bh6799fvm ROHM Co. Ltd., bh6799fvm Datasheet - Page 9

• Manufacturer Part Number: bh6799fvm
• Description: Dc Brushless Motor Driver Series For Cooling Fans Low-voltage Single-phase Full-wave Dc Brushless Fan Motor Drivers
• Manufacturer: ROHM Co. Ltd.

●Description of operations
Function table
1) Lock protection and automatic restart circuit ＜BD6989FVM、BH6799FVM、BH6789FVM＞
Lock protection and auto
restart circuit
Soft switching
PWM speed control
FG output
AL output
set by IC internal counter. External part (C or R) is not required. Timing chart is shown in Fig.25.
When H level duty of PWM input signal is close to 0%, lock protection function does not work at an input frequency
slower than 15Hz (typ.), therefore enter a frequency faster than 20Hz.
Motor rotation is detected by hall signal, and lock detection ON time (TON) and lock detection OFF time (TOFF) are
＊ In the case of BD6989FVM, lock protection function is turned off when the time of PWM = L has elapsed more
＜BD6989FVM,BH6799FVM＞
Lock protection function
Control signal (internal signal)
than 66.5 ms (typ.) in order to disable lock protection function when the motor is stopped by PWM input signal.
PWM
＜BH6789FVM＞
OUT1
OUT2
Fig.26 PWM signal and lock protection operation ＜BD6989FVM＞
H+
FG
AL
BD6989FVM
Motor
locking
ON
〇
〇
〇
〇
Lock
detection
66.5ms(typ.)
Output Tr OFF
Fig.25 Lock protection timing chart
Idling
BH6799FVM
Hi (Open collector)
Depends on hall signal.
(H in this figure)
〇
〇
〇
9/16
TON
ON
BH6789FVM
OFF
〇
〇
〇
Lock
release
Recovers normal
operation.
BH6766FVM
〇
〇
ON
Reference
page
P.10
P.11
P.13
P.13
P.9