Dynamic over-voltage protection scheme for interface circuitry
AssigneeLattice Semiconductor Corporation
InventorsWilliam B. Andrews, Larry R Fenstermaker, John A. Schadt, Mou C. Lin
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Abstract
In one embodiment of the invention, an integrated device has interface circuitry that includes a dynamic monitor that monitors the relative potential between (at least) two different power supplies to enable the device to react to over-voltage conditions such that appropriate selections can be made for which power supplies are selected for different components in the interface circuitry, such as output drivers and input receivers. The dynamic monitor enables over-voltage protection to be automatically implemented before the device has been configured, such as during the device's power-on state.
Claims9
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.
Dependencies are inferred from the claim text.