Through silicon via (TSV) based 3-D integrated circuits (IC) permit the integration of heterogeneous technologies with CMOS. The integrated system may include RF, analog, micro/nano-electromechanical systems (MEMS/NEMS) as well as emerging technologies such as nano-FET and graphene-based device planes. The design and fabrication of these disparate device planes may take place at separate facilities. Unless technology specific information on each device plane is provided, the packaging facility carrying out the final 3-D integration of the device planes is unaware of the power supply voltage requirements of the different ICs.

Drexel researchers have developed a circuit technique to detect the power supply voltage requirement of each voltage domain in each device plane of the 3-D IC stack. The circuit consists of 1) a ring oscillator in each voltage domain located in each device plane, and  2) a power module placed in a dedicated power plane.  Two different circuit implementations of the power module have been developed which provide a precise reference voltage to on-chip voltage regulators (LDO or DC-DC switching buck converter).  The power module supports DVFS and can provide the desired power supply voltage for advanced CMOS technology nodes (45 nm and beyond) in less than 100 ns.  The voltage detection circuit also clamps the voltage to the desired level thus providing an elegant solution to power supply voltage variations due to PVT.