LB11690H SANYO [Sanyo Semicon Device], LB11690H Datasheet - Page 15

• Manufacturer Part Number: LB11690H
• Description: Pre-Driver IC for Brushless Motor Drive in Electric Bicycles
• Manufacturer: SANYO [Sanyo Semicon Device]

Continued from preceding page.
9. RC and FV Circuits
10. Power Supply Stabilization
The IC remains in the reset state as the RES pin voltage goes from 0 V to about
1.5 V. Since the reset circuit has a hysteresis of about 0.23 V, the IC will not
return to the reset state unless the RES pin voltage falls to under 1.27 V.
In addition to the initial reset, the RES pin can also be used to apply a reset
when the control voltage is low as shown in figure 1. This circuit sets all the
drive outputs to the off state when the control voltage reaches about 0.67 V
(1.27 V - V
In the state when 0% duty (1.2 V or lower) is set up with just the control
voltage, the circuit will function as a brake if the motor is operated in the
reverse direction. Thus the circuit shown here can be useful if braking is not
required during reverse rotation. If the control voltage cannot be lowered below
1 V, a circuit such as that shown in figure 3 can be used.
Applications that use a thermistor to detect the temperature and prevent thermal
destruction of the FETs can also be considered. The FETs can be protected by
adjusting the value of the external resistor connected as shown in figure 2.
Figure 4 shows how to combine this application circuit with the application
circuit shown in figure 3.
The RC pin sets the pulse width (the high-level period) of the signal generated at the FV pin at each edge (both rising
and falling edges) of the HP signal (the three-phase synthesized Hall signal). The pulse width is set by connecting a
resistor between the RC pin and the V5 pin and a capacitor between the RC pin and ground. The pulse width, TRC,
can be calculated with the following formula.
The FV pin is normally smoothed with an RC circuit such as that shown in the
figure. A resistor with a value of 25 kΩ or higher must be used. Choose a
capacitance such that the FV voltage is smoothed adequately at low motor speeds.
Normally, TRS is set to meet the following condition when the HP signal
frequency at the highest motor speed is fHP (Hz).
Here, the FV voltage will vary from 0 to about 5 V according to the motor speed.
The FV voltage can be used for speed feedback or speedometer display by using an
analog meter or level meter IC.
If the FV output is not used, the RC pin must be connected to ground and the FV
pin must be left open.
Since this IC uses a switching based drive technique, it can easily cause voltage fluctuations in the power supply
lines. This means that capacitors fully adequate to stabilize the supply voltage must be inserted between the V
and ground.
If diodes are inserted in the power supply lines to prevent damage when the power supply is connected with the
polarity reversed, voltage fluctuations in the power supply lines can occur even more easily. In such applications,
even larger capacitors are required.
TRC (seconds) 1.1 R C
TRC (seconds) ≤ 1 ÷ (2 f
BE
To the control voltage (1 V to 4 V)
Figure 3
). Here, the reset release voltage is about 0.9 V (0.67 V + 0.23 V).
RES
HP
)
EI+
LB11690, 11690H
RES
Figure 4
To the V5 pin
To the control voltage (1 V to 4 V)
RES pin
Figure 1
Figure 2
To the V5 pin
RC pin
FV pin
RES pin
Thermistor
To the V5 pin
EI+
To the control voltage
To the V5 pin
EI+ pin
No. 7543-15/19
FV voltage
CC
pin