TB6631FNG Datasheet, PDF (16/28 Pages) Toshiba Semiconductor – 3-Phase Full-Wave Sine-Wave PWM Brushless Motor Controller

Generation Timing of Modulation Wave
TB6631FNG
Timing of generating modulation wave and the reset can be selected by the TEST2 terminal.
TEST2
L
H
Function
Generating modulation wave every
electric angle of 360°
Generating modulation wave every
electric angle of 60°
When TEST2 = L
The position signals from Hall sensors are modulated, and the modulated signals are then compared against a
triangular waveform to generate a sinusoidal PWM waveform.
The counter measures the period from a given falling edge of the HU input to its next falling edge (360 electrical
degrees). This period is then used as 360° phase data for the next modulation.
A total of 192 ticks comprise 360 electrical degrees; the length of a tick equals 1/192nds the time period of the
immediately preceding 360° phase.
(Note)
HU
T1
T2
T1’
T2’
SU
SV
SW
T1’ = T1
T2’ = T2
In the above diagram, the modulated waveforms have an interval (T1’) equal to the interval between a falling
edge of HU to its next falling edge (T1) of the previous cycle. If there is not an HU falling edge before T1’ ends, T2’
becomes equal to T1’ until the next falling edge of HU.
Modulation is reset on each falling edge of HU, which occurs every 360 electrical degrees. While the motor is
accelerating or decelerating, the modulated waveform becomes discontinuous upon each reset.
Note: In the above diagram, HU is shown as square waveforms for the sake of simplicity.
16
2015-10-08