| US 7,511,554 B2 | ||
| Systems and methods for level shifting using AC coupling | ||
| Masaaki Kaneko, Round Rock, Tex. (US); David W. Boerstler, Round Rock, Tex. (US); Eskinder Hailu, Sunnyvale, Calif. (US); and Jieming Qi, Austin, Tex. (US) | ||
| Assigned to Kabushiki Kaisha Toshiba, Tokyo (Japan); and International Business Machines Corporation, Armonk, N.Y. (US) | ||
| Filed on Jun. 18, 2007, as Appl. No. 11/764,262. | ||
| Prior Publication US 2008/0309395 A1, Dec. 18, 2008 | ||
| Int. Cl. H03L 5/00 (2006.01) | ||
| U.S. Cl. 327—333 [326/63; 326/80] | 11 Claims |
| 5. A level shifter system comprising
a capacitor configured to receive a binary input signal, to decouple AC and DC components of the binary input signal, and
to pass the AC component to an intermediate node;
a voltage divider having first and second resistors connected in series between a supply voltage and ground, wherein the intermediate
node is located between the first and second resistors; and
Duty Cycle Compensation (DCC) circuitry that includes
a first branch comprising the voltage divider, the capacitor, and an inverter;
wherein the inverter is coupled to third and fourth resistors and
wherein the third resistor is coupled between the inverter and the supply voltage and the fourth resistor is coupled between
the inverter and ground;
a second branch of the same construction as the first branch;
wherein both branches are coupled to the inputs of a differential amplifier;
wherein the first branch is coupled to receive the input signal, the second branch is coupled to receive the inverted input
signal, and the differential amplifier output is coupled to an amplifier.
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