LV11961HA Datasheet, PDF (8/14 Pages) ON Semiconductor – Single-phase FAN Motor Driver

LV11961HA
Functional description
- Start Up
In the condition that VTH and RMI level is higher than VCPWM level continuously over 1.5ms (typical),
IC is in the sleep mode. Once VTH level is lower than VCPWM level, IC turns to be active and goes into
the Start-up mode.
In the Start-up mode, PWM duty of OUT1 and 2 in start-up operation is decided by SFS level.
By connecting a capacitor between SFS pin and SGND, the voltage of SFS pin begins to increase soon
after IC booting.
After IC booting, PWM output is in the mode of ...
Driving
( under the condition of SFS > CPWM in the charging period of CPWM )
Regenerating ( the discharging period of CPWM and under the condition of SFS < CPWM in the
charging period of CPWM )
The higher the voltage of SFS pin is, the larger the driving duty is. So, the driving current increases softly
according to the increment of SFS level, as shown in Fig.1.
This function is available not only in IC booting but in restart from lock protection.
VCC
REG
CPWM
SFS
OUT
0.4V(typ)
…Inner clamp level at SFS
2.15V(typ)
(=VREG x 69%)
0.62V(typ)
(=VREG x 20%)
OFF
PWM duty increasing
Fig.1
Clamped duty
(=50%(typ))
The motor should begin to rotate by the increment of driving duty. After 8th FG edge from IC booting or
restart, the control of PWM duty in outputs swithes from SFS level to VTH level, as shown in Fig.2.
VCC
REG
CPWM
VTH
SFS
FG
1
2
3…
…89
OUT
Controlled PWM by SFS
Fig.2
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8
Controlled PWM by VTH