A DC-DC charge pump design based on voltage doublers

Abstract

A novel organization of switched capacitor charge pump circuits based on voltage doubler structures is presented in this paper. Each voltage doubler takes a dc input and outputs a doubled dc voltage. By cascading voltage doublers the output voltage increases up to 2 times. A two-phase voltage doubler and a multiphase voltage doubler (MPVD) structures are discussed and design considerations are presented. A simulator working in the -realm was used for simplified circuit level simulation. In order to evaluate the power delivered by a charge pump, a resistive load is attached to the output of the charge pump and an equivalent capacitance is evaluated. A comparison of the voltage doubler circuits with Dickson charge pump and Makowski's voltage multiplier is presented in terms of the area requirements, the voltage gain, and the power level. This paper also identifies optimum loading conditions for different configurations of the charge pumps. Design guidelines for the desired voltage and power levels are discussed. A two-stage MPVD was fabricated using MOSIS 2.0-m CMOS technology. It was designed with internal frequency regulation to reduce power consumption under no load condition.

A Regulated Charge Pump With Small Ripple Voltage and Fast Start-Up

“…The output load capacitor is charged only during pumping period and discharged through the load resistor continuously. If the pumping period is much shorter than the blocking period, output ripple voltage at the load capacitor during the pumping period [4] is determined by (1) where is the pumping current into the flying capacitor during the pumping and blocking periods which is equal to in a steady state, is the output load capacitance, and is the switching frequency between the pumping and blocking periods. To reduce output ripple voltage, voltage variation during the pumping and blocking periods should be minimized.…”

“…N MANY semiconductor devices, such as DRAM, EEPROM, and switched-capacitor transformers, charge pumps are frequently used to provide voltage higher than a power supply because high voltage level in a charge pump is generated by transferring charge to a capacitive load, without any amplifiers or regular transformers [1]. Many charge pump approaches have focused on the design of the Dickson charge pump, such as [2]- [4], since the conventional applications have required a high voltage with only limited current drive capability.…”

Optimization of the Voltage Doubler Stages in an RF-DC Convertor Module for Energy Harvesting

“…The energy conversion module designed in this paper is based on a voltage doubler circuit which can be able to output a DC voltage typically larger than a simple diode rectifier circuit as in [5], in which switched capacitor charge pump circuits are used to design two phase voltage doubler and a multiphase voltage doubler. The module presented in this can function as an AC to DC converter that not only rectifies the input AC signal but also elevates the DC voltage level.…”

Area-driven optimisation of switched-capacitor DC/DC converters

“…Series-parallel converter: When a series-parallel converter [1] is implemented the output voltage increases linearly with the number of stages. Thus the VCR of this N-stage series-parallel converter is N þ 1 ¼ k þ 1.…”

“…The ideal VCR is 2 N , in which N is the number of stages. Charge balance techniques [2] are used to determine the output voltage in (1). In order to maximise the output voltage for a certain number of stages N, the second term of this equation is minimised.…”