LB11697V Datasheet, PDF (13/14 Pages) Sanyo Semicon Device – Monolithic Digital IC Brushless Motor Driver IC

LB11697V
While the motor is turning, the discharge pulse signal (generated once for each Hall input period) that is created by
combining the Hall inputs internally in the IC discharges the CSD pin external capacitor. Since the CSD pin voltage
does not rise, the constraint protection circuit does not operate.
When the motor is physically constrained, the Hall inputs do not change and the discharge pulses are not generated.
As a result, the CSD pin external capacitor is charged by a constant current of 2.25 µA to about 3.0 V, at which
point the constraint protection circuit operates. When the constraint on the motor is released, the constraint
protection function is released.
Connect the CSD pin to ground if the constraint protection circuit is not used.
9. Forward/Reverse Direction Switching
This IC is designed so that through currents (due to the output transistor off delay time when switching) do not flow
in the output when switching directions when the motor is turning. However, if the direction is switched when the
motor is turning, current levels in excess of the current limiter value may flow in the output transistors due to the
motor coil resistance and the motor back EMF state when switching. Therefore, designers must consider selecting
external output transistors that are not destroyed by those current levels or only switching directions after the speed
has fallen below a certain speed.
10. Handling Different Power Supply Types
When this IC is operated from an externally supplied 5 V power supply (4.5 to 5.5 V), short the V_CC pin to the
VREG pin and connect them to the external power supply.
When this IC is operated from an externally supplied 12 V power supply (8 to 17 V), connect the V_CC pin to the
power supply. (The VREG pin will generate a 5 V level to function as the control circuit power supply.)
11. Power Supply Stabilization
Since this IC uses a switching drive technique, the power supply line level can be disturbed easily. Therefore
capacitors with adequate capacitance to stabilize the power supply line must be inserted between V_CC and ground.
If diodes are inserted in the power supply lines to prevent destruction if the power supply is connected with reverse
polarity, the power supply lines are even more easily disrupted, and even larger capacitors are required.
If the power supply is turned on and off by a switch, and if there is a significant distance between that switch and the
stabilization capacitor, the supply voltage can be disrupted significantly by the line inductance and surge current into
the capacitor. As a result, the withstand voltage of the device may be exceeded. In application such as this, the surge
current must be suppressed and the voltage rise prevented by not using ceramic capacitors with a low series
impedance, and by using electrolytic capacitors instead.
12. VREG Stabilization
To stabilize the VREG voltage, which is the control circuit power supply, a 0.1 µF or larger capacitor must be
inserted between the VREG pin and ground. The ground side of this capacitor must connected to the IC ground pin
with a line that is as short as possible.
No.8412-13/14