Field-programmable device with buffer between programmable circuit
First Claim
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1. A field-programmble device in which there are:
- first and second circuits, each having at least one field-programmable element;
first and second lines respectively connected to the first and second circuits;
means for coupling the first and second lines;
a first current supply for providing the first line with current adequate for normal operation of the device but insufficient to enable any of the field-programmable elements to be programmed; and
select means for providing the first line with current that reaches a level sufficient tb enable each field-programmable element in the first circuit to be programmed during a programming period;
characterized in that the coupling means comprises;
a second current supply for providing current at a node;
a first rectifier coupled between the first line and the node;
a second rectifier coupled between the node and the first line in the opposite forward conductive direction to the first rectifier;
an amplifier having a first flow electrode, a second flow electrode, and a control electrode for controlling current transmission between the flow electrodes, the control electrode coupled to the node, the second electrode coupled to the second line; and
supply means for providing the first electrode with current which is normally insufficient to enable any of the field-programmable elements to be programmed but which, in conjunction with the current from the select means, reaches a level sufficient to enable each field-programmable element in the second circuit to be programmed during a programming period.
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Abstract
A field-programmable device contains a buffer (20) located between a pair of programmable circuits (14 and 16) along a column (10) connecting the circuits. The buffer provides increased current to the column portion connected to one of the circuits (16) without increasing the current supply requirements for the column portion connected to the other circuit (14). This permits the device to switch faster and/or to accommodate programmable circuits of large size. The buffer also enables the same select circuitry to be used in programming both circuits without causing a significant voltage between them during normal operation.
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Citations
17 Claims
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1. A field-programmble device in which there are:
- first and second circuits, each having at least one field-programmable element;
first and second lines respectively connected to the first and second circuits;
means for coupling the first and second lines;
a first current supply for providing the first line with current adequate for normal operation of the device but insufficient to enable any of the field-programmable elements to be programmed; and
select means for providing the first line with current that reaches a level sufficient tb enable each field-programmable element in the first circuit to be programmed during a programming period;
characterized in that the coupling means comprises;a second current supply for providing current at a node; a first rectifier coupled between the first line and the node; a second rectifier coupled between the node and the first line in the opposite forward conductive direction to the first rectifier; an amplifier having a first flow electrode, a second flow electrode, and a control electrode for controlling current transmission between the flow electrodes, the control electrode coupled to the node, the second electrode coupled to the second line; and supply means for providing the first electrode with current which is normally insufficient to enable any of the field-programmable elements to be programmed but which, in conjunction with the current from the select means, reaches a level sufficient to enable each field-programmable element in the second circuit to be programmed during a programming period. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17)
- first and second circuits, each having at least one field-programmable element;
Specification