| US 7,547,995 B1 | ||
| Dynamic over-voltage protection scheme for interface circuitry | ||
| William B. Andrews, Emmaus, Pa. (US); Larry R Fenstermaker, Nazareth, Pa. (US); John A. Schadt, Bethlehem, Pa. (US); and Mou C. Lin, High Ridge, N.J. (US) | ||
| Assigned to Lattice Semiconductor Corporation, Hillsboro, Oreg. (US) | ||
| Filed on Feb. 02, 2006, as Appl. No. 11/345,713. | ||
| Int. Cl. H01H 9/54 (2006.01) | ||
| U.S. Cl. 307—140 [326/62] | 9 Claims |
| 1. An integrated device having an interface circuit comprising:
a monitor adapted to dynamically compare first and second power supplies in order to generate a dynamic control signal; and
at least one switch module adapted to select, based on the dynamic control signal, one of the first and second power supplies
for use in powering at least one input/output (I/O) component of the interface circuit, wherein the monitor comprises:
a bias circuit adapted to generate a reduced switch-point voltage level based on the second power supply;
a dynamic comparator adapted to compare the switch-point voltage level to the first power supply to generate at least one
intermediate control signal indicative of whether the first power supply is greater than the second power supply by a predetermined
amount;
a signal driver adapted to generate an other intermediate control signal based on the at least one intermediate control signal,
wherein the dynamic control signal is generated based on the other intermediate control signal; and
a mux adapted to generate the dynamic control signal based on either the other intermediate control signal or a configuration
setting, wherein:
the mux selects the other intermediate control signal before configuration of the integrated device is complete; and
the mux selects the configuration setting after the configuration of the integrated device is complete.
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