LB11681H Datasheet, PDF (10/11 Pages) Sanyo Semicon Device – Monolithic Digital IC PWM Three-phase Brushless Motor Driver

LB11681H
6. FG output
The FG pin (pin 13) of this IC is the Hall input U-phase comparator output.
Also, since the FG pin is a open collector output, please connect a pull-up resistance with this pin.
(When the FG output is not used, no a pull-up resistance necessary.)
7. F / R pin (Forward / Reverse)
The F/R pin (pin 15) is a pin for the motor rotation direction switching.
By switching the input level, the direction of rotation of the motor is switchable.
In the high input level, Please do not apply beyond the limits of the voltage of the VR pin (pin 14).
Also, carry out switching of forward / reverse when the motor has stopped.
8. Motor Lock Detection Protection Circuit
The LB11681H incorporates the lock protection circuit to protect the IC and the system from the motor restrained
condition. If the rotor of the brush less motor is not rotated by any reason a certain period of time, the voltage of
the LCK pin is rising. And, when the voltage reaches the lock detection operation voltage the motor is judged as
a restrained condition. Then, the LD pin output (Lock detection output, pin 19) is changed from low to high.
The output transistor becomes a intermittent driving mode at a time.
Therefore, the system is protected by suppressing the heat generation of IC. The setting of the lock detection time
can be adjusted by connecting the capacitance value between the LCK pin (pin 17) and GND.
When the rotor have started, the motor is released from restriction. And, when the motor becomes a normal drive
from a intermitted drive, the LD output goes to low.
When the motor is rotating, the current (discharged current 2) of one-PWM period is discharged every one-pulse
of a Hall FG. In addition, since the LD pin is a open-collector output, please connect a pull-up resistance with the
LD pin (When the LD pin is not used, no a pull-up resistance ).
The relationship between the average time from the lock protection condition to release of the lock protection
condition and the capacity of a LCK capacitor (CLCK) are as follows.
The average time from the lock condition (Stopped of the motor) to the operation of the lock protection function
= (3.8 - *VLCK ) × CLCKF / 4.1µA
The average time from the operation of the lock protection function to release of the lock protection condition
= 2.6 × CLCKF / 2.4µA
Note : *VLCK is the voltage of the LCK pin.
The voltage of the LCK pin changes depending on a rotating speed or the lock protection circuit is
nonfunctional.
When CLCK is 2.2µF,
The average time from the lock condition (Stopped of the motor) to the operation of the lock protection function
= 2.0s
The average time from the operation of the lock protection function to release of the lock protection condition
= 2.4s
9. Control Amplifier
The driving current of the LB11681H can be controlled by the difference in voltage (the difference in voltage is
shown as “∆CTL” from here.) between the VCTL pin (pin 21) and the VREF pin (pin 20).
When ∆CTL increases, the driving current becomes large.
Dynamic range of ∆CTL is about 1V, when the voltage of the CTL pin becomes 1V or more, the IC becomes a
full-driving state. Also, when “∆CTL is a positive relationship, the output is turned off.
No.A0665-10/11