A pcb surface mounted shape memory alloy fuse

Abstract

The invention relates to a PCB surface-mounted shape memory alloy fuse which comprises an arched conductive sheet made from shape memory alloy and two bonding pads arranged on a PCB and used for disconnecting a circuit. The shape memory effect of the shape memory alloy is a single-stroke shape memory effect. Bonding sheets which can be welded on the two bonding pads are arranged at two ends of thearched conductive sheet respectively. Two jacks formed in a spaced mode are formed in the edge of one bonding pad on the PCB, and two plug pins correspondingly plugged into the jacks and fixing the arched conductive sheet on the PCB are arranged at the bottom of one bonding sheet. Due to the fact that the arched conductive sheet is made from the alloy having the single-stroke shape memory effect,a tensioning state is formed without additional device bending deformation, the arched conductive sheet does not get loose during bouncing through matching of the jacks and the plug pins, circuit re-connection can be avoided, and the PCB surface-mounted shape memory alloy fuse is simple and compact in structure, convenient to machine and low in price.

Description

technical field [0001] The invention relates to the field of overheating protection of PCB circuits, in particular to a PCB surface-mounted shape memory alloy fuse in a high-power, high-current electronic module. Background technique [0002] High-power and high-current electronic modules are becoming more and more popular, such as: motor controller MCU, anti-lock brake electronic module ABS / ESP, electric power steering electronic module EPS, battery controller BMS, high-power amplifier Power Amplifier, DC conversion DC-DC Converter, inverter Inverter, etc.; PCBs in these electronic modules are often loaded with high-current or high-power circuits. In extreme failure conditions such as motor stalling for a long time or circuit overload, the circuit board will burn out, or even the entire component Therefore, it is necessary to add an overheating protection device, such as a fuse, in the hardware circuit design of the electronic module to cut off the circuit to avoid the hidd...

AI Technical Summary

Problems solved by technology

[0003] At present, PCB patch type fuses are commonly used in small boxes, such as TE RTP200R060SA. When the ambient temperature at the fuse position reaches the trigger temperature, the internal spring releases and disconnects the internal contacts to disconnect the entire circuit; although its size is very compact, its structure It is very complicated and expensive, and after reflow soldering, additional mechanical actions are required, or the fuse is loaded with a large current to fuse the internal structure, in order to tension the internal fine spring structure

In addition, there is also a type of shrapnel fuse, refer to patents US005612662A, US008665057B2, this type of fuse is usually a slender leaf spring style, the two ends of the shrapnel are welded together with the contacts on the PCB to form a path, when the ambient temperature around the fuse When the melting temperature of the solder is reached, the tensioned part of the shrapnel is released and bounced to achieve the purpose of disconnecting the circuit; although its structure is simple, easy to process, and low in price, it is assembled on the surface of the PCB board through patch and reflow soldering, but After reflow soldering, the elastic arm structure on the fuse needs to be bent and deformed by special equipment to form a tensioned state. At the same time, there is no other mechanical fixation between it and the PCB board. During the pop-up and release process, the fuse will jump freely or even loose, which will make The circuit has the possibility of being connected again, and due to the needs of the tension structure, the size of the elastic arm needs to be designed to be slender, thereby increasing the overall structural size and occupying the space of the PCB board, which is not conducive to the design direction of product miniaturization and trends

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