lv8829lf Sanyo Semiconductor Corporation, lv8829lf Datasheet - Page 12

• Manufacturer Part Number: lv8829lf
• Description: For Brushless Motor Drive Pwm Driver Ic
• Manufacturer: Sanyo Semiconductor Corporation

6. Power Saving Circuit (Start/Stop circuit)
7. Power Supply Stabilization
8. VREG Stabilization
9. Charge pump Circuit
10. Metal part at the rear of the IC
To save power when the LV8829LF is in the stop state, most of the circuit is stopped, aiming at reducing current
consumption. If the Hall bias pin is used, the current consumption in the power-saving mode will be approximately
700μA. Even in the power-saving mode, a 5V regulator voltage is output. Also, in the power-saving mode, the IC is in
a short break state. (lower-side shorted)
This IC generates a large output current, and employs a switching drive method, so the power supply line level can be
disturbed easily. For this reason, it is necessary to connect a capacitor (electrolytic) of sufficient capacitance between
the V CC pin and ground to ensure a stable voltage. Connect the ground side of the capacitor to the PGND pin, which is
the power ground, as close as possible to the pin. If it is not possible to connect a capacitor of sufficiently large
capacitance close to the pin, connect a ceramic capacitor of approximately 0.1μF to the vicinity of the pin.
If diodes are inserted in the power supply line to prevent IC destruction resulting from reverse-connecting the power
supply, the power supply lines are even more easily disrupted. And even larger capacitor is required.
To stabilize the VREG voltage, which is the power supply for the control circuit, connect a capacitor of 0.1μF or larger.
Connect the ground of this capacitor as close as possible to the control block ground (SGND pin) of the IC.
The voltage is stepped-up by the charge pump circuit, causing the gate voltage of the upper-side output FET to be
generated. The voltage is stepped-up by capacitor CP connected between pins CP1 and CP2, causing charge to
accumulate in capacitor CG connected between pins VG and V CC . The capacitance of CP and CG must always satisfy
the following relationship.
Charging and discharging of capacitor CP take place based on a frequency of 100kHz. When the capacitance of
capacitor CP is large, the current supply capability of power supply VG will increase. However, if the capacitance is
too large, the charging and discharging operations will be insufficient. The larger the capacitance of capacitor CG, the
more stable voltage VG will become. However, if the capacitance is made too large, the period during which voltage
VG is generated when the power is switched ON will become long, so caution is necessary.
The capacitance settings of CP and CG should be the following.
The metal part at the rear of the IC (exposed die-pad) constitutes the sub ground of the IC, so connect it to the control
ground (SGND pin) and power ground pin (PGND) at points close to the IC.
CG ≥ 4 × CP
CP = 0.01μF
CG = 0.1μF
LV8829LF
No.A1801-12/13