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The paper addresses a re-design and parameter analysis of a current-mode rail-to-rail voltage comparator with power consumption in nano-watt range across all PVT corners. The comparator design was done in general-purpose 65 nm CMOS technology with the nominal power supply voltage of 1.2 V. The circuit design needs to function properly in industrial temperature range that is from -20 ◦ C to 85 ◦ C. The rail-to-rail input voltage range is achieved without employing two differential pairs and also without an internal voltage biasing circuitry. Furthermore, the design process can be easily automated by means of calculation spreadsheet and employing gm /ID design methodology. The presented comparator has been analyzed for robustness and accuracy across all process and temperature corners using post-layout extracted netlist, and some parameters were also investigated through Monte-Carlo analysis. The power consumption does not exceed 1 µW in the worst-case scenario, however in typical PVT conditions, it remains below the first third of nano-watt range. The circuit also contains enable signal to minimize the power consumption down to leakage level when the circuit’s function is not required. The topology itself, exhibits a promising potential for further research, since it can also work in ultra low-voltage regime thanks to only two stacked transistors.

The article addresses a novel topology of analog voltage comparator capable of processing the input voltage in rail-to-rail range. We propose two different innovative comparator topologies. One topology is employing a standard “gate-driven” (GD) control of MOS transistors and designed in 65 nm CMOS technology. The other one, designed in 130 nm CMOS technology, uses rather unconventional “bulk-driven” (BD) control of active devices in the circuit. Each presented circuit topology has its own pros and cons, however both are suitable and actually aimed for ultra low-voltage (ULV) and/or ultra low-power (ULP) applications. The proposed comparator designs have been extensively analyzed for robustness and parameter stability across all fabrication process corners, a wide temperature range (from -20 ◦ C to 85 ◦ C), and for random process variations, as well. Both presented comparator designs can reliably operate with power consumption in nano-watt range without any fuse trimming or calibration, as the proof of concept has been confirmed by measurements performed on prototype chips.

The paper addresses a development and application of EKV MOS transistor compact model with focus on the ultra low-voltage / ultra low-power analog integrated circuit (IC) design employing bulk-driven (BD) technique. The presented contribution can be viewed as an extension of standard EKV model application and as a contribution to ultra low-voltage IC design techniques. The paper compares the measured and extracted small-signal parameters of standalone transistor samples fabricated in 130 nm CMOS technology and the simulation results obtained using the proposed bulk-driven EKV v2.63 model and foundry-provided BSIM model v3.3. The transistor samples were analyzed with power supply of V DD = 0.4 V The paper also discusses the implementation of 3D graphs as a result of introducing another degree of freedom into the essential MOS transistor characteristics, while maintaining the ease of using the design hand-calculation with the original g m /I D approach.

The paper brings an overview of main challenges in implantable medical devices (IMD) research area, where the main objective of discussion covers wireless power transferring (WPT) systems as the hot topic dedicated to energy harvesting that is still gaining in popularity. The paper is focused on electromagnetic-transfer principle, where full integration of the WPT systems on a chip is taken as the primary goal covering passive transducer and rectifier implementations. The presented research reveals many issues raised from the state of the art solutions. These solutions can or should be detailed investigated in the future research. Therefore, this paper discusses about so far hidden potential of fully integrated WPT systems, where both near-field and far-field approaches are included. Additionally, the discussion is also extended to a principle of power transfer efficiency (PTE) maximization through approaches such as matching and finding the optimal source/load together with rectifying and regulating issues.

The power saving issue as well as clean energy harvesting for wireless and cost-affordable electronics (e.g. IoT applications, sensor nodes or medical implants), belong to very attractive research topics recently. With this in mind, the paper addresses one of the most important parts of the energy conversion system chain – the power management unit. The core of such a unit will be formed by an inductor-less, low-voltage DC-DC converter based on the cross-coupled dynamic-threshold charge pump topology. The charge pump utilizes a power-efficient ON/OFF regulation feedback loop, especially designed for strict low-voltage start-up conditions by a driver booster. Together, they serve as the masters to control the charge pump output (up to 600 mV), depending on the voltage value produced by a renewable energy source available in the environment. Low-power feature is also ensured by a careful design of the hysteresis-based bulk-driven comparator and fully integrated switched-capacitor voltage divider, omitting the static power consumption. The presented converter could also employ the on-chip RF-based energy harvester for use in a wireless power transfer system.

The power saving issue as well as clean energy harvesting for wireless and cost-affordable electronics (e.g. IoT applications, sensor nodes or medical implants), belong to very attractive research topics recently. With this in mind, the paper addresses one of the most important parts of the energy conversion system chain – the power management unit. The core of such a unit will be formed by an inductor-less, low-voltage DC-DC converter based on the cross-coupled dynamic-threshold charge pump topology. The charge pump utilizes a power-efficient ON/OFF regulation feedback loop, especially designed for strict low-voltage start-up conditions by a driver booster. Together, they serve as the masters to control the charge pump output (up to 600 mV), depending on the voltage value produced by a renewable energy source available in the environment. Low-power feature is also ensured by a careful design of the hysteresis-based bulk-driven comparator and fully integrated switched-capacitor voltage divider, omitting the static power consumption. The presented converter could also employ the on-chip RF-based energy harvester for use in a wireless power transfer system.

The paper brings an overview of main challenges in implantable medical devices (IMD) research area, where the main objective of discussion covers wireless power transferring (WPT) systems as the hot topic dedicated to energy harvesting that is still gaining in popularity. The paper is focused on electromagnetic-transfer principle, where full integration of the WPT systems on a chip is taken as the primary goal covering passive transducer and rectifier implementations. The presented research reveals many issues raised from the state of the art solutions. These solutions can or should be detailed investigated in the future research. Therefore, this paper discusses about so far hidden potential of fully integrated WPT systems, where both near-field and far-field approaches are included. Additionally, the discussion is also extended to a principle of power transfer efficiency (PTE) maximization through approaches such as matching and finding the optimal source/load together with rectifying and regulating issues.