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续流用的,开关和电感同时作用,
6 B9 a+ J9 V6 M6 P% s1 w6 `With the PFET on, the input supply charges COUT and
7 @. e+ q0 y: Tsupplies current to the load via the series path through the9 S8 |3 C; c2 G8 I$ z9 S
PFET and the inductor. Current through the Inductor ramps
" d7 N* {7 b' Y: x. T( f; d8 o8 Jup linearly and the output voltage increases. As the FB voltage
) {3 g7 F5 f2 ?/ A. f! S( I# greaches the upper threshold, which is the internal reference
& Y6 ^. B- _% g; S9 w2 h9 ^3 K8 U8 mvoltage plus 10mV, the output of the comparator2 ?4 g3 @) e9 J* I* G
changes from low to high, and the PGATE responds by turning
7 r/ @( C$ B! [! X7 N1 g) gthe PFET off. As the PFET turns off, the inductor voltage7 V% j9 s4 V# Y8 ?( _0 _
reverses, the catch diode turns on, and the current through
6 X- y4 ?+ L0 l- R1 _% A% w0 {' athe inductor ramps down. Then, as the output voltage reaches
: Q" o# v3 E" U) wthe internal reference voltage again, the next cycle starts |
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