Low voltage integrated charge pump circuits for energy harvesting applications

Pathirana, Walive Pathiranage Manula Randhika
Two different low voltage integrated charge pump circuit topologies are studied in this thesis for energy harvesting applications. The circuits are implemented in 0.18 μm standard CMOS technology without the use of off-chip magnetic components and non-standard processes, and are thus suitable for low profile (small and low cost) system-on-chip applications. In the first proposed design, operation at low input voltage (~240 mV) is achieved with a 5-stage subthreshold first stage oscillator, which improves the first stage efficiency by 28%. The 50 mV hysteretic on-off decision by a comparator at the second stage enables bursts of chargepumping to a standard DC voltage, and thus improves full system efficiency by 2%. The system has been validated in application to generate 1.5 V output with 4% peak efficiency and 0.24 V input voltage. The simulation-validation correlation has been presented in detail. The second proposed system has been developed with fully integrated inductors at the first stage in order to improve the efficiency obtained in the previous design. The system can successfully convert 0.2 V up to 1.5 V with 22% efficiency based on simulations. The generated output power is 31 µW which is 94% higher than that of the previous design. The inductors are modeled using 3D Planar Electromagnetic Field Solver Software incorporating the losses associated with the silicon based spiral inductors. At the ultra-low voltage range of interest, the regulators are estimated to have lower cost and improved efficiency compared to the alternatives reported in literature including the 90 nm two-stage charge pump design previously reported by our team.


Low input voltage and high step-up integrated regulator for thermoelectric energy harvesting
Pathirana, W. P. M. R.; Jayaweera, H. M. P. C.; Muhtaroglu, Ali (2015-03-26)
This paper presents a low input voltage and high step-up fully integrated DC-DC regulator in 0.18 mu m standard CMOS technology for thermoelectric micro-power generation. The circuit avoids off-chip components, non-standard processes, and is thus suitable for ultra-low voltage low profile system-on-chip applications. The proposed system can deliver a regulated output voltage of 1.5 V at 31 mu W output power with an input voltage as low as 0.2 V. The maximum simulated efficiency is 22% at the given step-up r...
Low voltage DC-DC conversion without magnetic components for energy harvesting
Pathirana, W. P. M. R.; Muhtaroglu, Ali (2012-12-05)
A novel interface circuit topology with power management is presented for ultra-low voltage DC-DC step-up conversion. The proposed 90 nm CMOS circuit avoids off-chip components or non-standards processes, and is suitable for ultra-low voltage system-on-chip applications. Comparative analysis was performed with a commercial low voltage DC-DC converter to identify the relative advantages and disadvantages of the integrated approach. The circuit can be started up from input voltage as low as 0.2V based on the ...
Stage Optimization in Regulated Step-Up for Low Voltage Electromagnetic Energy Harvesters
Ulusan, Hasan; Zorlu, Ozge; Külah, Haluk; Muhtaroglu, Ali (2015-03-26)
This paper presents a performance enhancement feature for a novel power management circuit to generate 1.8 V from the low DC voltage rectified at the output of the vibration-based electromagnetic (EM) energy harvesters. The proposed 180 nm circuit utilizes a low voltage charge pump based boost converter with variable output-stages, and an autonomous regulator circuit with negative feedback topology. 2 and 3 stage charge pump options in the variable stage configuration has been validated to extend the suppor...
A Fully Integrated Power Management Circuit for Electromagnetic Energy Harvesting Applications
Gharehbaghi, Kaveh; Ulusan, Hasan; Zorlu, Ozge; Muhtaroglu, Ali; Külah, Haluk (2012-12-05)
In this paper a 90 nm power management circuit for vibration based electromagnetic energy harvesters is introduced to generate 1 V from the rectified DC voltage. A mode selector block is designed to detect the output DC voltage level of the rectifier and adjust the mode of the driver block. In order to set the output to the desired level, a regulation system with negative feedback topology is utilized. The circuit is able to operate with input voltages as low as 0.25 V. The simulation results also show that...
Efficient integrated DC-DC converters for ultra-low voltage energy harvesters
Jayaweera, Herath; Muhtaroğlu, Ali; Sustainable Environment and Energy Systems (2017-8)
The self-starting on-chip fully integrated ultra-low voltage DC-DC converters for energy harvesting applications presented in literature generally have low efficiency and output power capacity. Any improvement in DC-DC converter circuits in terms of energy efficiency, output power, self-starting modes, and voltage gain will contribute significantly to the widespread application of energy harvesters. Two novel fully integrated, self-starting, ultra-low voltage DC-DC converter topologies and model based optim...
Citation Formats
W. P. M. R. Pathirana, “Low voltage integrated charge pump circuits for energy harvesting applications,” M.S. - Master of Science, Middle East Technical University, 2014.