비구동 플레이트 FRAM을 위한 온칩 음전압 발생기
On-chip negative voltage generator for non-driven plate FRAM core module
음전압 발생기;전하펌프;비구동 플레이트;
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In this thesis, a negative voltage generator which provides different two negative voltages (-V_(DD) , -V_(PP)) for non-driven plate FRAM core module is presented. It can be applied to any memory chip, other IC applications and so on. The basic architecture is consist of 4 stages: power detector, voltage detector, oscillator and negative charge pump. Power detector is designed for the chip operate when V_(DD) is up to 2.0V. Voltage detector is designed to detect each negative voltage when negative charge pump generates desired voltage. Ring oscillator provides input pulse signal into charge pump. The developed oscillator is less sensitive at temperature or V_(DD) variation and more stable than ring oscillator. Negative charge pump consists of capacitors and diodes connected MOSFET which is designed to have characteristics of ideal diode. The -V_(DD) and -V_(PP) negative voltages settle to the target value 1.5㎲ after starting the negative pumping. 10 stages negative charge pump are used to provide -V_(DD) and 14 stages for -V_(PP). Their current supply capabilities are 970㎂ for -V_(DD) and 728㎂ for -V_(PP) at 2.5V, 25℃ and oscillation pulse period of 20㎱.