LOW POWER CMOS INTEGRATED CIRCUIT

摘要

PURPOSE:To reduce or prevent the through currents in a back-up mode by setting the threshold voltage VTN of an n-MOSTR at a high level and the threshold voltage VTP of a p-MOSTR at a low level respectively only in the back-up mode. CONSTITUTION:A CMOS inverter shown in the diagram is driven by a power supply 1 in a normal mode, and VTN-VTP<¦V1¦ is satisfied between the voltage V1 and threshold voltages VTP and VTN of MOSTRs 3 and 4. In this case, the static characteristics of the inverter are equal to those of a conventional type. When the power supply 1 is not applicable, a current is supplied automatically from a power supply 2. The voltage V2 of the power supply 2 is set lower than the voltage V1 to satisfy VTN-VTP>¦V2¦. Thus the TR3 conducts only when 0<=V1n<=V2-¦VTP¦ is satisfied: while the TR4 conducts only when VTN <=V1n