Spurious noise reduction by modulating switching frequency in DC-to-DC converter for RF power amplifier

The presence of a spectrum spreading effect in a DC-to-DC converter operating in Pulse-Width Modulation (PWM) with a modulated switching frequency is analyzed. A step-down DC-to-DC converter prototype with a digital PWM ramp signal modulator is implemented in a standard CMOS 0.18-μm process. The ste...

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Bibliographic Details
Published in2010 IEEE Radio Frequency Integrated Circuits Symposium pp. 43 - 46
Main Authors Eung Jung Kim, Chang-Hyuk Cho, Woonyun Kim, Chang-Ho Lee, Laskar, Joy
Format Conference Proceeding
LanguageEnglish
Published IEEE 01.05.2010
Subjects
DC-DC power converters
DC-to-DC converter
Frequency modulation
modulated PWM
Noise reduction
Power amplifiers
Pulse width modulation
Pulse width modulation converters
Radio frequency
Radiofrequency amplifiers
spread spectrum
switch power supply
Switching converters
Switching frequency
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Summary:The presence of a spectrum spreading effect in a DC-to-DC converter operating in Pulse-Width Modulation (PWM) with a modulated switching frequency is analyzed. A step-down DC-to-DC converter prototype with a digital PWM ramp signal modulator is implemented in a standard CMOS 0.18-μm process. The step-down DC-to-DC converter has an 6-bit up/down binary counter to vary its switching frequency between 2.2 MHz and 4.4 MHz in 64 steps as means of decreasing spurious noise peaks at the output of the switch converter. The measurement results show that the spurious switch noise peak is reduced by 12 dB when a monotonic frequency stepping with the up/down counter is used, and it is shown that the additional switching frequency modulation functionality does not degrade the overall efficiency and the closed loop operation significantly.
ISBN:9781424462407
1424462401
ISSN:1529-2517
2375-0995
DOI:10.1109/RFIC.2010.5477360