LC79451KB

No.A2223-37/38

10-3. Power Supply OFF Sequence

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.

Fig.19. Parasitic circuit diagram between pin

VOUT2 (+15V)

VOUT1 (+5V)

VOUT0 (+2.5V)

VSS (0V)

VOUT3 (-15V)

VDD2 (+1.8V to +3.6V)

VDD (+1.6V to +3.6V)