具有负载电流检测的高速固态继电器接口电路设计

High-speed Solid-state Relay Interface Circuit Design with Load Current Measurement

在姿轨控发动机地面试验中,需要控制快响应电磁阀的开闭,同时准确地测量负载电流;针对应用中的问题,实现了一种高速固态继电器接口电路;设计了用于各路控制信号隔离、逻辑判断和放大的数字控制电路,可切换共正/共负的负载模式,抑制感性负载反电势的负载电路,以及具有隔离输出的电流检测电路;误差分析和测试校准证明本电路对控制信号传输延时不超过150 ns,电流检测精度达到0.2074%,可广泛适用于各种控制器与固态继电器的接口以及电流检测应用中。

In the ground test of attitude and orbit control engine,it is necessary to control the opening and closing of fast response electromagnetic valves,and accurately measure the load current.Aiming at the problems in this application,a high-speed solid-state relay interface circuit was realized.A digital control circuit for the isolation,logical judgment and amplification of all control signals,a load circuit which can switch the common-anode and common-cathode connecting mode of loads and suppress the back EMF(electro-motive force)of inductive load,and a current measurement circuit with isolated output were designed.Error analysis,test and calibration prove that the delay of digital control signal did not exceed 150 ns and the accuracy of current sensing is 0.2074%.This circuit can be widely used in the interface between various controller and solid-state relays,and the application of current measurement.