A Subthreshold Cross-Coupled Hybrid Charge Pump for 50-mV Cold-Start

Abstract

In this paper, a fully-integrated switched-capacitor DC-DC converter based on a Dickson charge pump able to work with input voltage levels that force the transistors working in subthreshold region is presented. The proposed topology exploits resistors in the charge transfer switch in order to overcome the limits of conventional solutions when working in the subthreshold regime. Post-layout simulations using a 28-nm FD-SOI technology show that the CP can boost an input voltage as low as 50 mV to a maximum output voltage of 270 mV, keeping a settling time about 25X lower than the conventional dual-branch cross-coupled charge pump and a voltage conversion efficiency higher than 76%. The proposed topology is particularly suited for the start-up of power management units supplied by thermoelectric generators.

Low-Voltage DC-DC Converter for IoT and On-Chip Energy Harvester Applications

“…However, the converters presented in [ 40 , 41 ] are designed for higher values of the output voltage. Finally, it is important to underline that the proposed topology achieves the best efficiency compared to the works without any MPPT algorithm [ 24 , 44 , 46 , 47 , 48 ]. Therefore, one can assume that the overall efficiency of the designed converter might be improved by using a proper MPPT algorithm.…”

“…Generally, the CCCP has promising potential under low-voltage conditions without applying any special "external" techniques since bootstrapping intrinsically includes such a feature. Despite the few inherited drawbacks, the positives outweigh negatives from a broader perspective [ 22 , 23 , 24 ]. Moreover, recent research proves that if the dynamic- technique is employed to minimize the impedance modulation index, together with careful design based on a parasitics-aware approach, the current throughput and power efficiency can be very optimistic even in the case of the full on-chip implementation [ 17 ].…”

“…Consequently, the proposed CP consists of a stand-alone boosted driver circuit to solve the above-mentioned issue as an alternative to other competitive techniques with different primary purposes in relation to ultra-low voltage research area (e.g., a clock booster based driver, topology reconfiguration approach, implementation of adiabatic principle and many others [ 10 , 24 , 25 ]. The transistor level schematics of the proposed driver and detailed cross-connection with a complementary replica circuit are shown in Figure 3 and Figure 4 , respectively.…”

A Review of Fully Integrated and Embedded Power Converters for IoT

“…(Vdd-VT), where N represents the number of stages, Vdd represents the supply voltage, and VT represents the threshold voltage of the diode-connected MOS transistors. The main limitations of these converters is their inefficiency in transferring charge; therefore, several studies try to improve the voltage gain in every stage and to investigate the energy consumption [10][11][12][13][14][15]. Regarding the classical Dickson charge pump (shown in Figure 4), the main novelty of the recent architectures lies in the use of pass transistors (switches) instead of diode-connected MOS, and/or in more complex timing schemes, as in [10,15,16], or in more expensive technologies like the Silicon On Insulator, which presents several advantages for low-voltage applications [17].…”

Boosting Quantum Battery-Based IoT Gadgets via RF-Enabled Energy Harvesting

“…In this regard, the frameworks and subsequent discussions provided in [ 29 , 30 ] tackle the main blocks used to manage energy in IoT nodes, which can further be translated towards management of the harvested energy for assisting the QB systems. In [ 31 ], the authors discussed power management in ultrasound-based EH in implantable medical devices, where the work is more focused on systems to manage power provided by an alternating current (AC) source (such as rectifiers and rectenna), and solutions for direct current (DC)-type sources are discussed in [ 32 , 33 ].…”