AD421中文资料

TLP421F

2002-09-25 1 TOSHIBA Photocoupler GaAs IRed & Photo−Transistor

TLP421F

Office Equipment

Household Appliances

Solid State Relays

Switching Power Supplies

Various Controllers

Signal Transmission Between Different Voltage Circuits

The TOSHIBA TLP421F consists of a silicone photo−transistor optically

coupled to a gallium arsenide infrared emitting diode in a four lead

plastic DIP (DIP4) with having high isolation voltage

(AC: 5kVRMS (min)).

Maximum rating and electrical characteristics are the same as TLP421

technical datasheet.

· Collector−emitter voltage: 80V (min)

· Current transfer ratio: 50% (min)

Rank GB: 100% (min)

· Isolation voltage: 5000 Vrms (min)

· UL recognized: UL1577

· BSI approved: BS EN60065: 1994

Approved no. 8411

BS EN60950: 1992

Approved no. 8412

· SEMKO approved: EN60065, EN60950, EN60335

1 概述

+Vs：正电源端，电压范围为2.8～16.5V；

-Vs：负电源端，电压范围为-3.2～-16.5V；

Cc：低阻抗输入端，用于外接低阻抗的输入电压（≤200mV），通常被测电

压需经耦合电容Cc与此端相连，通常Cc的取值范围为10～20μF.当此端作为

输入端时，第2脚VIN应接到COM；

VIN：高阻抗输入端，适合于接高阻抗输入电 压，一般以分压器作为输入级，

分压器的总输入电阻可选10MΩ，以减少对被测电压的分流。该端有两种工作方

式可选择：第一种为输出AC+DC方式。该方式 将1脚（Cc）与8脚（COM）短接，

其输出电压为效流真有效值与直流分量之和；第二种方式为AC方式。该方式是

将1脚经隔直电容Cc接至8脚，这种方式 的输出电压为真有效值，它不包含直

流分量。

COM：公共端；

Vo：输出端；

CF：输出端滤波电容，一般取10μF；

CAV：平均电容。它是AD736的关键外围元件，用于进行平均值运算。其大

小将直接响应到有效值的测量精度，尤其在低频时更为重要。多数情况下可选

33μF.

3 典型应用电路

AD736 有多种应用电路形式。图3为双电源供电时的典型应用电路，该电路

中的+Vs与COM、-Vs与COM之间均应并联一只0.1μF的电容以便滤掉该电路中

的 高频干扰。Cc起隔直作用。若按图中虚线方向将1脚与8脚短接而使Cc失

效，则所选择的就是AC+DC方式；去掉短路线，即为AC方式。R为限流电阻， D1、

D2为双向限幅二极管，超过压保护作用，可选IN4148高速开关二极管。

图4为采用9V电池的供电电路。R1、R2为均衡电阻，通过它们可使

VCOM=E/2=4.5V.C1、C2为电源滤波电容。上述图3和图4电路均为高阻抗输入

方式，适合于接高阻抗的分压器。

图5和图6分别为低阻抗输入方式时，用双电源供电和采用9V单电源供电

时的典型应用电路。

4 注意事项

图7是由AD736构成的简单RMS仪表组成框图。图8是由单片机8098和AD736

a

EVAL-ADF4212EB1FEATURESSelf Contained Evaluation Board including Synthesizer,VCOs, Loop Filters for generating GSM 1800 standards(1700MHz to 1800MHz RF, 520MHz to 560MHz IF).RF and IF filters designed for 20kHz Loop Bandwidth, and200kHz Channel Spacing.Accompanying Software allows complete control of syn-thesizer functions from PC using Windows 95/98/NT.Battery Operated: Choice of 3V or 5V suppliesOn-Board Monitoring of Voltage and CurrentTypical RF Phase Noise Performance of -84dBc/Hz @1kHzoffset.Typical IF Phase Noise Performance of -90dBc/Hz @1kHzoffset.Typical Spurious Performance of batter than -80dBc@200kHz offset.

© Analog Devices, Inc., 1999One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.Tel: 781-329-4700Fax: 781-326-8703Information furnished by Analog Devices is believed to be accurate and reliable. However,no responsibility is assumed by Analog Devices for its use, nor for any infringements ofpatents or other rights of third parties which may result from its use. No license is grantedby implication or otherwise under any patent or patent rights of Analog Devices. Evaluation Board For PLL FrequencySynthesizer

电容式湿度传感器的设计

田海军;薛家兴;薛彦杰

【摘 要】A capacitive humidity sensor is designed for better solving the

low accuracy and high difficulty existing in the moisture measurement of

flowing steam,which is coaxial cylinder multi-polar capacitance sensor

structure,and in which the capacitance digital conversion technology chip

PCap01 is used to detect capacitance value.It transfers measured results to

STM32 microcontroller for data processing by SPI communication.AD421 is

adopted to convert the output results into standard signals of 4～20

mA.The experimental results show that there is a linear relationship

between the output current and the humidity with the change of humidity

at a certain temperature,and when the temperature is not changed,the

output current goes to stability.%为了能够更好解决测量流动蒸汽湿度准确度低、难度大等问题,设计了一种电容式湿度传感器,其为同轴圆筒式多极电容传感器结构,利用电容数字转换技术芯片PCap01进行电容值的检测,通过SPI通信方式将测量结果传输到STM32单片机中进行处理,采用AD421将输出结果转换为标准的4～20 mA信号.实验结果表明,在一定温度下,随着产生湿度的变化,湿度与输出电流呈线性关系,当产生的湿度不变时,电流趋于稳定状态,该设计能够进行湿度的测量.