Fully Integrated, 100-mV Minimum Input Voltage Converter With Gate-Boosted Charge Pump Kick-Started by LC Oscillator for Energy Harvesting

Abstract

A fully integrated step-up DC-DC converter for energy harvesting applications is presented. A minimum startup voltage of 100 mV is achieved by the startup mechanism based on an LC oscillator (LCO). Conventional voltage converters with the LCO-based startup mechanism provide a significantly low conversion efficiency of around 1%. To overcome this drawback, the following two circuit techniques are proposed in this brief: 1) a gate-boosted charge pump and 2) an LCO deactivation. The proposed voltage converter is fabricated in the 65nm silicon on thin buried oxide (SOTB) process. The measurement results show that when the input voltage is 100 mV, the proposed converter can provide an output of 760 mV at a conversion efficiency of 33%, which is the highest efficiency compared with the conventional fully integrated voltage converters.

A Review of Charge Pump Topologies for the Power Management of IoT Nodes

“…Electronics 2018, 7, x FOR PEER REVIEW 2 of 14 extracted from surrounding environment, towards a storage buffer. Hence, presently their field of application includes energy-autonomous systems, such as battery-less circuits, biomedical implants and, more recently, IoT nodes [1][2][3][4][12][13][14][15][16][17][18][19][20][21][22][23]. In this latter context, the design of a PMIC based on CPs is a challenging task since it must fulfill a very low input voltage supply (few hundreds of millivolts and high-power conversion efficiency).…”

“…Thus, the CP efficiency and driving capability are improved at the cost of an additional circuit to generate the boosted signal. More recently, Fuketa et al [12] introduced a modified bootstrap CP in which phases φ 1b and φ 1b are switched between 0 and the output voltage to further increase performance.…”

“…Analysis of data reported in Table 1 reveals that the lowest minimum supply voltage is achieved by the cross-coupled topology in [2] thanks to the adoption of an auxiliary CP for startup. Unexpectedly, solutions adopting gate and body control schemes, [12][13][14][15][41][42][43], show higher minimum supply voltages, thus showing that the comparison among the different designs is not straightforward because of the different functionality and constraints required by the various applications.…”

“…Charge pumps have been traditionally adopted in nonvolatile memories and SRAMs, in which the design is driven by settling time and low area, or RF antenna switch controllers and LCD drivers, where the main design constraint is the current drivability [9][10][11]. More recently, CPs are widely used to adapt the voltage levels between two or more functional blocks and to convey the electric energy, and, more recently, IoT nodes [1][2][3][4][12][13][14][15][16][17][18][19][20][21][22][23]. In this latter context, the design of a PMIC based on CPs is a challenging task since it must fulfill a very low input voltage supply (few hundreds of millivolts and high-power conversion efficiency).…”

Light-Powered Starter for Micro-Power Boost DC–DC Converter for CMOS Image Sensors

“…Because of the need for the off-chip transformer and because JFET is not compatible with CMOS technology, these approaches are limited in application. Another solutions [4,12,18] use an LC oscillator based on very-low-threshold-voltage MOS transistors and a Dickson charge pump to generate a sufficiently high start-up voltage.…”