Fpga having low power, fast carry chain
AssigneeSiliconblue Technologies Corporation
InventorsJohn Birkner, Andrew Ka Lab Chan
Life of this patent
Estimating the term…
Abstract
FPGA carry chain that does not exhibit significant leakage current. In particular, the carry chain can be switched on/off when desired. In this manner, carry chains can have their leakage currents substantially disabled when they are not in use, thus saving power. Additionally, a carry chain whose logic is separate from the logic blocks that perform the remaining arithmetic functions, and whose inputs are the input data to be added, rather than data from the logic blocks. Such a configuration reduces latency by allowing the carry chain to operate directly on the input data without need to wait on results from the logic blocks.
Claims16
A field programmable gate array (FPGA), comprising:
- carry logic configured to execute a carry operation, the carry logic further comprising a drain voltage terminal and a ground terminal, and supporting a current flowing through the carry logic from the drain voltage terminal to the ground terminal;
- a switching transistor connected to the ground terminal of the carry logic so as to support flow of the current through the switching transistor;
- and
- a programmable switch connected to a gate terminal of the switching transistor and configured to disable the current by switching off a signal applied to the gate terminal.
A field programmable gate array (FPGA) logic cell, comprising:
- a lookup table having first and second inputs for receiving data, and an output for transmitting a result of an operation performed on the received data;
- and
- carry logic facilitating carry operations for the result, the carry logic having first and second inputs and an output;
- wherein the first and second inputs of the carry logic are connected to, respectively, the first and second inputs of the lookup table.
A field programmable gate array (FPGA) logic cell, comprising:
- a lookup table having inputs for receiving input data and an output for transmitting an output corresponding to the input data;
- and
- carry logic receiving the input data and facilitating determination of the output by executing a carry operation on the input data.
Dependencies are inferred from the claim text.