参数资料
型号: PM6670STR
厂商: STMICROELECTRONICS
元件分类: 稳压器
英文描述: 3 A SWITCHING CONTROLLER, QCC24
封装: 4 X 4 MM, LEAD FREE, VFQFPN-24
文件页数: 18/54页
文件大小: 742K
代理商: PM6670STR
PM6670S
Device description
Doc ID 14432 Rev 4
25/54
The design of the external feedback network depends on the output voltage ripple. If the
ripple is higher than approximately 20 mV, the correct CINT capacitor is usually enough to
keep the loop stable. The stability of the system depends firstly on the output capacitor zero
frequency.
The following condition must be satisfied:
Equation 6
where k is a fixed design parameter (k > 3). It determines the minimum integrator capacitor
value:
Equation 7
where gm = 50
μs is the integrator trans conductance.
In order to ensure stability it must be also verified that:
Equation 8
If the ripple on the COMP pin is greater than the integrator 150 mV, the auxiliary capacitor
CFILT can be added. If q is the desired attenuation factor of the output ripple, CFILT is given
by:
Equation 9
In order to reduce the noise on the COMP pin, it is possible to add a resistor RINT that,
together with CINT and CFILT, becomes a low pass filter. The cutoff frequency fCUT must be
much greater (10 or more times) than the switching frequency:
Equation 10
If the ripple is very small (lower than approximately 20 mV), a different compensation
network, called “Virtual-ESR” network, is needed. This additional circuit generates a
triangular ripple that is added to the output voltage ripple at the input of the integrator. The
complete control scheme is shown in Figure 32.
ESR
C
2
k
f
k
f
out
Zout
SW
π
=
>
Vout
Vr
f
k
f
2
g
C
Zout
SW
m
INT
π
>
OUT
Zout
m
INT
V
Vr
f
2
g
C
π
>
q
)
q
1
(
C
INT
FILT
=
FILT
INT
FILT
INT
CUT
INT
C
f
2
1
R
+
π
=
相关PDF资料
PDF描述
PM6670S 3 A SWITCHING CONTROLLER, QCC24
PM6670TR 1.4 A SWITCHING CONTROLLER, QCC24
PM6670ATR 1.4 A SWITCHING CONTROLLER, QCC24
PM6670 1.4 A SWITCHING CONTROLLER, QCC24
PM6675ASTR 3 A SWITCHING CONTROLLER, QCC24
相关代理商/技术参数
参数描述
PM6670TR 功能描述:直流/直流开关调节器 Complete DDR2/3 Mem Pwr supply controllr RoHS:否 制造商:International Rectifier 最大输入电压:21 V 开关频率:1.5 MHz 输出电压:0.5 V to 0.86 V 输出电流:4 A 输出端数量: 最大工作温度: 安装风格:SMD/SMT 封装 / 箱体:PQFN 4 x 5
PM6675 制造商:STMicroelectronics 功能描述: 制造商:STMicroelectronics 功能描述:LDO CNTRLR STDN 0.6V TO 3.3V/1.5V 24PIN VFQFPN - Rail/Tube
PM6675AS 功能描述:DC/DC 开关控制器 DDR 2/3 Memory Pwr Cntrl 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
PM6675ASTR 功能描述:低压差控制器 - LDO Complete DDR2/3 Mem Pwr supply controllr RoHS:否 制造商:Micrel 最大输入电压:5.5 V 输出电压:Adjustable 输出电流:10 mA 负载调节: 输出类型:Adjustable, Fixed 输出端数量:1 最大工作温度:+ 125 C 安装风格:SMD/SMT 封装 / 箱体:SOT-23-6
PM6675ATR 功能描述:低压差控制器 - LDO High eff SD CNRL RoHS:否 制造商:Micrel 最大输入电压:5.5 V 输出电压:Adjustable 输出电流:10 mA 负载调节: 输出类型:Adjustable, Fixed 输出端数量:1 最大工作温度:+ 125 C 安装风格:SMD/SMT 封装 / 箱体:SOT-23-6