An Integrated DC-DC Converter With Segmented Frequency Modulation and Multiphase Co-Work Control for Fast Transient Recovery

This paper presents a fully integrated voltage-controlled oscillator (VCO)-based switched-capacitor (SC) 15-phase dc-dc converter in 65-nm CMOS. We propose two transient-enhancement techniques: segmented frequency modulation (SFM) and multiphase co-work (MCW) control to reduce the latency of the VCO...

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Bibliographic Details
Published in:IEEE journal of solid-state circuits 2019-10, Vol.54 (10), p.2637-2648
Main Authors: Chio, U-Fat, Wen, Kuo-Chih, Sin, Sai-Weng, Lam, Chi-Seng, Lu, Yan, Maloberti, Franco, Martins, Rui P.
Format: Article
Language:English
Subjects:
Capacitors
Charge pumps
CMOS
Converters
Frequency modulation
Fully integrated
Generators
Multiphase
Recovery
Response time
SC dc–dc converter
Steady-state
switched capacitor (SC)
Transient analysis
Transient response
Voltage control
Voltage controlled oscillators
voltage-controlled oscillator (VCO)
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Summary:This paper presents a fully integrated voltage-controlled oscillator (VCO)-based switched-capacitor (SC) 15-phase dc-dc converter in 65-nm CMOS. We propose two transient-enhancement techniques: segmented frequency modulation (SFM) and multiphase co-work (MCW) control to reduce the latency of the VCO-based control loop and shorten the SC dc-dc converter's transient response time. The SFM can improve the heavy-to-light load transient by dynamically increasing the charge pump discharge current by nine times, while the MCW can enhance the light-to-heavy load recovery by synchronously combining three interleaved flying capacitors together during the transient state. We designed the 15-phase interleaved converter to support an output voltage of 1 V from a 2.4-V input supply, delivering up to 138 mA of load current, which takes only 25/29 ns for output voltage recovering to the steady state from heavy-to-light/light-to-heavy load transients, respectively. It obtains a peak efficiency of 82.8% and maintains the efficiency above 80% from 31 mA to the maximum load current. The SC dc-dc converter chip occupies 0.61 mm 2 , and its output power density is 240 mW/mm 2 .
ISSN:0018-9200
1558-173X
DOI:10.1109/JSSC.2019.2924092