參數(shù)資料
型號: L6728
廠商: 意法半導(dǎo)體
英文描述: Single phase PWM controller with PowerGOOD
中文描述: 單相PWM控制器與電源良好
文件頁數(shù): 15/32頁
文件大?。?/td> 942K
代理商: L6728
L6728
Application details
15/32
10
Application details
10.1
Compensation network
The control loop showed in
Figure 5
is a voltage mode control loop. The output voltage is
regulated to the internal reference (when present, offset resistor between FB node and GND
can be neglected in control loop calculation).
Error Amplifier output is compared to oscillator saw-tooth waveform to provide PWM signal
to the driver section. PWM signal is then transferred to the switching node with V
IN
amplitude. This waveform is filtered by the output filter.
The converter transfer function is the small signal transfer function between the output of the
EA and V
OUT
. This function has a double pole at frequency F
LC
depending on the L-C
OUT
resonance and a zero at F
ESR
depending on the output capacitor ESR. The DC Gain of the
modulator is simply the input voltage V
IN
divided by the peak-to-peak oscillator voltage
V
OSC
.
Figure 5.
PWM control loop
The compensation network closes the loop joining V
OUT
and EA output with transfer
function ideally equal to -Z
F
/
Z
FB
.
Compensation goal is to close the control loop assuring high DC regulation accuracy, good
dynamic performances and stability. To achieve this, the overall loop needs high DC gain,
high bandwidth and good phase margin.
High DC gain is achieved giving an integrator shape to compensation network transfer
function. Loop bandwidth (F
0dB
) can be fixed choosing the right R
F
/R
FB
ratio, however, for
stability, it should not exceed F
SW
/2
π
. To achieve a good phase margin, the control loop gain
has to cross 0dB axis with -20dB/decade slope.
As an example,
Figure 6
shows an asymptotic bode plot of a type III compensation.
L
R
C
OUT
ESR
R
F
C
F
C
P
R
FB
C
S
OSC
V
IN
V
OSC
+
+
_
_
V
OUT
V
REF
Z
F
Z
FB
PWM
COMPARATOR
ERROR
AMPLIFIER
R
S
相關(guān)PDF資料
PDF描述
L6728TR Single phase PWM controller with PowerGOOD
L6731B Transistor; Type: Amplifiers/Bipolar; VCEO (V): 25; Ic (A): 1; Pc (W): 0.8; hFE: 85 to 330; VCE (sat) (V) max: 0.5; Package: TO-92Mod
L6731BTR Transistor; Type: Amplifiers/Bipolar; VCEO (V): -25; Ic (A): -1; Pc (W): 0.8; hFE: 85 to 330; VCE (sat) (V) max: -0.5; Package: TO-92Mod
L6732 Adjustable step-down controller with synchronous rectification
L6732TR Adjustable step-down controller with synchronous rectification
相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
L6728_0706 制造商:STMICROELECTRONICS 制造商全稱:STMicroelectronics 功能描述:Single phase PWM controller with Power Good
L6728A 功能描述:電壓模式 PWM 控制器 Hi-Freq. singl-phase PWM controller w/Po RoHS:否 制造商:Texas Instruments 輸出端數(shù)量:1 拓?fù)浣Y(jié)構(gòu):Buck 輸出電壓:34 V 輸出電流: 開關(guān)頻率: 工作電源電壓:4.5 V to 5.5 V 電源電流:600 uA 最大工作溫度:+ 125 C 最小工作溫度:- 40 C 封裝 / 箱體:WSON-8 封裝:Reel
L6728AH 功能描述:軟開關(guān) PWM 控制器 Sgl Output 600 KHz DFPN-10 RoHS:否 制造商:Fairchild Semiconductor 輸出端數(shù)量: 輸出電流: 開關(guān)頻率: 工作電源電壓:30 V 電源電流: 最大工作溫度:+ 105 C 最小工作溫度:- 40 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:SOIC-8 封裝:Reel
L6728AHTR 功能描述:電流型 PWM 控制器 HIGH FREQ PWM CNTRL W/PO RoHS:否 制造商:Texas Instruments 開關(guān)頻率:27 KHz 上升時間: 下降時間: 工作電源電壓:6 V to 15 V 工作電源電流:1.5 mA 輸出端數(shù)量:1 最大工作溫度:+ 105 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:TSSOP-14
L6728ATR 功能描述:電壓模式 PWM 控制器 HIGH FREQ SINGLE PHASE PWM CNTRL RoHS:否 制造商:Texas Instruments 輸出端數(shù)量:1 拓?fù)浣Y(jié)構(gòu):Buck 輸出電壓:34 V 輸出電流: 開關(guān)頻率: 工作電源電壓:4.5 V to 5.5 V 電源電流:600 uA 最大工作溫度:+ 125 C 最小工作溫度:- 40 C 封裝 / 箱體:WSON-8 封裝:Reel