A Wide Load Current and Voltage Range Switched Capacitor DC–DC Converter with Load Dependent Configurability for Dynamic Voltage Implementation in Miniature Sensors

Abstract

Advancements in low power circuits and batteries have enabled the design of miniature sensors with tiny batteries. In such systems, implementing dynamic voltage scaling (DVS) is crucial for maximizing system lifetime. In this paper, a new switched capacitor (SC) converter that is capable of handling a wide range of load currents and output voltages is presented for on-chip DVS implementation. The proposed converter consists of multi-ratio multi-leaf SC stages and reconfigurable interconnect, enabling fine voltage resolution. The stage interconnect scheme enables cascaded or parallel connection of stages. The multi-leaf structure allows load-dependent switch size selection, offering a better trade-off between losses over a wide load range. A limited-voltage-swing switch-driving scheme allows efficient down-conversion from high battery voltage input. A prototype was fabricated in a 180 nm process, providing an output voltage with effective resolution of 16 mV over a load current range of 300 nA to 300 μA (1000×) from a 4 V battery. Efficiency greater than 62% and a peak efficiency of 77% are achieved under a light load (500 nA) over a voltage range of 400 mV to 1.6 V. Efficiency greater than 64% and a peak efficiency of 72% are achieved under a heavy load (200 μA) over a voltage range of 700 mV to 1.6 V.

A High Conversion Ratio DC–DC Boost Converter with Continuous Output Current Using Dual-Current Flows

“…From Equation (10), as D changes from 0 to 1, M HVDF is always larger than 1.5, which means that the system can operate as a boost converter for high-voltage outputs. Owing to the two flying capacitors C F1 and C F2 , the HVDF avoids the problems associated with the CBC.…”

“…Among various DC-DC converters, a charge pump (CP) is capable of generating high-voltage gains using several capacitors. However, generating an output voltage that differs from a predetermined voltage gain can lead to rapid efficiency degradation [7][8][9][10][11][12]. Additionally, the capacitances need to become very large to use CP in heavy load applications.…”

A High-Voltage Energy-Harvesting Interface for Irregular Kinetic Energy Harvesting in IoT Systems with 1365% Improvement Using All-NMOS Power Switches and Ultra-low Quiescent Current Controller

“…To provide efficient operation over a wide range of input with varying period, the CK frequency is made tunable from 10 Hz to 1 kHz. For VPD clock ( CK ) generation, a leakage control clock generator [21], which provides frequency tunability by controlling leakage control voltage ( V CONT ), and consumes 110 pJ/ CK _cycle have been adopted. The details of the adopted CK generator have been shown in supplementary Figure S2.…”

Fully Integrated Low-Ripple Switched-Capacitor DC–DC Converter with Parallel Low-Dropout Regulator

“…For portability, such devices/applications are usually powered by small batteries, which limit the operating time of sensor-based devices. Therefore, in order to increase the battery efficiency to provide longer operating times, power management units such as power management integrated circuits (ICs) are used to control power consumption [2,3]. The power management IC can be mounted on the same printed circuit board as the sensor IC, as shown in Figure 1a.…”