| US 7,466,190 B2 | ||
| Charge pump with four-well transistors | ||
| Ravindar M. Lall, Portland, Oreg. (US); Moshe Agam, Portland, Oreg. (US); and Kazi Habib, Portland, Oreg. (US) | ||
| Assigned to Lattice Semiconductor Corporation, Hillsboro, Oreg. (US) | ||
| Filed on Jul. 24, 2006, as Appl. No. 11/492,687. | ||
| Prior Publication US 2008/0018379 A1, Jan. 24, 2008 | ||
| Int. Cl. G05F 1/10 (2006.01); H01L 29/00 (2006.01) | ||
| U.S. Cl. 327—537 [327/536; 257/499] | 2 Claims |
| 1. An integrated circuit having a charge pump with one or more stages connected in series, the charge pump having an input
node for receiving a charge pump input signal and an output node for presenting a charge pump output signal, at least one
stage comprising:
a first branch having a first p-type transistor connected in series with a first n-type transistor at a first node and a first
capacitor connected to the first node; and
a second branch having a second p-type transistor connected in series with a second n-type transistor at a second node and
a second capacitor connected to the second node, wherein:
the gates of the transistors in the first branch are connected to the second node;
the gates of the transistors in the second branch are connected to the first node;
at least one of the transistors is a four-well device;
the first and second p-type transistors are four-well devices;
the first and second n-type transistors are three-well devices;
each four-well p-type transistor comprises:
an n-type first well formed in a p-type substrate;
a p-type second well formed in the n-type first well;
an n-type third well formed in the p-type second well; and
p-type source and drain regions formed in the n-type third well, wherein:
the n-type third well is tied to the p-type source region; and
the n-type first well and the p-type second well are tied to the p-type substrate;
each three-well n-type transistor comprises:
an n-type first well formed in the p-type substrate;
a p-type second well formed in the n-type first well; and
n-type source and drain regions formed in the p-type second well, wherein:
the p-type second well is floated; and
the n-type first well is tied to the p-type substrate.
|