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CM6806AIR 参数 Datasheet PDF下载

CM6806AIR图片预览
型号: CM6806AIR
PDF下载: 下载PDF文件 查看货源
内容描述: 10 -PIN绿色模式PFC / PWM组合控制器的高密度电源适配器 [10-PIN Green-Mode PFC/PWM Combo CONTROLLER for High Density AC Adapter]
分类和应用: 功率因数校正控制器
文件页数/大小: 16 页 / 391 K
品牌: CHAMP [ CHAMPION MICROELECTRONIC CORP. ]
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CM6805(A;B)/CM6806A  
10-PIN Green-Mode PFC/PWM Combo CONTROLLER for High Density AC Adapter  
One of the advantages of this control technique is that it  
ZCV: Compensation Net Work for the Voltage Loop  
GMv: Transconductance of VEAO  
PIN: Average PFC Input Power  
VOUTDC: PFC Boost Output Voltage; typical designed value is  
380V.  
required only one system clock. Switch 1(SW1) turns OFF  
and switch 2 (SW2) turns ON at the same instant to  
minimize the momentary “no-load” period, thus lowering  
ripple voltage generated by the switching action. With such  
synchronized switching, the ripple voltage of the first stage  
is reduced. Calculation and evaluation have shown that the  
120Hz component of the PFC’s output ripple voltage can be  
reduced by as much as 30% using this method,  
substantially reducing dissipation in the high-voltage PFC  
capacitor.  
CDC: PFC Boost Output Capacitor  
ΔVEAO: This is the necessary change of the VEAO to deliver  
the designed average input power. The average value is  
6V-3V=3V since when the input line voltage increases, the  
delta VEAO will be reduced to deliver the same to the output.  
To over compensate, we choose the delta VEAO is 3V.  
Typical Applications  
PFC Section:  
Internal Voltage Ramp  
The internal ramp current source is programmed by way of  
VEAO pin voltage. When VEAO increases the ramp current  
source is also increase. This current source is used to  
develop the internal ramp by charging the internal 30pF +12/  
-10% capacitor. The frequency of the internal programming  
ramp is set internally to 67kHz.  
PFC Voltage Loop Error Amp, VEAO  
The ML4803 utilizes an one pin voltage error amplifier in  
the PFC section (VEAO). In the CM6805A/CM6806A, it is  
using the slew rate enhanced transconductance amplifier,  
which is the same as error amplifier in the CM6800. The  
unique transconductance profile can speed up the  
conventional transient response by 10 times. The internal  
reference of the VEAO is 2.5V. The input of the VEAO is  
VFB pin.  
Design PFC ISENSE Filtering  
ISENSE Filter, the RC filter between Rs and ISENSE:  
There are 2 purposes to add a filter at ISENSE pin:  
1.) Protection: During start up or inrush current  
conditions, it will have a large voltage cross Rs,  
which is the sensing resistor of the PFC boost  
converter. It requires the ISENSE Filter to attenuate  
the energy.  
PFC Voltage Loop Compensation  
The voltage-loop bandwidth must be set to less than 120Hz  
to limit the amount of line current harmonic distortion. A  
typical crossover frequency is 30Hz.  
The Voltage Loop Gain (S)  
2.) Reduce L, the Boost Inductor: The ISENSE Filter  
also can reduce the Boost Inductor value since the  
ISENSE Filter behaves like an integrator before  
going ISENSE which is the input of the current error  
amplifier, IEAO.  
ΔVOUT  
ΔVEAO ΔVOUT  
ΔVFB ΔVEAO  
=
*
*
ΔVFB  
P
IN *2.5V  
*GM *ZCV  
V
V
OUTDC2 *ΔVEAO *S*CDC  
2006/10/11 Rev1.0  
Champion Microelectronic Corporation  
Page 10