LB11868V

No.A1915-10/11

Control timing chart

(ON-time start, Lock protection)

(1) When a stop signal based on the VTH voltage has been input during normal rotation

When the output duty ratio based on the VTH/RMI input drops to below 1% or so, the OTS voltage rises, and when it

reaches VOTS, the standby mode is established, the CT pin discharges, and the S-S pin is charged. In the standby mode,

if the drive mode has been established again by the VTH/RMI input, the rotation is started immediately with soft start.

The CT pin discharges at the same time as the switching of FG. For details on lock protection, refer to (2).

(2) When a stop signal based on the VTH voltage has been input while the fan is constrained

When the fan is constrained, the CT pin voltage rises, and when it reaches VCTH, the lock protection mode is

established, and OUTP is set to OFF and RD is set to OFF.

When the lock protection mode is established, the CT pin discharges, and when VCTL is reached, restart (soft start) is

initiated. When rotation is started and the FG signal is switched, RD is set to low.

Note: RD is also set to low when the standby mode is established when locked.

GND

VCPWMH

VCPWML

CPWM

GND

GND

OTS

CT

FG

RD

VOTS

VCTL

VCTH

RMI voltage

S-S voltage

VTH voltage

Fan restraint

GND

VCPWMH

VCPWML

CPWM

GND

GND

OTS

CT

FG

RD

RMI voltage

VTH voltage

S-S voltage

VOTS

VCTH