Datasheet

TPS6734I
FIXED 12-V 120-mA BOOST-CONVERTER SUPPLY
SLVS127A – AUGUST 1995 – REVISED JANUARY 1999
10
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
APPLICATION INFORMATION
continuous mode
When the converter is delivering heavy loads from low voltage sources, it operates in continuous mode. As
shown in Figure 9, the inductor current does not drop to zero and the ringing is gone from the OUT voltage
waveform.
0
0246810
Voltage at Out – V
5
15
CONTINUOUS MODE
20
12 14 16 18
10
1
0.5
0
I– Inductor Current – A
t – Time –µs
V
I
= 5 V
V
O
= 12 V
I
L
= 150 mA
Figure 9
pulse-skipping mode
At very light load currents, the TPS6734 cannot generate drive pulses sufficiently narrow to maintain regulation
and operate at 170 kHz. Under these circumstances, the converter operates in a pulse-skipping mode, in which
cycles are skipped. In pulse-skipping mode, the waveforms are irregular and the output ripple contains a
low-frequency component that may exceed 50 mV peak-to-peak.