Editing Flash memory (section)

===Internal charge pumps===
Despite the need for relatively high programming and erasing voltages, virtually all flash chips today require only a single supply voltage and produce the high voltages that are required using on-chip [[charge pump]]s.

Over half the energy used by a 1.8&nbsp;V-NAND flash chip is lost in the charge pump itself. Since [[boost converter]]s are inherently more efficient than charge pumps, researchers developing [[low-power electronics|low-power]] SSDs have proposed returning to the dual Vcc/Vpp supply voltages used on all early flash chips, driving the high Vpp voltage for all flash chips in an SSD with a single shared external boost converter.<ref>{{Citation |first1=Tadashi |title=Proceedings of the 14th ACM/IEEE international symposium on Low power electronics and design - ISLPED '09 |last1=Yasufuku |first2=Koichi |last2=Ishida |first3=Shinji |last3=Miyamoto |first4=Hiroto |last4=Nakai |first5=Makoto |last5=Takamiya |first6=Takayasu |last6=Sakurai |first7=Ken |last7=Takeuchi |journal=IEICE Transactions on Electronics |url=http://www.computer.org/csdl/proceedings/islped/2009/8684/00/86840087-abs.html |pages=87–92 |year=2009 |volume=93 |issue=3 |url-status=live |archive-url=https://web.archive.org/web/20160305135918/https://www.computer.org/csdl/proceedings/islped/2009/8684/00/86840087-abs.html |archive-date=5 March 2016|doi=10.1145/1594233.1594253 |isbn=9781605586847 |s2cid=6055676 |url-access=subscription |bibcode=2010IEITE..93..317Y}}</ref><ref>{{citation |first1=Rino |last1=Micheloni |first2=Alessia |last2=Marelli |first3=Kam |last3=Eshghi |url=https://books.google.com/books?id=8LS3egzcBG4C&pg=PA188 |title=Inside Solid State Drives (SSDs) |year=2012 |publisher=Springer |url-status=live |archive-url=https://web.archive.org/web/20170209234319/https://books.google.com/books?id=8LS3egzcBG4C&pg=PA188&lpg=PA188 |archive-date=9 February 2017|isbn=9789400751460 |bibcode=2013issd.book.....M }}</ref><ref>{{citation |first1=Rino |last1=Micheloni |first2=Luca |last2=Crippa |url=https://books.google.com/books?id=vaq11vKwo_kC&pg=PA530 |title=Inside NAND Flash Memories |year=2010 |publisher=Springer |url-status=live |archive-url=https://web.archive.org/web/20170209164808/https://books.google.com/books?id=vaq11vKwo_kC&pg=PA530&lpg=PA530 |archive-date=9 February 2017|isbn=9789048194315 }} In particular, {{cite book |doi=10.1007/978-90-481-9431-5_18 |chapter=Low power 3D-integrated SSD |title=Inside NAND Flash Memories |date=2010 |last1=Takeuchi |first1=K. |pages=515–536 |isbn=978-90-481-9430-8 }}</ref><ref>{{citation |first1=Tracey |last1=Mozel |url=https://books.google.com/books?id=XlbOf-m8fdYC&pg=RA5-PA3 |title=CMOSET Fall 2009 Circuits and Memories Track Presentation Slides |year=2009 |publisher=CMOS Emerging Technologies |url-status=live |archive-url=https://web.archive.org/web/20170209213305/https://books.google.com/books?id=XlbOf-m8fdYC&pg=RA5-PA3&lpg=RA5-PA3 |archive-date=9 February 2017|isbn=9781927500217 }}</ref><ref name="ieice-transactions-2010">{{Cite journal |last1=Yasufuku |first1=Tadashi |last2=Ishida |first2=Koichi |last3=Miyamoto |first3=Shinji |last4=Nakai |first4=Hiroto |last5=Takamiya |first5=Makoto |last6=Sakurai |first6=Takayasu |last7=Takeuchi |first7=Ken |date=March 2010 |title=Inductor and TSV Design of 20-V Boost Converter for Low Power 3D Solid State Drive with NAND Flash Memories |pages=317–323 |url=https://www.researchgate.net/publication/220240029  |url-status=live |journal=IEICE Transactions on Electronics |publisher=[[Institute of Electronics, Information and Communication Engineers|IEICE]] |volume=E93-C |issue=3 |doi=10.1587/transele.E93.C.317 |archive-url=https://web.archive.org/web/20160204025034/https://www.researchgate.net/publication/220240029_Inductor_and_TSV_Design_of_20-V_Boost_Converter_for_Low_Power_3D_Solid_State_Drive_with_NAND_Flash_Memories |archive-date=4 February 2016 |doi-access= |bibcode=2010IEITE..93..317Y |url-access=subscription }}</ref><ref>{{cite web | url=https://ieeexplore.ieee.org/document/5986104 | title=4-times faster rising VPASS (10V), 15% lower power VPGM (20V), wide output voltage range voltage generator system for 4-times faster 3D-integrated solid-state drives | date=June 2011 | pages=200–201 }}</ref><ref name="takeuchi-2010">{{Cite conference |last=Takeuchi |first=Ken |date=May 2010 |title=Low power 3D-integrated Solid-State Drive (SSD) with adaptive voltage generator |conference=IEEE International Memory Workshop (IMW)  |location=Seoul, Korea |doi=10.1109/IMW.2010.5488397 |isbn=978-1-4244-6721-1 |issn=2159-4864 }}</ref><ref name="ieee-3d-integrated-2011">{{Cite journal |last1=Ishida |first1=Koichi |last2=Yasufuku |first2=Tadashi |last3=Miyamoto |first3=Shinji |last4=Nakai |first4=Hiroto |last5=Takamiya |first5=Makoto |last6=Sakurai |first6=Takayasu |last7=Takeuchi |first7=Ken |date=May 2011 |title=1.8 V Low-Transient-Energy Adaptive Program-Voltage Generator Based on Boost Converter for 3D-Integrated NAND Flash SSD |journal=IEEE Journal of Solid-State Circuits |publisher=[[Institute of Electrical and Electronics Engineers]] |volume=46 |issue=6 |pages=1478–1487 |doi=10.1109/JSSC.2011.2131810 |bibcode=2011IJSSC..46.1478I |s2cid=13701601 |issn=1558-173X }}</ref>

In spacecraft and other high-radiation environments, the on-chip charge pump is the first part of the flash chip to fail, although flash memories will continue to work{{snd}} in read-only mode{{snd}} at much higher radiation levels.<ref>A. H. Johnston, [http://trs-new.jpl.nasa.gov/dspace/bitstream/2014/13431/1/01-2369.pdf "Space Radiation Effects in Advanced Flash Memories"] {{webarchive|url=https://web.archive.org/web/20160304220536/http://trs-new.jpl.nasa.gov/dspace/bitstream/2014/13431/1/01-2369.pdf |date=4 March 2016 }}.
NASA Electronic Parts and Packaging Program (NEPP). 2001. "... internal transistors used for the charge pump and erase/write control have much thicker oxides because of the requirement for high voltage. This causes flash devices to be considerably more sensitive to total dose damage compared to other [[ULSI]] technologies. It also implies that write and erase functions will be the first parameters to fail from total dose. ... Flash memories will work at much higher radiation levels in the read mode. ... The charge pumps that are required to generate the high voltage for erasing and writing are usually the most sensitive circuit functions, usually failing below 10 [[kilorad|krad]](SI)."</ref>