CMOS-Integrated Temperature Relay Based on Widlar Mirror

摘要

One presents a new variant of temperature relay scheme for CMOS chips, based on a simple structure of voltage source with two cross-connected current mirrors (of modified-Widlar type and simple one). In this scheme the positive feedback is exploited which is designed so that, for a particular temperature the circuit toggles. In this moment his output voltage achieves a level jump, great enough to drive an interface circuit with the relay-signalisation processing part. The relay toggle condition is deduced, which clears up the relay function. The releasing temperature may be programmed in a large range through one or two resistors. The simulation results are presented for the relay conceived in 0.35μm CMOS process. The releasing-temperature process variation is reduced, by a special design procedure, to a maximum value of ±5.5oC.