TB6520P/PG

2006-3-6

4

FUNCTIONAL DESCRIPTION

1. Crystal oscillator (XT, XT )

The crystal oscillator is connected as shown in the following diagram:

The start transfer frequency fst and maximum transfer frequency fmx depend upon crystal oscillation

frequency fx. Please make sure of the start operation in determining your frequency.

PWM chopping frequency fp is also determined as follows:

fp = fx / 256

2. Lead angle control

Operated at 0 lead angle during forced start transfer, and automatically switched to 15 lead angle upon

normal transfer.

3. PWM Duty Control

PWN duty is controlled through A−D conversion of the

analog voltage that is input to the DUTY pin.

DUTY 0%

in the figure to the right

DUTY 100% (127 / 128)

4. FG output

FG, which represents the frequency of motor rotation, is output from the position detection signal input.

When stopped : LOW

When start is forcibly transferred : LOW

When normally rotated 1−pulse signal is output in one electric cycle.

4−polar motor

2 pulses / rotation

8−polar motor

4 pulses / rotation