Charge pump device
AssigneeSanyo Electric Co., Ltd.
InventorsSatoru Kaneko, Toshiyuki Ohkoda, Takao Myono
Life of this patent
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Abstract
In a charge pump device, occurrence of a latch up can be prevented and current capacity can be increased. An N-type epitaxial silicon layer is formed on a P-type single crystalline silicon substrate, P-type well regions are formed in the N-type epitaxial silicon layer separated from each other, and P-type lower isolation layers and P-type upper isolation layers are formed between the P-type well regions. Then a charge transfer MOS transistor is formed in each of the P-type well regions. The P-type single crystalline silicon substrate is biased to a ground potential or a negative potential.
Claims8
A charge pump device having a plurality of transistors for charge transfer connected in series and outputting a boosted voltage from a last stage of the plurality of transistors for charge transfer, comprising:
- a single crystalline semiconductor substrate of a first conductivity type;
- an epitaxial semiconductor layer of a second conductivity type epitaxially grown on the single crystalline semiconductor substrate;
- a plurality of well regions of the first conductivity type formed in the epitaxial semiconductor layer and separated from each other;
- and
- an isolation layer of the first conductivity type formed between the well regions of the first conductivity type,
- wherein each of the plurality of transistors for charge transfer is formed in each of the plurality of well regions of the first conductivity type.
Dependencies are inferred from the claim text.