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This paper presents a dynamic voltage scaling (DVS) compatible single-inductor multiple-output (SIMO) voltage regulation module that enables smaller passives for a given output power, while maintaining power quality (low output ripple), suppressing cross regulation, and improving efficiency at high switching frequency. First, continuous-conduction mode (CCM) operation is utilized to deliver higher output power for a smaller inductance; the cross-regulation in CCM operation is suppressed using a novel power-weighted CCM controller. Second, a modified power stage filter is presented using floating capacitors that utilize the Miller effect to reduce the switching frequency of the output, while maintaining the power quality. The operating principles, stability, and circuit level design of the proposed SIMO VR are presented. The design is demonstrated through a 130-nm CMOS test chip that generates four outputs, each ranging from 200 to 600 mV, from a 1.2-V input. The measurements demonstrate a 20-MHz operation, the pulse width modulation signal of the power stage with 500-nH inductor, and 1-μF total load capacitance, while delivering a output power density of 150 mW/μH·μF. The test chip demonstrates DVS speed of 120 mV/μs, 73% peak efficiency at a load of 40 mA, and as high as 40% efficiency improvement using the modified power filer. [ABSTRACT FROM AUTHOR]

Self-powered wireless sensors require power delivery systems capable of harvesting from very low input voltage while consuming minimal bias current. This paper presents a multistage boost regulator capable of generating 3 V to supply RF blocks in self-powered wireless sensors from 10 mV input voltage. The bias power consumption is minimized using automated bias gating. The efficiency of the multistage conversion at a high conversion ratio is enhanced through the regulation and control of the intermediate-node voltage. A test chip, fabricated in 130 nm CMOS, demonstrates functional operation from as low as 10 mV input and consumes 190 nA bias current. Single-stage boost regulator demonstrates Peak efficiency of 89%, while the cascaded two stage peaks at 72%. In the cascaded system, the variable intermediate-node voltage operation shows up to 9% efficiency improvement over fixed intermediate-node voltage when operating at high conversion ratio. [ABSTRACT FROM PUBLISHER]

An inductive boost regulator is presented that can harvest energy over a wide input voltage range. The wide input range is enabled by a current-based analog oscillator capable of providing very high duty cycle. The analog control circuits are designed to operate at subthreshold voltage to enable low voltage all electronic autonomous startup. A test chip designed in 130-nm CMOS demonstrates energy harvesting from as low as 12-mV input while biased by an external 1-V battery and autonomous (without using any additional device or battery) startup above 305 mV at output. The design typically consumes 3.5-μA standby current, achieves peak efficiency of 82%, and can regulate output from 0.66 to 3.3 V. The booster is coupled with a thermoelectric generator and the integrated system delivers output power of 6 μW at ~2 °C temperature difference to a maximum of 12 mW at ~50 °C temperature difference. [ABSTRACT FROM AUTHOR]

This article presents a low-overhead energy harvesting and delivery system (EHDS) with pulse frequency modulated (PFM) integrated voltage regulator (IVR) power conversion and self-tuned maximization of system output power. A novel load-inclusive time-based maximum power point tracking (LI-TB-MPPT) is developed to provide centralized tuning of PFM-IVR operation based on both source capabilities and load demand on-the-fly, and a configurable fractional sample and hold circuit provides adaptive harvesting window control. The proposed EHDS enables robust harvesting while relieving the use of high passives, with over two orders of magnitude reduction, at the cost of only slight decrease in end-to-end efficiency compared to prior works. Furthermore, a low-overhead wake-up assist circuit utilizes cold-configuration of harvesting sources for efficient and accelerated cold-start. The proposed EHDS is demonstrated in a 65 nm CMOS process with commercial photovoltaic energy harvesting modules. Using only 1.2 and 1 $\mu$ H of passives, measured results show a peak 74.9% end-to-end efficiency (simulated up to 85% at 47 $\mu$ H) and a fast startup time of 3.8 ms. Up to 15% increase in conversion efficiency against load and input voltage variations is achieved with LI-TB-MPPT. The results demonstrate a compact solution for self-sustained cost-restricted stand-alone systems. [ABSTRACT FROM AUTHOR]

This paper presents a voltage regulator topology, implemented using low-voltage devices, for converting high input voltage (>4.5 V) to low output voltages with fine-grain control (0.3 to 1 V). The topology merges a Dickson's switched-capacitor stage with a current-mode inductive buck stage, and optimizes the frequency of operations to reduce the overall passive size. The proposed two-stage hybrid regulator, designed in 130-nm standard digital process, operates from 4.8 to 6 V at input and regulates output voltage as low as 0.3 V with a maximum output power of 90 mW and a peak efficiency of 69%. [ABSTRACT FROM PUBLISHER]

This article demonstrates all-digital tuning and dynamic control of feedback compensator in digital low drop out regulators to enhance the transient performance under process and passive variations, aging, and load changes. The measured results from a 130-nm CMOS test-chip shows 2.1× improvement in transient performance under process variations and 30% improvement for aging-induced degradations. We demonstrate 55-ns setting time for a 5 to 45 mA load step in 100 ps, with 97.8% peak current efficiency. [ABSTRACT FROM AUTHOR]