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续流用的,开关和电感同时作用,
; E/ z# U# O4 DWith the PFET on, the input supply charges COUT and
: y5 U8 ?1 t5 z3 H; X+ i! ksupplies current to the load via the series path through the
2 y/ x6 c/ M& j5 Q0 a ], e. hPFET and the inductor. Current through the Inductor ramps* C3 K4 i5 Y- _
up linearly and the output voltage increases. As the FB voltage7 {8 B) C) {# w& T F: y: I
reaches the upper threshold, which is the internal reference
6 z( W. u1 w. f! g: \9 c1 N P% Rvoltage plus 10mV, the output of the comparator
0 _. K y5 f4 R$ Ichanges from low to high, and the PGATE responds by turning( n0 o* k% [& h! \+ S
the PFET off. As the PFET turns off, the inductor voltage
4 W: [6 G# [1 c. e/ Zreverses, the catch diode turns on, and the current through
: v9 r1 Q1 z0 a* F3 Vthe inductor ramps down. Then, as the output voltage reaches
5 `; [$ I% n. E1 Q% P _# i* H, `the internal reference voltage again, the next cycle starts |
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