An Optimum Design of Clocked AC-DC Charge Pump Circuits for Vibration Energy Harvesting

Abstract

This paper shows how clocked AC-DC charge pump circuits can be optimally designed to have the minimum circuit area for small form factor vibration energy harvesting. One can determine an optimum number of stages with simple equations and then determine the capacitance of each pump capacitor to have a target output current at a target output voltage. The equations were verified under a wide range of design parameters by comparing the output current with the simulated one. The output current of the circuit designed by the equations was in good agreement with the simulated result, to within 5% for 98% of the 1600 designs with different parameters. We also propose a design flow to help designers determine the initial design parameters of a clocked AC-DC charge pump circuit (i.e., the number of stages, capacitance per stage, and the total size of rectifying devices) under the condition that the saturation current of a unit of the rectifying device, clock frequency, amplitude of the voltage generated by the energy transducer, target output voltage, and target output current are given. SPICE simulation results validated theoretical results with an error of 3% in terms of the output current when a clocked AC-DC charge pump was designed to output current of 1 μA at 2.5 V from a vibration energy harvester with an AC voltage amplitude of 0.5 V.

A Review of Power Management Integrated Circuits for Ultrasound-Based Energy Harvesting in Implantable Medical Devices

“…A possible solution is to exploit blocks which boost the voltage to the needed level (e.g., voltage multipliers or charge pumps). Such circuit can constitute a different building block of the conversion chain or replace the rectifier, acting as AC-DC boost converter [8,30,31]. Figure 8 shows the simplified schemes of the most used charge pump circuits.…”

“…Simplified block diagrams of the architectural solutions just mentioned, are gathered in Figure 11. In [31], it is shown as AC-DC charge pump circuits can be optimally designed to have the minimum circuit area for small form factor vibration energy harvesting. The proposed system (Figure 12) was composed by a passive cross-coupled AC-DC converter without filter, whose rectified output signal feeds a current-controlled ring oscillator and a Dickson CP, whose diodes were implemented by composite CMOS diodes.…”

Primary-side control for the flyback AC–DC converter

“…At present, the flyback converter and forward converter are common lowpower energy conversion circuits. Because of their advantages of simple structure, low cost, and low standby power consumption, they are widely used in AC and DC power adapters and other power management systems (Kawauchi and Tanzawa, 2020;Ye and Tanzawa, 2020;Ishida and Tanzawa, 2021;Zhou et al, 2021). On one hand, their topological structure based on the unique application of transformers to the input and output of the system has excellent electrical isolation effect, avoiding the high-voltage input part and low-voltage output part of the system and the ground wire short circuit caused by the potential safety hazards, compared with the non-isolated power system and isolated power system, therefore having higher security and reliability.…”

Dual Piezoelectric Energy Investing and Harvesting Interface for High-Voltage Input

“…These devices are usually powered with lightweight batteries having low capacity that require frequent battery re-charging or replacement, which is undesirable and sometimes difficult in the case of implantable devices. To achieve energy autonomy, widely investigated energy harvesting sources include RF [1][2][3][4], light [5], heat [6], and vibrations [7][8][9]. Among these sources, vibration energy has been extensively investigated due to the abundance of vibrations in the ambient environment.…”