Abstract
In this paper, we propose a new scheme to directly power a 4.9-5.6GHz LC oscillator from a recursive switched-capacitor DC-DC converter. A finite-state machine is integrated to automatically adjust the conversion ratio and switching frequency of the converter such that its DC output voltage is within ±5% of the desired 1V across input voltage range 1.3-2.2V and < 2mA load current conditions. A gate-driver circuit is embedded in each switch of the converter to guarantee constant on-resistance across PVT variations without sacrificing device reliability. Furthermore, a spur reduction block (SRB) is embedded in the oscillator to suppress the ripple induced spurs by stabilizing its tail current. Both the converter and the oscillator are implemented in 40-nm CMOS technology. The measured peak power efficiency of the converter is 87%, while its spot noise is < 1.5nV/Hz which does not degrade the phase noise of the oscillator. The SRB suppresses the spur to <-65dBc under the 30mVpp ripple of the converter.
Original language | English |
---|---|
Pages (from-to) | 3764-3777 |
Number of pages | 14 |
Journal | IEEE Transactions on Circuits and Systems I: Regular Papers |
Volume | 67 |
Issue number | 11 |
DOIs | |
Publication status | Published - 2020 |
Bibliographical note
accepted author manuscriptKeywords
- LC oscillator
- LDO replacement
- Switched-capacitor DC-DC converter
- gate-driver circuit
- phase noise
- spur reduction block
- voltage controlled oscillator (VCO)