lb11691 Sanyo Semiconductor Corporation, lb11691 Datasheet - Page 15

• Manufacturer Part Number: lb11691
• Description: Pre-driver Ic For Brushless Motor Drive In Electric Bicycles
• Manufacturer: Sanyo Semiconductor Corporation

9. RC and FV circuits
10. Power stabilization
11. Stabilizing the regulator output voltage
12. Lock protection circuit
13. Forward/backward operation
14. FAIL Hall input
The RC pin is to set the pulse width (“H” time) generated in the FV pin for both edges of HP signal (Hall three-phase
composite signal). Connect a resistor and capacitor between RS and VE pins and between this pin and GND
respectively and set the pulse width. The pulse width TRC can be approximated by the following equation.
Connect the smoothing circuit comprising a resistor and capacitor, as shown in the right,
to the FV pin. Select the 25kΩ or more resistor. The capacitor must have the capacitance
ensuring sufficient smoothing of FV voltage when the motor rotation speed is low.
Assume that the HP signal frequency at the maximum motor speed is fHP (Hz). Set so
that the following equation is established :
In this case, the FV voltage changes from 0 to about 5V according to the motor speed.
The FV voltage can be used as a signal for speed meter indication of analog or level
meter IC or speed return.
If FV output is not to be used, connect the RC pin to GND and keep the FV pin open.
This IC is of a switching drive type, causing a state in which the power line is readily displaced. It is therefore necessary
to connect the capacitor with sufficient capacity between the V CC pin and GND for stabilization.
When a diode is to be inserted into the power line to prevent breakdown due to reverse connection of power supply, the
power line tends to be displaced readily. It is therefore necessary to select the larger capacity.
Connect the capacitor of 0.1μF or more between V5 pin (5V : control circuit
power supply) or V12 pin (12V : lower drive output circuit power supply) and
GND. Wire the capacitor GND as near to IC GND pin as possible.
Each output can output the current of 30mA or less to the outside of IC. Due care
must be taken however because IC heat generation increases. If this is used in the
Hall IC power supply and presents a problem of heat generation, connect Tr as
shown in the right so that Tr receives heat generation.
The lock protection circuit is incorporated to protect IC and motor when the motor is locked. When the Hall input
signal is not changed over for a certain period while the motor is being driven, the output on one side (UL, VL, WL) is
turned OFF. The time is set with the capacitor capacitance connected to the CSD pin.
Connection of the 0.01μF capacitor ensures the protection period of about 0.3 seconds (the drive is turned OFF when
one cycle of Hall input signal exceeds this set time). Be sure to set the time with sufficient allowance, so that the
protection circuit is not activated at normal motor startup. For the capacitor, use 4700pF or more. To cancel the lock
protection state, take any one of following steps :
For forward/backward changeover during running, the measure is taken to prevent through current at the output
(through current caused by the output Tr OFF delay time at a time of changeover). However, changeover during
running causes the current exceeding the current limit to flow through the output Tr due to the motor coil resistance and
motor counter electro-motive force. It is therefore necessary either to select the external output Tr that does not suffer
breakage by this current or to design changeover with the motor speed reduced to a certain degree.
The output becomes “L” in following states with the open collector output :
TRC (S) ≈ 1.1 × R × C
TRC (S) ≤ 1 ÷ (2 × fHP)
Set time (s) ≈ 30 × C (μF)
• Resetting,
• Maintaining the output duty 0% state by TOC input for the period of tCSD × 2,
• Re-applying the power.
• At abnormal Hall input
• When the low-voltage protection circuit is activated
• When the lock protection circuit is activated
• When the overheat protection circuit is activated
LB11691
V5 pin or
V12 pin
RC pin
FV pin
V CC
Hall IC power supply
To V5 pin
No.A0879-15/21
FV voltage