- 您现在的位置：买卖IC网 > Sheet目录1211 > DM330023 (Microchip Technology)BOARD DEV DSPICDEM MCHV
Hardware
4.1.3
PFC Feedback Circuitry
In a DSC-based PFC, the relevant analog parameters and the control loops need to be
redefined and discretized. This enables changeover from existing hardware to its digital
counterpart easier and more logical.
The PFC is an AC-to-DC converter, which converts the AC input voltage to a DC volt-
age and maintains sinusoidal input current at a high input power factor. In a DSC-based
PFC, three inputs signals are required to implement the current control.
The input rectifier (BR1) converts (shown in Section 4.1.1 “AC Supply Input ” ) the
alternating voltage at power frequency into unidirectional voltage. This rectified voltage
is fed to the chopper circuit to produce a smooth and constant DC output voltage to the
load. The chopper circuit is controlled by the PWM switching pulses generated by the
dsPIC DSC device, based on three measured feedback signals:
?
?
?
?
Rectified input voltage
AC input voltage zero-crossing event
Rectified input current
DC bus voltage
The rectified input voltage is measured in two stages:
? Signal conditioning: R22, R23, R24, C24, and D7 convert and filter the AC input
voltage waveform from 90-265 VAC to 0-3.3 VAC. D7 limit the maximum voltage
to 3.3V. C24 along with R22, R23 form a low-pass filter. The circuit is shown in
Appendix A.
? Amplification: the operational amplifier MCP6024 (U13B) amplifies the condi-
tioned AC input voltage; R45, R46, R47, R48, R49 and R51 set the gain. The
MC6024 also shifts the conditioned AC input voltage to a 1.65V DC level. There-
fore, the voltage applied to the dsPIC DSC ADC channel varies within 0-3.3V. The
offset is controlled by R50, R53, and R54. R39 and C39 filter out the
high-frequency noise.
AC input voltage zero-crossing event is sensed using a voltage divider (R2-R5) and two
opto-couplers (U1 and U2). The circuit is shown in Appendix A.
Rectified input current is measured using the shunt resistor R34 and the operational
amplifier MCP6024 (U13A); R38, R39, R40, R41, R42 and R43 set the gain. R43 shifts
the voltage present at the shunt resistor to a 1.65V DC level. Therefore, the voltage
applied to the dsPIC DSC ADC channel varies within 0-3.3V. The offset is controlled by
R43, R53, and R54. R44 and C37 filter out the high-frequency noise. The circuit is
shown in Appendix A.
DC bus voltage, the DC bus voltage is sensed at the power module stage. Please refer
4.1.4
Power Supplies
The PFC stage board provides the 15 volts power supply required to fire the power
module IGBTs. The 15 volts power supply is built using a low power off-line SMPS pri-
mary switcher. The switching frequency is fixed to 60 kHz, the feedback signal to the
power supply is provided by and opto-coupler. The output voltage is regulated at 15V
with a maximum output current of 0.750 A, the resultant maximum power is 11.25 W.
The input voltage range for this power supply is from 90 VAC to 260 VAC.
The PFC stage board also provides the 3.3 volts to powering-up the dsPIC DSC, the
isolation circuitry, the communication ports, the Starter Kit programmer, etc. It also gen-
erates the 3.3 volts for powering the analog circuits and the analog reference for the
Analog-To-Digital converter.
? 2009 Microchip Technology Inc.
DS70605A-page 31
发布紧急采购，3分钟左右您将得到回复。
相关PDF资料
DMA-MC-XP-N2
IP CORE MCDMA CTLR XPGA ISPXPGA
DN-5002C
N-WAY ETHERNET SWITCH 8-PORT
DN-7006GS
WIRELESS LAN PCI ADAPTER
DN-7020
WIFI FINDER W/DISPLAY WLAN ADAPT
DN-93501-U/BL
CONN JCK RJ45 TOOL FREE CAT5E BK
DN-93501-U/B
CONN JCK RJ45 TOOL FREE CAT5E BU
DN-93501-U/R
CONN JCK RJ45 TOOL FREE CAT5E RD
DN-93501-U/WH
CONN JCK RJ45 TOOL FREE CAT5E WT
相关代理商/技术参数
DM330023
制造商:Microchip Technology Inc 功能描述:dsPICDEM MCHV Development Board
DM330023-2
功能描述:电源管理IC开发工具 dsPICDE MCHV-2
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
DM-330-C
制造商:Greenlee Textron Inc 功能描述:DMM 1000V 10A RMS
DM3312X101R (2500 REEL)
制造商:Laird Technologies Inc 功能描述:IND CHIP BEAD 100OHM 100MHZ 10A - Tape and Reel
DM3312X101R-00
功能描述:FERRITE ULTRA HC 100 OHMS SMT RoHS:否 类别:滤波器 >> 铁氧体磁珠和芯片 系列:- 标准包装:1,000 系列:EMI1812 频率对应阻抗:120 欧姆 @ 100MHz 额定电流:200mA DC 电阻(DCR):最大 400 毫欧 滤波器类型:差模 - 单线 封装/外壳:1812（4532 公制） 安装类型:表面贴装 包装:带卷 (TR) 高度（最大）:0.069"（1.75mm） 尺寸/尺寸:0.177" L x 0.126" W（4.50mm x 3.20mm） 其它名称:Q1712807A
DM3312X101R-10
功能描述:电磁干扰滤波珠子、扼流圈和阵列 100ohms 100MHz
RoHS:否 制造商:AVX 阻抗: 最大直流电流:35 mA 最大直流电阻: 容差: 端接类型:SMD/SMT 电压额定值:25 V 工作温度范围:- 25 C to + 85 C 封装 / 箱体:0603 (1608 metric)
DM-333
制造商:Labfacility Limited 功能描述:SENSOR PT100 THIN FILM 2X10MM CL B 制造商:LABFACILITY 功能描述:SENSOR, PT100, THIN FILM, 2X10MM, CL B 制造商:LABFACILITY 功能描述:SENSOR, PT100, THIN FILM, 2X10MM, CL B; Sensing Temperature Min:-50C; Sensing Temperature Max:+600C; Approval Bodies:IEC; Approval Category:Class B; External Length / Height:10mm; External Width:2mm; Measuring Range:-50C to ;RoHS Compliant: Yes
DM-334
制造商:Labfacility Limited 功能描述:SENSOR PT100 THIN FILM 2X10MM CL A 制造商:Labfacility Limited 功能描述:SENSOR, PT100, THIN FILM, 2X10MM, CL A 制造商:Labfacility Limited 功能描述:SENSOR, PT100, THIN FILM, 2X10MM, CL A, Lead Length:10mm, Sensing Temperature Mi 制造商:Labfacility Limited 功能描述:SENSOR, PT100, THIN FILM, 2X10MM, CL A, Lead Length:10mm, Sensing Temperature Min:-50C, Sensing Temperature Max:+400C, Approval Bodies:IEC, Approval Category:Class A, External Length / Height:10mm, External Width:2mm, Material:Thin, RoHS Compliant: Yes