An Efficient, Wide-Output, High-Voltage Charge Pump With a Stage Selection Circuit Realized in a Low-Voltage CMOS Process

Abstract

A wide-output, power-efficient, high-voltage charge pump with a variable number of stages is proposed and realized in a 0.18 mu m 1.8 V/3.3 V CMOS process. The proposed stage selection circuit changes the node voltages in the charge pump circuit in a domino effect to ensure that the maximum voltages across the terminals of each transistor are kept within the normal supply voltage (V-DD). The stage selection circuit is able to bypass or activate each stage of the charge pump. Experimental results indicate that the proposed charge pump provides a wide-output voltage range: 3.3-12.6 V from a 3.3 V input source. A peak efficiency of 70% was reached in the charge pump at a current loading of 3.5 mA. By selecting the optimal number of active stages, the overall power efficiencies can be greater than 60% under the output voltages of 4.8 V, 8.1 V, and 10.8 V, respectively. By optimizing the number of active stages, an increase of up to 35% power efficiency can be gained. The proposed stage selection circuit is applicable to other on-chip wide-output charge-pumps.