BU6909AGFT Datasheet, PDF (12/21 Pages) Rohm – Built in HALL element

BU6909AGFT
Datasheet
Quick start function
This series has an integrated quick start function. When the PWM signal is input, this function can start up the motor at
once regardless of the detection time of the lock protection function. (Consider HALL amp gain select time. Reference is
shown in Figure 24.)
Stand-by mode
Stand-by function turns off the circuit when the time of PWM=L has elapsed in order to reduce stand-by current. The circuit
current consumption during stand-by mode is specified at the parameter “Circuit current 2” of the electrical characteristics.
Figure 24 shows the timing diagram of stand-by mode and quick start function.
The 0% detection time before the IC changes to stand-by mode is variable depending on the input PWM duty. This is
because of the built in LPF at the PWM terminal. As an example, Figure 25 shows the characteristic curve of 0% detection
time and input PWM duty for a 25kHz input PWM frequency.
Figure 24. Stand-by mode and quick start function
1 00
80
60
40
20
0
0.0
1.0
2.0
3.0
4.0
0% detection time : t₀ [ms]
Figure 25. Characteristic curve of 0% detection time and input PWM duty at 25kHz
Lock protection and automatic restart
Motor rotation is detected by HALL signal, while lock detection ON time (t_ON) and lock detection OFF time (t_OFF) are set by
IC internal counter. External part (C or R) is not required. Timing chart is shown in Figure 26.
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TSZ22111・15・001
Figure 26. Lock protection timing chart
12/18
TSZ02201-0H1H0B101190-1-2
28.Oct.2014 Rev.002