LC79451KB

No.A2223-19/38

6-3. Mode selection for control of charge-pump and oscillator

Control mode of charge-pump and oscillator is selected by the following.

• Automatic charge-pump mode

• Manual charge-pump mode

6-3-1. Automatic Charge-pump Mode

Automatic charge-pump mode automatically controls stopping from operating charge-pump and oscillator.

Charge-pump and oscillator stop while waveform output standby period. Automatic charge-pump mode is low power

than manual charge-pump mode, though charge-pump takes time to start.

<Flow of operation>

Charge-pump and oscillator start operating with START Flag =1. Waveform is output automatically with finishing of

charge-pump rising period. Charge-pump and oscillator stop automatically after finishing of waveform output period,

and START Flag is automatically canceled.

Charge-pump and oscillator start operating with HVON Flag =1. Charge-pump and oscillator stop automatically after

charge-pump rising period, and HVON Flag is automatically canceled.

Fig.9. Flow of automatic charge-pump mode

6-3-2. Manual Charge-pump Mode

Manual charge-pump mode automatically controls stopping from operating charge-pump and oscillator.

Charge-pump and oscillator are active while waveform output standby period. Manual charge-pump mode is high

power than automatic charge-pump mode, though charge-pump takes no time to start.

<Flow of operation>

Charge-pump and oscillator start operating with HVON Flag =1. The state shifts to waveform output standby period

with finishing of charge-pump rising period. While waveform output standby period, waveform output is started with

START Flag =1, and START Flag is automatically canceled after finishing of waveform output period. Charge-pump

and oscillator stop when HVON Flag is canceled.

Fig.10. Flow of manual charge-pump mode

START Flag

HVON Flag

operation

Charge-pump

rising period

Waveform output

period

Waveform output

standby period

Charge-pump

rising period

Charge-pump rising

waiting time

Oscillator

Charge-pump

Output Driver

operation

operation

operation

Output Driver

operation

Charge-pump

rising period

Waveform output

standby period

Waveform output

period

START Flag

HVON Flag

Waveform output

standby period

Oscillator

Charge-pump