Active Filter-Based Hybrid On-Chip DC-DC Converter for Point-of-Load Voltage Regulation

An active filter-based on-chip DC-DC voltage converter for application to distributed on-chip power supplies in multivoltage systems is described in this paper. No inductor or output capacitor is required in the proposed converter. The area of the voltage converter is therefore significantly less than that of a conventional low-dropout (LDO) regulator. Hence, the proposed circuit is appropriate for point-of-load voltage regulation for noise sensitive portions of an integrated circuit. The performance of the circuit has been verified with Cadence Spectre simulations and fabricated with a commercial 110 nm complimentary metal oxide semiconductor (CMOS) technology. The area of the voltage regulator is 0.015 mm(2) and delivers up to 80 mA of output current. The transient response with no output capacitor ranges from 72 to 192 ns. The parameter sensitivity of the active filter is also described. The advantages and disadvantages of the active filter-based, conventional switching, linear, and switched capacitor voltage converters are compared. The proposed circuit is an alternative to classical LDO voltage regulators, providing a means for distributing multiple local power supplies across an integrated circuit while maintaining high current efficiency and fast response time within a small area.