A Surface Mount Flexible Circuit Assembly for Printed Circuit Board Power and Signal Interconnects

摘要

A novel interconnect assembly that combines Flexible Circuit Technology (FCT) and Surface Mount Technology (SMT), along with a rigid contact assembly, is described for an airborne power supply application. The contact assembly brings control signals and up to 16 amperes of current from the input and output pins of a DC-DC converter to pads on an SMT Printed Circuit Board (PCB). Twelve connections are required for each converter. A double-sided flex circuit, seated on the contact assembly, provides solder pads for attaching capacitors and a potentiometer. During prototyping the connections were made by soldering 16-gage wire from each of the converter pins to the PCB. In addition, several in-line capacitors were soldered from copper foil attached to the converter case directly to the converter pins. With 240 converter pin connections required in each power supply assembly, the time and difficulty involved in this assembly step were unacceptable for a production build. The new interconnect assemblies reduce assembly time by 90 percent, increase both connection and PCB reliability, and are electrically superior to the interconnection methods used on the prototype.