A BiCMOS Thermal-Shutdown Protection Circuit

Due to the advances in the fabrication process field of integrated circuits, the component density and the overall power dissipation of the high performance VLSI chips increase continuously. Therefore, the increasing thermal state of integrated circuits has been always a great problem concerned. Excessive "hot spot" temperatures due to high power dissipation of a functional circuit in an integrated circuit chip can result in permanent circuit damage if the resulting excessive hot spot temperature is not promptly detected and reduced by turning off or powering down at least part of the functional circuit causing the power dissipation. To overcome this problem, many researchers developed low-power design techniques for VLSI systems. In order to avoid thermal damages, an efficient way is to build temperature sensors and thermal-shutdown protection circuit into all VLSI chips as built-in units. The applications of BiCMOS technology to analog circuit design are ever wider due to its characters of high speed, strong current drive capability, high simulation precision, low voltage, and low power. Designing the multiplexing thermal-shutdown protection circuit which can compatible with BiCMOS technology has important sense.The keys of designing thermal-shutdown protection circuit are the temperature sensor and implementation of thermal-shutdown protection and the important design indexes are low voltage and low power, which are the design emphases in this paper.Based on the character of transistor that V_BE decrease with increase of temperature and ΔV_be increase with temperature, this paper design-ned the temperature sensor, which can detect bidirectionally the change of temperature so as to implement thermal-shutdown protection and solve the problem of thermal scillation. A new BiCMOS thermal-shutdown protection circuit is presented. Simulation with 0.6um BiCMOS technology and comparing with old thermal-shutdown protection circuit...