恒定导通时间电流模式控制buck电路小信号分析

过u逼题

---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------满y Do路釐r 满y Do路釐r

满y Do路釐r 恶描获 提得获 度00获 D点 度得获 得感获 感得获 描0获 补度言

综难量l釐y D釐s逼r难过难高g 环u高逼t难o高 补恶言

获s高获s高

离T点恶方度得补得言 电获难高模感方获如获o模恶实恶获如To高模0实得描μs实fs模得抑0题hz 离s模恶实度u电实点o模得型度抑0u环实 综逼o模是展得 mΩ实 ()*()()*(1)*()*()s f Ton L i f fs Vin Gic f

e Vc

f sf Lf s f −=

=− 度 *Vo sf Ri Lf

= fs

补得言

()2***s f

j f

π=如 系路量釐 (

)*2

2

()*1()()11*11s f T o n

s f T o n e s f s f Q ωω−=−

++

得

2

1Q π

=

1Ton

π

ω=

()*()*(1()**)

()*(1)**()*()1()*()*s f Ton Vo f fs Vin Rl s f Rco Co Gvc f e Vc f sf Lf s f s f Rl Rco Co

−+=

=−++ 恶

22

11*(1()**)

()*()()1()*()*11*11Rl s f Rco Co Gvc f s f s f Ri

s f Rl Rco Co Q ωω+=

++++ 感

得

1*1()*

2Ton Ri k f Ls =

1*2()*2Ton Ri

k f Ls

=− 题得(f噪如

22()(1()**)1

1()**

2()*2()()()()*(1****11*111()*

*21Vo f Rl s f Rco Co Gvc f k f Rl k f s f s f Vc f Ri Rl Co Ro Rco Co Ri Ri Q s f Rl k Ri

ωω+=

=−−++

+−

题得(f噪 ()1()**)

2()*()1()**Vo f Rl s f Rco Co Gvc f Vc f Ri

s f Rl Co +==+ 抑

度 获s高 获s高 获th

离T点恶方度得 量路t路sh釐釐t 获th 感路 获s高

获th

获r高g

1.2(

,)(0.1440.022)*

RNG RNG Vth V

Vsn V Vth V V V

−=−

((,))

()

RNG d Vsn V Vth Gmc d Vth =

1

(0.1440.022)*

0.266RNG Gmc V V V

=−=

恶 获s高 获th

感路 益th 感过 益th

Gv逼得 f 型Gm逼如

1

704

fc fs kHz =

= Typ釐益益 180deg 60deg 90deg arg(2()*)31deg Gvc fc Gmc θ=−++−= 知

tan(45deg 1.7662K θ=+= 39.6fc

fcomz kHz K

== *123.6fcomp K fc kHz ==

|()*|B R Rcom Gvc fc Gmc =

112***CC fcomp Rcom π= 122***CC fcomz Rcom

π=

h

()1()**()T f Gvc f Gmc Gcomp f = 1()2()**()T f Gvc f Gmc Gcomp f =

抑

描

提抑实恶题电z实 提度

果

[1].Greg Dittmer. "Direct Efficient DC/DC Conversion of 100V Inputs for Telecom/Automotive Supplies". Linear Technology. Design Note 398.

[2] Linear Technology."60V Current Mode Synchronous Switching Regulator controller".

LTC3812 datasheet.

[3]. Analog Devices." Synchronout Buck Controller with Constant on-time and Valley Current Mode.ADP1874/ADP1875.

[4]. Jian Li. "Current-Mode Control: Modeling and its Digital Application". Doctor Disseration. April 2009

[5] John Seago."Opti-Loop Architecture Reduces Output Capacitance and Improves Transient Response". Linear Technology . Application Note 76. May 1999