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Vg=28 Vo=15 Ro=3
$ i! A1 Z. y; a. zH=5/15 分壓
% |1 J6 u( \* d1 i( C: GVref=5
# M. E4 I2 z# A% VRM
2 s) c4 f1 Q- o8 Rs = tf('s');
" j9 j8 F6 E: k2 s3 K% Input voltage Vin
& m7 Z! {% w7 J; P$ _* `Vin=28 C6 {" ?' b( c
% Output voltage Vo
\# N# o8 T4 O4 c/ O+ VVo=153 A% T8 r2 e4 p( F
% LOAD R
: g( ^! `7 W# k4 ~) }RL=33 P% z7 ?5 e& J2 i3 \
% PWM operating frequency Fsw8 E5 ^, u7 y# ^7 h7 ^$ Y" S
Fsw=100e30 E7 d6 T: S& m; a
% PWM operating period Ts
, P6 n" ^* d$ A9 zTs=1/Fsw/ q) K d. u: u# y, [
% duty cycle D/ f/ M8 p5 r) B* u# u
D=Vo/Vin
0 s- v8 ~) d7 h" u% Inductance L" l w4 w, v0 E: i* i
L=50e-6; H" e. B b8 r* G; C
% Output capacitance* `% R+ E' d% r4 D* h, |
Co=500e-60 `( ]8 [5 c( n2 L
%power stage Gvd
# W: p, v* B: V%Gvd=(Vin*((s*Co*RL*rc)+RL))/((s^2*L*Co*(RL+rc))+(s*(L+(Co*rc*rL)+Co*RL*(rc+rL)))+RL+rL)8 D j- o: P$ p" o
Gvd=(Vin*RL)/((s^2*L*Co*RL)+s*L+RL)8 C) ~! F) q8 z: k! a9 t( O
figure(1)
/ _; X# z4 p& Fmargin(Gvd)
9 J/ o7 _* j1 } {$ uF0=1/(2*pi*sqrt(L*Co))
' z U$ n* j* U# H, Z/ x: O%Fesr=1/(2*pi*Co*rc)
; n' G0 s+ z% A/ d6 zFc=Fsw/208 ^! N; y) ]6 l! T! T2 ~: @. g
% 分壓比* o' f) }0 o/ U. Z0 S- [
H=1/3
/ [5 v" e1 W/ n4 F% PWM Vm7 B$ O, Q' @: x& D- n9 P' {
Vm=4
% V; X ?. J! N4 g& b5 z% uncompensation loop gain Tu0
) p4 P6 e" q( GTu0=H*Vin/Vm
1 P( s, q" D' H9 y9 O$ g% 補償zero Fz
6 p6 `7 [8 [# l& JFz=Fc*sqrt((1-sin (52*(pi/180)))/(1+sin (52*(pi/180))))
# J" i6 }! j1 K0 N2 p% 補償pole Fp 7 u* O6 A6 N8 X% `
Fp=Fc*sqrt((1+sin (52*(pi/180)))/(1-sin (52*(pi/180))))
) |9 ~( `+ K7 F3 {8 bWz=2*pi*Fz
. W9 ^6 N" a' v# M( N7 F! XR1=2e3$ G6 ~+ H ?# A ]
C1=1/(R1*Wz)" N% L( u: a- x, x1 k0 D
Wp=2*pi*Fp
/ ~' ]& S4 u1 w, R3 C; N. K0 _# bR3=R1/(Wp*R1*C1-1), f7 t' c" M+ n6 v: V1 S0 h0 v
% compensation gain Gc0
; ~( f3 G- h# kGc0=(((Fc/F0)^2)/Tu0)*sqrt(Fz/Fp), R5 l% ^: C1 q U4 t
R2=Gc0*(R1+R3)
% k3 v* ^6 ]0 w g1 V* x8 y+ D% OPA gain:A;OPA open loop gain:A0 ; dominant pole ; compensator close feedback gain:Gcl 3 ~' p% i: i; ?
A0=1
% R3 Z! I0 M: ?, i. w# ]p=10e3*2*pi
7 G' M3 F# C5 k2 d2 V9 ?6 X5 LA=A0*p/(s+p)8 {6 H0 V' O- G7 x
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)))
) g( `, o6 H- gfigure(2)+ O) t8 M& ?1 d+ Q( u/ v
bode(Gc,A)
1 w; G( ~' ~ R6 e8 ]& J% total loop gain T' s7 V# f+ M1 ^9 m9 s4 z+ I6 [
T=Tu0*Gc0*(1+s/Wz)*RL/((1+s/Wp)*((s^2*L*Co*RL)+s*L+RL))
2 S) n9 F/ }+ J% O$ @2 e3 n" v% total colse loop gain Gcl
! o) o- |$ ?7 w) e- o- z0 s9 zGcl=(Gc*(1/Vm)*Gvd)/(1+Gc*(1/Vm)*Gvd*H)2 `8 }0 J+ v* o% ?
figure(3)
' M4 {9 S5 ]* bbode(Gvd,Gcl,Gc,A,T) |
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