SEMICONDUCTOR INTEGRATED CIRCUITS

A novel sourceline voltage compensation circuit for embedded NOR flash memory

Shengbo Zhang1, 2, 3, , Guangjun Yang3, Jian Hu3 and Jun Xiao3

+ Author Affiliations

 Corresponding author: Zhang Shengbo, Email:Baron.Zhang@hhgrace.com

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Abstract: A novel sourceline voltage compensation circuit for program operation in embedded flash memory is presented. With the sourceline voltage compensation circuit, the charge pump can modulate the output voltage according to the number of cells to be programmed with data "0". So the IR drop on the sourceline decoding path is compensated, and a stable sourceline voltage can be obtained. In order to reduce the power dissipation in program operation, a bit-inversion program circuit is adopted. By using the bit-inversion program circuit, the cells programmed to data "0" are limited to half of the bits of a write data word, thus power dissipation in program operation is greatly reduced. A 1.8-V 8×64-kbits embedded NOR flash memory employing the two circuits has been integrated using a GSMC 0.18-μm 4-poly 4-metal CMOS process.

Key words: charge pumpflash memorysourceline voltage compensation circuitsplit-gate flash memory cell



[1]
Strenz R. Embedded flash technologies and their applications: status and outlook. IEEE International Electron Devices Meeting (IEDM), 2011: 941
[2]
Sung H C, Lei T F, Hsu T H, et al. Novel program versus disturb window characterization for split-gate flash cell. IEEE Electron Device Lett, 2005, 26: 194 doi: 10.1109/LED.2004.842643
[3]
Kianian S, Levi A, Lee D, et al. A novel 3 volts-only, small sector erase, high density flash EPROM. Symposium on VLSI Technology, Digest of Technical Papers, 1994: 71
[4]
Yeh B. Single transistor non-volatile electrically alterable semiconductor memory device. USA Patent, No.5029130, 1991
[5]
Baek J M, Chun J H, Kwon K W. A power-efficient voltage upconverter for embedded EEPROM application. IEEE Trans Circuits Syst Ⅱ, Exp Briefs, 2010, 57(6): 435 doi: 10.1109/TCSII.2010.2048351
[6]
Kushnarenko A. Method and apparatus for reducing the number of programmed bits in a memory array. US Patent, No. 2003/0046481 A1, 2003 http://www.freepatentsonline.com/y2003/0046481.html
[7]
Seo M K, Sim S H, Oh M H, et al. A 130-nm 0.9-V 66-MHz 8- Mb (256KX32) local SONOS embedded flash EEPROM. IEEE J Solid-State Circuits, 2005, 40: 877 doi: 10.1109/JSSC.2005.845564
[8]
Seo M K, Lee H S. Circuit and method for controlling boosting voltage. US Patent, No.7120058 B2, 2005 http://www.freepatentsonline.com/y2005/0254304.html
[9]
Lin E, Ly A, Nguyen H Q, et al. Circuit for compensating programming current required, depending upon programming state. US Patent, No. 6853584 B2, 2005 http://www.freepatentsonline.com/y2004/0218422.html
[10]
Se-eun O. Boost voltage generating circuit and method thereof. US Patent, No.7499333 B2, 2009 http://www.freepatentsonline.com/7499333.html
[11]
Krzentz S V. Combined resistance–capacitance ladder voltage divider circuit. US Patent, No. 5796296, 1998 http://www.freepatentsonline.com/5796296.html
Fig. 1.  Common-source flash array using split-gate flash memory cell.

Fig. 2.  Architecture of the bit-inversion program circuit.

Fig. 3.  (a) Current-mode comparator. (b) Translation circuit.

Fig. 4.  A simplified conventional program scheme. If Din is data "0", the selected bit line BL$_{\rm sel}$ is connected to a current mirror circuit, so a fixed program current $I_{\rm prog}$ flows through the selected cell A. If Din is data "1", an inhabited voltage $V_{\rm inh}$ (2.5 V) is connected to the selected bit line BL$_{\rm sel}$ by using a level shift circuit.

Fig. 5.  HVP/VSL value versus the number of data "0" in a conventional scheme.

Fig. 6.  The proposed voltage control circuit.

Fig. 7.  Optical microscope photo of the chip.

Fig. 8.  HVP/VSL value versus the number of data "0" in a conventional scheme.

Table 1.   Operation conditions of the split-gate flash cell.

[1]
Strenz R. Embedded flash technologies and their applications: status and outlook. IEEE International Electron Devices Meeting (IEDM), 2011: 941
[2]
Sung H C, Lei T F, Hsu T H, et al. Novel program versus disturb window characterization for split-gate flash cell. IEEE Electron Device Lett, 2005, 26: 194 doi: 10.1109/LED.2004.842643
[3]
Kianian S, Levi A, Lee D, et al. A novel 3 volts-only, small sector erase, high density flash EPROM. Symposium on VLSI Technology, Digest of Technical Papers, 1994: 71
[4]
Yeh B. Single transistor non-volatile electrically alterable semiconductor memory device. USA Patent, No.5029130, 1991
[5]
Baek J M, Chun J H, Kwon K W. A power-efficient voltage upconverter for embedded EEPROM application. IEEE Trans Circuits Syst Ⅱ, Exp Briefs, 2010, 57(6): 435 doi: 10.1109/TCSII.2010.2048351
[6]
Kushnarenko A. Method and apparatus for reducing the number of programmed bits in a memory array. US Patent, No. 2003/0046481 A1, 2003 http://www.freepatentsonline.com/y2003/0046481.html
[7]
Seo M K, Sim S H, Oh M H, et al. A 130-nm 0.9-V 66-MHz 8- Mb (256KX32) local SONOS embedded flash EEPROM. IEEE J Solid-State Circuits, 2005, 40: 877 doi: 10.1109/JSSC.2005.845564
[8]
Seo M K, Lee H S. Circuit and method for controlling boosting voltage. US Patent, No.7120058 B2, 2005 http://www.freepatentsonline.com/y2005/0254304.html
[9]
Lin E, Ly A, Nguyen H Q, et al. Circuit for compensating programming current required, depending upon programming state. US Patent, No. 6853584 B2, 2005 http://www.freepatentsonline.com/y2004/0218422.html
[10]
Se-eun O. Boost voltage generating circuit and method thereof. US Patent, No.7499333 B2, 2009 http://www.freepatentsonline.com/7499333.html
[11]
Krzentz S V. Combined resistance–capacitance ladder voltage divider circuit. US Patent, No. 5796296, 1998 http://www.freepatentsonline.com/5796296.html
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    Received: 23 November 2013 Revised: 14 February 2014 Online: Published: 01 July 2014

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      Shengbo Zhang, Guangjun Yang, Jian Hu, Jun Xiao. A novel sourceline voltage compensation circuit for embedded NOR flash memory[J]. Journal of Semiconductors, 2014, 35(7): 075007. doi: 10.1088/1674-4926/35/7/075007 S B Zhang, G J Yang, J Hu, J Xiao. A novel sourceline voltage compensation circuit for embedded NOR flash memory[J]. J. Semicond., 2014, 35(7): 075007. doi: 10.1088/1674-4926/35/7/075007.Export: BibTex EndNote
      Citation:
      Shengbo Zhang, Guangjun Yang, Jian Hu, Jun Xiao. A novel sourceline voltage compensation circuit for embedded NOR flash memory[J]. Journal of Semiconductors, 2014, 35(7): 075007. doi: 10.1088/1674-4926/35/7/075007

      S B Zhang, G J Yang, J Hu, J Xiao. A novel sourceline voltage compensation circuit for embedded NOR flash memory[J]. J. Semicond., 2014, 35(7): 075007. doi: 10.1088/1674-4926/35/7/075007.
      Export: BibTex EndNote

      A novel sourceline voltage compensation circuit for embedded NOR flash memory

      doi: 10.1088/1674-4926/35/7/075007
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      • Corresponding author: Zhang Shengbo, Email:Baron.Zhang@hhgrace.com
      • Received Date: 2013-11-23
      • Revised Date: 2014-02-14
      • Published Date: 2014-07-01

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