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Vg=28 Vo=15 Ro=35 u3 J* V; ?0 }$ q
H=5/15 分壓: g n6 D0 ]! i% u9 p2 F
Vref=5
/ d: p6 V2 ~( a+ }# h2 `7 N% VRM
( U, B: ^( s& Q( ]$ ys = tf('s');3 ]4 A- z# s9 B
% Input voltage Vin
. Y% ^- w+ `. f1 @0 wVin=28/ N- n' p; Z q4 ?: m
% Output voltage Vo
2 h# N6 c s- \- o5 D/ |. ^( lVo=15
2 d5 F) }9 u1 C4 X, v: z% LOAD R0 G: [0 W. G/ K5 p
RL=3
, c$ Z; u& F8 F% PWM operating frequency Fsw
5 ?$ ]0 I7 ]3 b" S) s, r3 ^3 ~Fsw=100e3
W( k$ N# f: J: S% PWM operating period Ts: Q3 k- d% u" L8 u
Ts=1/Fsw! Y+ G$ S/ P$ `& r
% duty cycle D
9 e0 H. I" l9 Q" I/ LD=Vo/Vin. X( ]9 k' v5 q1 \% T
% Inductance L$ e9 V& m7 D7 i: |3 C
L=50e-6
: d; b* U1 U0 `/ B% Output capacitance& I0 G: \& N' }- r
Co=500e-63 j7 U. y0 c+ X8 r
%power stage Gvd
' z4 Q. m+ n# u0 P% e%Gvd=(Vin*((s*Co*RL*rc)+RL))/((s^2*L*Co*(RL+rc))+(s*(L+(Co*rc*rL)+Co*RL*(rc+rL)))+RL+rL)
+ ]) A% ]# j l. K+ |+ mGvd=(Vin*RL)/((s^2*L*Co*RL)+s*L+RL)# V/ X! o; `; J; ]; m8 |6 `
figure(1)- r4 S6 y+ {$ V ?7 A- U* `' R0 ^' E
margin(Gvd)! j" V# `3 b# \& q
F0=1/(2*pi*sqrt(L*Co))
1 ^! Q4 R7 Z* T+ s' h2 B%Fesr=1/(2*pi*Co*rc)
, B) H" i- Z8 ZFc=Fsw/20. P* t; K7 C. _% R8 V0 G
% 分壓比4 g8 ?9 }9 o$ x" S1 _
H=1/3) F# n8 X! n9 w+ _ G$ m0 h
% PWM Vm
) o6 C8 Z4 b1 h: ^Vm=4" d; @6 g% O* R( L3 t: C
% uncompensation loop gain Tu06 `$ H W. j. L8 y6 v3 G
Tu0=H*Vin/Vm
! t# _) d+ b# V: s% A& }" R% 補償zero Fz 7 m3 R; v7 K4 N; M9 [- K4 _# Q
Fz=Fc*sqrt((1-sin (52*(pi/180)))/(1+sin (52*(pi/180))))" R% d4 ]1 b9 {* R4 U7 Q- H6 [
% 補償pole Fp + v% L Q% J3 G3 }
Fp=Fc*sqrt((1+sin (52*(pi/180)))/(1-sin (52*(pi/180))))9 w+ s! ?+ T. K2 w ]
Wz=2*pi*Fz
3 x1 X/ f3 ^1 T: h* w2 U" \R1=2e3
9 o! w6 Z# K' l! f8 r4 ~C1=1/(R1*Wz)
|$ R5 K; T" |! i, r: u1 | xWp=2*pi*Fp
% G3 ]( F4 z1 x4 ?3 h! j- z/ yR3=R1/(Wp*R1*C1-1)# M, B- J/ Z! x
% compensation gain Gc0
( n# N. p+ F* L+ l( xGc0=(((Fc/F0)^2)/Tu0)*sqrt(Fz/Fp)
: a8 a7 q% @7 `9 L4 b0 n0 zR2=Gc0*(R1+R3)
8 \5 ]5 B' ~6 S) X: [9 ^) v+ u% OPA gain:A;OPA open loop gain:A0 ; dominant pole ; compensator close feedback gain:Gcl . E- ^# n @* O/ w! @3 P' T! k+ n
A0=19 A8 k( P8 e0 _
p=10e3*2*pi3 |2 C8 r6 H" Q; _+ L& B# u: B; C
A=A0*p/(s+p)$ G5 n+ L. |2 e* M) |( i
Gc=(A0*p*R2+s*A0*p*R1*R2*C1)/(s^2*(R1*R2*C1+C1*R1*R3)+s*(A0*p*R1*R3*C1+p*R1*R3*C1+p*R1*R2*C1+R1+R2+R3)+(A0*p*R1+A0*p*R3+p*(R1+R3+R2)))
! r0 R8 b1 q$ j' ]% `* W5 Z e! r. Rfigure(2)/ i$ N i+ _6 A, Z6 r/ e0 E
bode(Gc,A)1 B% D+ W" } v5 G5 b" } {, _* r; _
% total loop gain T
% k1 k h d3 U8 QT=Tu0*Gc0*(1+s/Wz)*RL/((1+s/Wp)*((s^2*L*Co*RL)+s*L+RL))
4 z0 F8 T" Z* K& n1 \% total colse loop gain Gcl
5 H- }# x6 t! C! g% ^/ iGcl=(Gc*(1/Vm)*Gvd)/(1+Gc*(1/Vm)*Gvd*H)2 {; [+ C: w5 R/ m" w3 {
figure(3)/ ^# y: I# D' g5 e: r
bode(Gvd,Gcl,Gc,A,T) |
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