Avago ACPL-782T汽车用小型绝缘放大方案

Avago 公司的ACPL-782T是汽车用小型绝缘放大器,适用于马达驱动和电池系统监测的电压和电流检测.ACPL-782T采用先进的Delta-Sigma ADC技术,增益误差±2%,增益漂移30ppm/℃,输入失调电0.3mV,100kHz带宽,非线性0.004%.本文介绍ACPL-782T主要特性,功能方框图以及输入失调电压, 增益和非线性和传输时延测试电路图, 电压检测和温度检测应用电路图.

ACPL-782T-000E: Plastic Automotive Miniature Isolation Amplifier

The ACPL-782T isolation amplifier was designed for voltage and current sensing in electronic motor drives and battery system monitoring. In a typical implementa­tion, and motor currents flow through an external resistor and the resulting analog voltage drop is sensed by the ACPL-782T. A differential output voltage is created on the other side of the ACPL-782T optical isolation barrier. This differential output voltage is proportional to the motor current and can be converted to a single-ended signal by using an op-amp as shown in the recommended ap­plication circuit. Since common-mode voltage swings of several hundred volts in tens of nanoseconds are common in modern switching inverter motor drives, the ACPL-782T was designed to ignore very high common-mode transient slew rates (of at least 10 kV/μs).

The high CMR capability of the ACPL-782T isolation amplifier provides the precision and stability needed to ac­curately monitor motor current and DC rail voltage in high noise motor control environments, providing for smoother control (less “torque ripple”) in various types of motor control applications.

The product can also be used for general analog signal isolation applications requiring high accuracy, stability, and linearity under similarly severe noise conditions.The ACPL-782T utilizes sigma delta (Σ−Δ) analog-to-digital converter technology, chopper stabilized amplifiers, and a fully differential circuit topology.

Together, these features deliver unequaled isolation-mode noise rejection, as well as excellent offset and gain accuracy and stability over time and temperature. This performance is delivered in a compact, auto-insert­able, industry standard 8-pin DIP package that meets worldwide regulatory safety standards. (A gull-wing surface mount option -300E is also available).

ACPL-782T主要特性:

• ±2% Gain Tolerance @ 25℃

• 15 kV/μs Common-Mode Rejection at VCM = 1000V

• 30ppm/℃ Gain Drift vs. Temperature

• 0.3 mV Input Offset Voltage

• 100 kHz Bandwidth

• 0.004% Nonlinearity

• Compact, Auto-Insertable Standard 8-pin DIP Package

• Worldwide Safety Approval:

– UL 1577 (3750 VRMS/1 min.)and

– CSA

– IEC/EN/DIN EN 60747-5-5

• Qualified to AEC-Q100 Test Guidelines

• Automotive Operating Temperature -40 to 125℃

• Advanced Sigma-Delta (Σ−Δ) A/D Converter Technology

• Fully Differential Circuit Topology

ACPL-782T 应用:

• Automotive Motor Inverter Current/Voltage Sensing

• Automotive AC/DC and DC/DC converter Current/ Voltage sensing

• Automotive Battery ECU

• Automotive Motor Phase Current Sensing

• Isolation Interface for Temperature Sensing

• General Purpose Current Sensing and Monitoring


图1.ACPL-782T功能方框图

图2.ACPL-782T输入失调电压测试电路图

图3.ACPL-782T增益和非线性测试电路图

图4.ACPL-782T传输时延测试电路图

图5.ACPL-782T电源和传感电阻连接图

图6.ACPL-782T应用电路图

图7.ACPL-782T电压检测应用电路图

图8.ACPL-782T温度检测应用电路图