.50-bit Automatic High Temperature Reverse Bias Test Bed Hardware And Software Design

As the key components of energy-saving lamps (including electronic ballasts), The power switch transistor plays a key role in energy-saving lamp life.The most important Parameter of transistor is Leakage current in high temperature. Different manufacturers are in addition to the factory of the leakage current characteristics at room temperature under the testing, companies set aside a certain proportion of the high temperature reverse bias test, the test equipment early have a simple function and complicated designed. Application of modern industrial computer and Complex programmable logic device and new DAC / ADC, as same time of simplify the design, increases the stability and multiple functions of equipment while simplifying design.This paper is the product reliability requirements for the company, with modern automatic control technology and chip technology, designed as a fully automatic high-temperature reverse bias of 50 experimental units. The main designs are:1,Precision current detection, the detection range 0-9.999mA;2,Multi-function testing bridge converter;3,Programable high voltage DC supply, voltage range: 0~1000V/500mA;4,50 Road automatic inspection control;5,16-bit high precision D / A, A / D conversion control;6,The software of automatic control and inspection records;There are altogether 50 groups of current detectors, 4 branches each group. The detectors employ negative feedback current detection technique, composed of high precision metal film resistors, micro relays and operational amplifiers. In the multi-functional transforming test bridge high voltage micro relays are used, which can automatically connect or disconnect each pin of the DUT according to the purpose of tests, and therefore increases flexibility of the instrument. Mainly providing a reverse bias for the DUT, programmable high voltage DC supply produces an output which satisfies the design requirements by raising output voltage and current of the operational amplifier in a linear way. Meanwhile, the efficiency of the linear supply is improved by reducing its heat dissipation through controlled input voltage. The automation unit is an industrial computer which controls various functional modules through extended ISA bus and I/O interfaces. The architecture of the circuit is greatly simplified through the application of I/O extension, digital control logic and programmable CPLD.