Title :
A DC-DC digitally controlled buck regulator utilizing first-order ∑Δ frequency discriminators
Author :
Ahmad, Hani ; Bakkaloglu, Bertan
Author_Institution :
Ira A Fulton Sch. of Eng., Arizona State Univ., Fulton, AZ
Abstract :
This paper describes a novel feedback digitization architecture for a digitally controlled PWM DC-DC buck converter. A combination of a VCO followed by an all digital first-order Sigma-Delta frequency discriminators (SDFD) is used as a feedback analog-to-digital converter (ADC). The output of the discriminator is decimated to obtain a higher resolution depending on the output ripple specifications. A block diagram and a behavioral model are presented along with simulation results. Based on 1% allowed output voltage ripple, a 8-bit ADC resolution is achieved using a reference clock frequency of 16MHz. Since the SNR of this ADC is a strong function of sampling clock frequency and carrier frequency deviation, it is easy to achieve higher accuracy (resolution) to satisfy wide range of regulation and accuracy requirements. This architecture is flexible and scalable and can fully be implemented in standard digital CMOS.
Keywords :
CMOS integrated circuits; DC-DC power convertors; analogue-digital conversion; digital control; feedback; voltage-controlled oscillators; DC-DC digitally controlled buck regulator; PWM DC-DC buck converter; SNR; VCO; carrier frequency deviation; feedback analog-to-digital converter; feedback digitization; first-order Sigma-Delta frequency discriminators; output ripple specifications; reference clock frequency; sampling clock frequency; standard digital CMOS; Buck converters; Clocks; Delta-sigma modulation; Digital control; Feedback; Frequency; Pulse width modulation; Pulse width modulation converters; Regulators; Voltage-controlled oscillators;
Conference_Titel :
Applied Power Electronics Conference and Exposition, 2008. APEC 2008. Twenty-Third Annual IEEE
Conference_Location :
Austin, TX
Print_ISBN :
978-1-4244-1873-2
Electronic_ISBN :
1048-2334
DOI :
10.1109/APEC.2008.4522745