参数资料
型号: NCP1650DR2
厂商: ON Semiconductor
文件页数: 28/31页
文件大小: 0K
描述: IC CTRLR PWR FACTOR PWM 16SOIC
标准包装: 1
模式: 连续导电(CCM),间歇导电(DCM)
频率 - 开关: 100kHz
电源电压: 10 V ~ 20 V
工作温度: -40°C ~ 125°C
安装类型: 表面贴装
封装/外壳: 16-SOIC(0.154",3.90mm 宽)
供应商设备封装: 16-SOIC
包装: 标准包装
其它名称: NCP1650DR2OSDKR
NCP1650
in the introduction to this analysis, this is not analyzed
separately.
The equation for the gain is good for frequencies below
the pole. There is a single pole due to the output filter. Since
the NCP1650 is a current mode converter, the inductor is not
part of the output pole as can be seen in that equation.
Plot the sum of these three values. Figure 43 shows a gain
of 35.5 dB until the pole of the output filter is reached at
0.3 Hz. After that, the gain is reduced at a rate of
20 dB/decade.
40
Calculating the Loop Gain
At this point in the design process, all of the parameters
involved in this calculation have been determined with the
exception of the pole--zero pair on the output of the voltage
error amplifier.
All equations give gains in absolute numbers. It is
necessary to convert these to the decibel format using the
following formula:
30
20
10
0
--10
--20
LOOP GAIN
WITHOUT
ERROR AMP
A =
= .0099
A(dB) = 20 Log10 (A)
For example, the voltage divider would be:
5.6 k
560 k + 5.6 k
--30
--40
0.01
0.1
1 10
FREQUENCY (Hz)
100
1000
C =
= 85 m F
A(dB) = 20 Log10 .0099 = ? 40 dB
The gain of the loop will vary as the input voltage changes.
It is recommended that the compensation for the voltage
error amplifier be calculated under high line, full load
conditions. This should be the greatest bandwidth that the
unit will see.
By necessity, the unity gain (OdB) loop bandwidth for a
PFC unit, must be less than the line frequency. If the
bandwidth approaches or exceeds the line frequency, the
voltage error amplifier signal will have frequency
components in its output that are greater than the line
frequency. These components will cause distortion in the
output of the reference amplifier, which is used to shape the
current waveform. This in turn will cause distortion in the
current and reduce the power factor.
Typically the maximum bandwidth for a 60 Hz PFC
converter is 10 Hz, and slightly less for a 50 Hz system. This
can be adjusted to meet the particular requirements of a
system. The unity gain bandwidth is determined by the
frequency at which the loop gain passes through the 0 dB
level.
Figure 43. Open Loop Gain Less Error Amp
A typical error amplifier bode plot is shown in Figure 44.
The zero is used to offset the pole of the output filter. The
output filter pole will typically be lower than the unity gain
loop bandwidth, so the zero will be necessary.
This plot shows a forward gain of 7.0 dB at 10 Hz. To
compensate for this the error amplifier should have a gain of
–7.0 dB (0.45) at 10 Hz, and a zero at 0.4 Hz. The gain at
10 Hz is determined by the resistor since it is well past the
zero. The resistor can be calculated by the equation:
R7 = Av ∕ Gm = .45 ∕ .0001 = 4.5 k Ω
4.7 kW is the closest standard value. Using this, the
capacitor can be calculated based on the zero frequency of
0.4 Hz. This would give a value for C 7 of:
1
2 ? π ? 4.7 k ? 0.4 Hz
Using these values (4.7 k Ω and 86 m F), the open loop gain
plot would be:
80
For stability purposes, the gain should pass through 0 dB
with a slope of –20 dB/decade for approximately one decade
on either side of the unity gain frequency. This assures a
phase margin of greater than 45 ? .
The gain can be calculated graphically using the equations
of Figure 43 as follows:
Divider: Calculate V’/Vo in dB, this value is constant so
it will not change with frequency.
Reference Signal: Calculate V ref /V e/a using the peak level
of the AC input signal at high line that will be seen on pin 5.
Convert this to dB. This is also a constant value.
60
40
20
0
--20
VOLTAGE
LOOP BODE
PLOT
Modulator and Output Stage: Calculate the gain in dB for
DVo/DVref. Calculate the pole frequency. The gain will be
constant for all frequencies less than f p . Starting at the pole
frequency, this gain will drop off at a rate of 20 dB/decade.
--40
0.01 0.1 1 10 100
FREQUENCY (Hz)
Figure 44. Open Loop Gain of Voltage Loop
1000
http://onsemi.com
28
相关PDF资料
PDF描述
KA78RM33RTM IC REG LDO 3.3V .5A DPAK
RJZ-2412S/H CONV DC/DC 2W 24VIN 12VOUT
VE-J0Y-IZ CONVERTER MOD DC/DC 3.3V 16.5W
HSC26DRYI-S93 CONN EDGECARD 52POS DIP .100 SLD
NCP1601AP IC CTRLR PFC FREQ DCM/CRM 8DIP
相关代理商/技术参数
参数描述
NCP1650DR2G 功能描述:功率因数校正 IC Fixed Frequency PFC PWM RoHS:否 制造商:Fairchild Semiconductor 开关频率:300 KHz 最大功率耗散: 最大工作温度:+ 125 C 安装风格:SMD/SMT 封装 / 箱体:SOIC-8 封装:Reel
NCP1650EVB 功能描述:电源管理IC开发工具 EVALUATION BOARD RoHS:否 制造商:Maxim Integrated 产品:Evaluation Kits 类型:Battery Management 工具用于评估:MAX17710GB 输入电压: 输出电压:1.8 V
NCP1651DR2 功能描述:功率因数校正 IC Single Stage PFC RoHS:否 制造商:Fairchild Semiconductor 开关频率:300 KHz 最大功率耗散: 最大工作温度:+ 125 C 安装风格:SMD/SMT 封装 / 箱体:SOIC-8 封装:Reel
NCP1651DR2G 功能描述:功率因数校正 IC Single Stage PFC RoHS:否 制造商:Fairchild Semiconductor 开关频率:300 KHz 最大功率耗散: 最大工作温度:+ 125 C 安装风格:SMD/SMT 封装 / 箱体:SOIC-8 封装:Reel
NCP1652ADR2G 功能描述:功率因数校正 IC ANA PFC CONTROLLER RoHS:否 制造商:Fairchild Semiconductor 开关频率:300 KHz 最大功率耗散: 最大工作温度:+ 125 C 安装风格:SMD/SMT 封装 / 箱体:SOIC-8 封装:Reel