = f
T
ONL
W
Z
= carrier cycle ´ 8% (s) (Uniformity)
osc
/252 (Hz)
T
ONU
waveform
Enlarged
T
d
14
T
ONL
T
Dead time: T
d
d
varies with input V
ONU
(CW/CCW = = = = Low, OS = = = = High)
(see the diagram of output On duty on
d
= 16/f
osc
e
)
(s) (In more than V
osc
= 4 MHz) and
2002-12-24
TB6551F
e
e
. The
= 4.6 V)