LV11961HA Datasheet, PDF (10/14 Pages) ON Semiconductor – Single-phase FAN Motor Driver

LV11961HA
In case that output turns from PWM operation to constant low side driving, PWM high duty decreases by
12.5% of actual duty every 12.5% of Soft switching term, as shown in Fig.5.
CPWM
VTH _TPWM
(PWM)
TDH TPWM
TPWM
OUT
TDH
TDH x 87.5% TDH x 75% TDH x 62.5% TDH x 50% TDH x 37.5% TDH x 25% TDH x 12.5% TDH x 0%
TSSD
TSSD
(= TSSW x 12.5%)
Term of PWM action
according to VTH level
TSSD
TSSD
TSSD
TINH(L) x 18.75% = TSSW
Term of Soft off switching
TSSD
TSSD
TSSD
Point of phase switching
Fig.5
Similarly in case that output turns from constant low side driving to PWM operation, PWM high duty
increases by 12.5% of actual duty every 12.5% of Soft switching term. However fixed regenerating term is
inserted in 300 usec(typ) after phase switching, as shown in Fig.6.
CPWM
VTH
TPWM
(PWM)
TDH ^TPWM
TPWM
OUT
(TDH x 0%) (TDH x 12.5%) TDH x 25% TDH x 37.5% TDH x 50% TDH x 62.5% TDH x 75% TDH x 87.5%
TDH
TSSD
TSSD
(= TSSW x 12.5%)
Fixed regenerating term
( =300usec(typ) )
TSSD
Point of phase switching
TSSD
TSSD
TINH(L) x 18.75% = TSSW
Term of Soft off switching
Fig.6
TSSD
TSSD
TSSD
Term of PWM action
according to VTH level
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