LC79451KB Datasheet, PDF (19/38 Pages) ON Semiconductor – Controller and Driver

LC79451KB
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.
Charge-pump
rising period
Waveform output
period
Waveform output
standby period
Charge-pump
rising period
Oscillator
Charge-pump
Output Driver
operation
operation
operation
START Flag
HVON Flag
Charge-pump rising
waiting time
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.
Charge-pump
rising period
Waveform output
standby period
Waveform output
period
Waveform output
standby period
Oscillator
Charge-pump
Output Driver
operation
operation
START Flag
HVON Flag
Fig.10. Flow of manual charge-pump mode
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