THESIS
2001
1 v. (various pagings) : ill. ; 30 cm
Abstract
For portable instrument, small size and light weight are essential. Regulated step-up charge pumps require fewer battery cells, need no inductors and thus help in reducing weight and size. Existing regulated charge pumps employ hysteresis control, PWM control or quasi-switch current control. A low drop-out regulator (LDR) is usually inserted to suppress large output ripple for noise-sensitive applications....[
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For portable instrument, small size and light weight are essential. Regulated step-up charge pumps require fewer battery cells, need no inductors and thus help in reducing weight and size. Existing regulated charge pumps employ hysteresis control, PWM control or quasi-switch current control. A low drop-out regulator (LDR) is usually inserted to suppress large output ripple for noise-sensitive applications.
This research presents a regulated charge pump with an integrated switching low drop-out regulator (SLDR). It consists of a dual-cell voltage doubler core with the output PMOS serving as pass transistor of the subsequent LDR. The LDR switches between the two cells and thus is called a switching LDR (SLDR). The control loop consists of a folded cascode operational amplifier for simple compensation and a high slew rate buffer in enhancing bandwidth for good line regulation. To further enhance the bandwidth, a new compensation technique, the dual-loop feedback (DLF), is developed, which reduces the compensation capacitors by hundred times compared to the conventional Miller compensation. The regulated charge pump with integrated SLDR is fabricated using a 0.6μ AMS CMOS process and occupies an area of 3mm
2. The input voltage is 1.8V and the output voltage can be adjusted. The doubler SLDR with DLF has better performance and saves more area, and it combines the advantages of step-up converter and LDR.
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