LC79451KB Datasheet, PDF (37/38 Pages) ON Semiconductor – Controller and Driver

10-3. Power Supply OFF Sequence
LC79451KB
When you turn off VDD power supply, the discharge of a stored electric charge is recommended. This is because
image may change when an electric charge is left in the external capacitor of VOUT2 and VOUT3.
You can discharge a stored electric charge in the following procedures when you cannot meet a condition of
Cf.6-6.
(1) Operate charge-pump if VOUT0 < 2.0V or VOUT1 < 4.0V.
(2) Stop charge-pump.
(3) Operate discharge. (control register 2: DISCON = 1)
(4) Turn off VDD power supply.
You can maintain a discharge state when you turn off VDD power supply during discharge operation as
RESET = VDD.
10-4. Parasitic Circuit between Charge-pump Pins and Power Supply Pins
Between charge-pump pins and power supply pins, parasitic diode is connected equivalently to constitute a circuit.
VOUT2 (+15V)
VOUT1 (+5V)
VOUT0 (+2.5V)
VDD2 (+1.8V to +3.6V)
VDD (+1.6V to +3.6V)
VSS (0V)
VOUT3 (-15V)
Fig.19. Parasitic circuit diagram between pin
No.A2223-37/38