BU6909AGFT Datasheet, PDF (10/21 Pages) Rohm – Built in HALL element

BU6909AGFT
Datasheet
PWM control
Rotation speed of motor can be changed by controlling ON/OFF of the upper output depending on the duty of the input
signal to PWM terminal. When PWM terminal is open, H logic is applied. Output PWM frequency is 50 kHz (Typ). This IC is
not direct PWM. Hence, input PWM frequency is not equal to output PWM frequency. Figure 21 shows the characteristic of
input PWM duty and output PWM duty.
PWM terminal has a built in digital low pass filter (LPF). Output PWM duty has 3.5ms (Max) transitional time from the point
of change in input PWM duty, this is caused by the LPF characteristic (reference is shown in Figure 22). Additionally, Input
PWM uses frequencies above 5 kHz.
1 00
80
60
40
20
0
0 20 40 60 80 100
Input PWM DUTY [%]
Figure 21. Characteristic of input PWM DUTY and output PWM DUTY
Figure 22. Timing chart of PWM control
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TSZ22111・15・001
10/18
TSZ02201-0H1H0B101190-1-2
28.Oct.2014 Rev.002