参数资料
型号: L6728H
厂商: STMICROELECTRONICS
元件分类: 稳压器
英文描述: SWITCHING CONTROLLER, 330 kHz SWITCHING FREQ-MAX, PDSO10
封装: 3 X 3 MM, ROHS COMPLIANT, DFN-10
文件页数: 7/32页
文件大小: 1213K
代理商: L6728H
Obsolete
Product(s)
- Obsolete
Product(s)
L6728H
Application details
Doc ID 15725 Rev 1
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 VIN
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 VOUT. This function has a double pole at frequency FLC depending on the L-COUT
resonance and a zero at FESR depending on the output capacitor ESR. The DC gain of the
modulator is simply the input voltage VIN divided by the peak-to-peak oscillator voltage
ΔV
OSC.
Figure 5.
PWM control loop
The compensation network closes the loop joining VOUT and EA output with transfer
function ideally equal to -Z
F/ZFB.
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 (F0dB) can be fixed choosing the right RF/RFB ratio, however, for
stability, it should not exceed FSW/2π. To achieve a good phase margin, the control loop gain
has to cross 0 dB axis with -20 dB/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
ΔV
OSC
+
_
V
OUT
V
REF
ZF
Z
FB
PWM
COMPARATOR
ERROR
AMPLIFIER
R
S
相关PDF资料
PDF描述
L6728 1.5 A SWITCHING CONTROLLER, 330 kHz SWITCHING FREQ-MAX, DSO10
L6728TR 1.5 A SWITCHING CONTROLLER, 330 kHz SWITCHING FREQ-MAX, DSO10
L6731BTR 20 A SWITCHING CONTROLLER, 500 kHz SWITCHING FREQ-MAX, PDSO16
L6731B 20 A SWITCHING CONTROLLER, 500 kHz SWITCHING FREQ-MAX, PDSO16
L6731D 20 A SWITCHING CONTROLLER, 500 kHz SWITCHING FREQ-MAX, PDSO16
相关代理商/技术参数
参数描述
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L6728TR 功能描述:DC/DC 开关控制器 Sngl phase PWM controller RoHS:否 制造商:Texas Instruments 输入电压:6 V to 100 V 开关频率: 输出电压:1.215 V to 80 V 输出电流:3.5 A 输出端数量:1 最大工作温度:+ 125 C 安装风格: 封装 / 箱体:CPAK
L6730 功能描述:DC/DC 开关控制器 Adjustable Step Down Controller RoHS:否 制造商:Texas Instruments 输入电压:6 V to 100 V 开关频率: 输出电压:1.215 V to 80 V 输出电流:3.5 A 输出端数量:1 最大工作温度:+ 125 C 安装风格: 封装 / 箱体:CPAK
L6730_09 制造商:STMICROELECTRONICS 制造商全称:STMicroelectronics 功能描述:Adjustable step-down controller with synchronous rectification
L6730B 功能描述:DC/DC 开关控制器 Adjustable Step Down Controller RoHS:否 制造商:Texas Instruments 输入电压:6 V to 100 V 开关频率: 输出电压:1.215 V to 80 V 输出电流:3.5 A 输出端数量:1 最大工作温度:+ 125 C 安装风格: 封装 / 箱体:CPAK