Finally, the PSRR performance of LDO is studied. An energy-efficient embedded ripple feed-forward path is proposed to improve the PSRR of LDO. Comparing with some state-of-the-art techniques for PSRR improvement, the proposed LDO features very simple structure thus low-power consumption. A LDO implemented in 0.18-mum CMOS technology with 0.042-mm2 active area has been designed to verify the idea. With an external 4.7-muF output capacitor, in the maximum load condition (i.e. at 25 mA), the PSRR is -77 dB at 1 MHz, -85 dB at 2.5 MHz and -55 dB at 5 MHz, respectively. The quiescent current is 15 muA only, while the transient voltage overshoot or undershoot is less than 40 mV when load current changes between 1 mA and 25 mA with 40-ns step time. The LDO achieves good line and load regulations of 3 mV/V and 50 muV/mA, respectively. / Remotely- or battery-powered wireless system-on-a-chip (SoC) needs energy-efficient and high-integration power-management solutions due to their energy-aware characteristics. Low-dropout regulator (LDO) is a good solution because of its excellent performances such as low power consumption, fast load-transient response and high power-supply ripple rejection (PSRR). Moreover, it is easy to be fully integrated since no inductor is needed to be the energy-storage element. Recent development of output-capacitorless LDO (OCL-LDO) realizes on-chip, local voltage regulation to enable more effective integrated power management for SoC. In this thesis, OCL-LDOs with low power consumption and fast load-transient response are investigated and presented in this thesis. LDO with output capacitor for high-PSRR operation to provide clean power supply to RF circuits is also reported. Three LDOs are developed and fabricated to verify the proposed ideas. / The first design is an ultra low-power voltage regulator for remotely powered energy-autonomous devices. It has been fabricated in a commercial 0.18-mum CMOS technology and applied to a passive UHF RFID tag IC. With the low-power voltage reference circuit and sub-threshold operations, the total quiescent current is 700 nA under a 1.8-V power supply. The output voltage of the regulator is 1.45 V with load capability of 50 muA. The temperature coefficients of the voltage reference and the output voltage are only 9 and 43 ppm/°C, respectively. A POR signal with 150-ns-width pulse is also generated to reset the digital processing part in the tag IC. / The second design is a fast-transient OCL-LDO, which has been implemented in a commercial 90-nm CMOS technology. Experimental result verifies that it is stable for a capacitive load from 0 to 50 pF and with load capability of 100 rnA. Moreover, the gain-enhanced structure provides sufficient loop gain to improve line regulation to 3.78 mV/V and load regulation to 0.1 mV/mA, respectively. The embedded voltage-spike detection circuit enables pseudo Class-AB operation to drive the power transistor promptly. The maximum overshoot and undershoot under a 1.2-V supply are less than 66 mV for full load current changes within 100-ns edge time, and the recovery time is less than 5 mus. While the measured power consumption is only 6 muW under a 0.75-V supply. / Guo, Jianping. / Adviser: Ka Nang Leung. / Source: Dissertation Abstracts International, Volume: 73-06, Section: B, page: . / Thesis (Ph.D.)--Chinese University of Hong Kong, 2011. / Includes bibliographical references. / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [201-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstract also in Chinese.
| Identifer | oai:union.ndltd.org:cuhk.edu.hk/oai:cuhk-dr:cuhk_344824 |
| Date | January 2011 |
| Contributors | Guo, Jianping, Chinese University of Hong Kong Graduate School. Division of Electronic Engineering. |
| Source Sets | The Chinese University of Hong Kong |
| Language | English, Chinese |
| Detected Language | English |
| Type | Text, theses |
| Format | electronic resource, microform, microfiche, 1 online resource (xiii, 111 leaves : ill.) |
| Rights | Use of this resource is governed by the terms and conditions of the Creative Commons “Attribution-NonCommercial-NoDerivatives 4.0 International” License (http://creativecommons.org/licenses/by-nc-nd/4.0/) |
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