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US5621685A Expired / Lapsed US ⏱️ 0.0 years remaining

Programmable power generation circuit for flash EEPROM memory systems

Assignee: SanDisk Technologies LLC
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Filing: 1995-06-07
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Granted: 1997-04-15
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Expires: 2015-06-07
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Abstract

Abstract An flash EEPROM system functioning as a mass storage medium for a host computer includes a controller and at least one flash EEPROM memory module. The flash EEPROM memory module includes at least one flash EEPROM chip having an on-chip programmable power generation circuit including a high voltage generator circuit capable of generating a high voltage Vpp from a logic level voltage Vdd provided to the chip, a serial protocol logic circuit, a data latch, a data bus, a register address decoder, and a multi-voltage generator/regulator. The multi-voltage generator/regulator includes a plurality of registers and provides the programming, reading, and erasing voltages required for proper operation of the flash EEPROM system from digital values stored in the plurality of registers by the controller. The high voltage generator circuit includes both high current and low current charge pump circuits for generating the high voltage Vpp. The high current charge pump circuit is connected to relatively large off-chip charge storage devices, and the low current charge pump circuit is connected to relatively small on-chip charge storage devices. The controller may activate one or the other of the high or low current charge pump circuits through control signals connected to enabling circuitry respectively connected to the high and low current charge pump circuits. Alternatively, the controller may deactivate both the high and low current charge pump circuits and cause the high voltage Vpp to be provided from other circuitry on another flash EEPROM chip in the flash EEPROM module.

Inventors

  • 👤 Raul-Adrian Cernea
  • 👤 Douglas J. Lee
  • 👤 Mehrdad Mofidi
  • 👤 Sanjay Mehrotra

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-11-04 05:41
CPC Classifications
G; G11; G11C; G11C16/00; G11C16/02; G11C16/06; G11C16/30; G11C16/10; G11C16/14; G11C16/16

Claims Analysis

Total Claims: 7
Claim 1
Independent Claim 78 words
In a flash EEPROM memory system including at least one flash EEPROM chip, a charge pump circuit comprising: charge storage means externally coupled to said at least one flash EEPROM chip; and a plurality of transistors formed on said at least one flash EEPROM chip and coupled to said charge storage means such that said plurality of transistors and said charge storage means cooperate to generate from an input voltage, an output voltage greater than said input voltage.
Claim 2
Dependent Claim 78 words
In a flash EEPROM memory system including at least one flash EEPROM chip, a charge pump circuit comprising: charge storage means externally coupled to said at least one flash EEPROM chip; and a plurality of transistors formed on said at least one flash EEPROM chip and coupled to said charge storage means such that said plurality of transistors and said charge storage means cooperate to generate from an input voltage, an output voltage greater than said input voltage.
Claim 3
Dependent Claim 39 words
The charge pump circuit as recited in claim 1, wherein said plurality of transistors and said charge storage means cooperate to generate said output voltage and an output current sufficient to program said at least one flash EEPROM chip.
Claim 4
Dependent Claim 39 words
The charge pump circuit as recited in claim 1, wherein said plurality of transistors and said charge storage means cooperate to generate said output voltage and an output current sufficient to read said at least one flash EEPROM chip.
Claim 5
Dependent Claim 39 words
The charge pump circuit as recited in claim 1, wherein said plurality of transistors and said charge storage means cooperate to generate said output voltage and an output current sufficient to erase said at least one flash EEPROM chip.
Claim 6
Dependent Claim 19 words
The charge pump circuit as recited in claim 1, wherein said charge storage means comprises a plurality of capacitors.
Claim 7
Dependent Claim 35 words
The charge pump circuit as recited in claim 1, wherein said flash EEPROM memory system includes a printed circuit board whereupon said at least one flash EEPROM chip and said charge storage means are mounted.

References Cited (Backward Citations)

US4970692A Cited
US5418752A Cited
US5519654A Cited
US5430859A Cited
US5267218A Cited
US5426391A Cited
US5455794A Cited
US5394027A Cited

USPTO Annuity & Maintenance Windows

Annuity Stage Window Opens Payment Deadline Surcharge Period Until Estimated Fee Status
3.5 Years (Year 4) 2000-04-14 2000-10-14 2001-04-15 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 2004-04-14 2004-10-14 2005-04-15 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 2008-04-14 2008-10-14 2009-04-15 $7700.00 Window Closed / Lapsed

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