Soft error resilient circuit design method and logic cells

• US 9,083,341 B2
• Filed: 12/03/2012
• Issued: 07/14/2015
• Est. Priority Date: 01/17/2008
• Status: Active Grant

• Current Assignee: RCI Europe AB
• Original Assignee: Robust Chip, Inc.
• Inventors: Lilja, Klas Olof
• Primary Examiner(s): Rossoshek, Helen
• Application Number:
  US13/692,800
• Publication Number:
  US 20130162293A1
• Time in Patent Office: 953 Days
• Field of Search: 716/50, 716/55, 716/106, 716/111, 716/119, 716/120, 716/132, 716/136, 716/139, 326/9, 326/10, 326/12
• US Class Current: 1/1
• CPC Class Codes: G06F 30/00 Computer-aided design [CAD]
• CPC Class Codes: G06F 30/392 Floor-planning or layout, e.g. partitioning or placement
• CPC Class Codes: H03K 19/00338 In field effect transistor circuits
• CPC Class Codes: H03K 19/20 characterised by logic function, e.g. AND, OR, NOR, NOT circuits H03K19/003 - H03K19/01 take precedence
• CPC Class Codes: H03K 19/215 using field-effect transistors
• CPC Class Codes: H03K 21/10 comprising logic circuits

Abstract

A method is disclosed for creating a logic integrated circuit cell from an original logic integrated circuit gate. The method includes combining the original logic integrated circuit cell with a second circuit which takes as input a complement of inputs of the original logic integrated circuit cell and provides as output complements of the output of the original logic integrated circuit cell. The method further includes connecting the combined logic integrated circuit cells, where the outputs of the combined integrated circuit cells provide the inputs for other combined circuit cells such that, when the output of the original logic integrated circuit from a first combined logic integrated circuit cell is connected as input to a second combined logic integrated circuit cell, then the output of the second circuit in the first combined logic integrated circuit cell is always also connected to the second combined logic integrated circuit cell serving as the inverse of the input signals that come from the original logic integrated circuit cell.

Claims

1. A computer-implemented method of creating a logic integrated circuit cell from an original logic integrated circuit cell, the method comprising:

combining, by a processor, the original logic integrated circuit cell with a second integrated circuit cell, wherein the inputs of the second integrated circuit cell are the complement of each of the inputs of the original logic integrated circuit cell and the output of the second integrated circuit cell is the complement of the output of the original logic integrated circuit cell;

connecting, by the processor, the combined logic integrated circuit cell, to one or more other combined logic integrated circuit cell, such that the output of the original logic integrated circuit cell from the combined logic integrated circuit cell is connected to the inputs of the one or more other combined logic integrated circuit cells, and the output of the second integrated circuit cell from the combined integrated circuit cell is connected to the inputs of the one or more other combined logic integrated circuit cells as the complement of the output from the original logic integrated circuit cell; and

simplifying, by the processor, the combined logic integrated circuit cell, wherein simplifying the combined logic integrated circuit cell comprises;

disconnecting, by the processor, each circuit node in the combined logic integrated circuit cell, which has a voltage value equal to the complement of one of the inputs to the original logic integrated circuit cell, from the circuit portion that provides the input to each of these circuit nodes; and

connecting, by the processor, the disconnected circuit nodes to an external signal with this voltage value.

2. The method according to claim 1, wherein disconnecting each circuit node in the combined logic integrated circuit cell comprises disconnecting, by the processor, each circuit node in the combined logic integrated circuit cell, which has a voltage value that is equal to the complement of one of the inputs to the original logic integrated circuit cell in all states of the circuit.

3. The method according to claim 1, wherein simplifying the combined logic integrated circuit cell comprises:

disconnecting, by the processor, each circuit node in the combined logic integrated circuit cell, which has a voltage value equal to one of the inputs to the original logic integrated circuit cell, from the circuit portion that provides the input to the circuit node; and

connecting, by the processor, the disconnected circuit nodes to an external signal with this voltage value.

4. The method according to claim 3, wherein disconnecting each circuit node in the combined logic integrated circuit cell comprises disconnecting each circuit node in the combined logic integrated circuit cell, which has a voltage value equal to one of the inputs to the original logic integrated circuit cell in all states of the circuit.

5. The method according to claim 3, wherein simplifying the combined logic integrated circuit cell comprises:

analyzing, by the processor, the such re-connected combined logic integrated circuit cell by applying an error signal to each of the inputs, one at a time, for each valid input combination; and

recording, by the processor, the impact on all output nodes of the combined logic integrated circuit cell.

6. The method according to claim 5, wherein simplifying the combined logic integrated circuit cell comprises reversing, by the processor, the connection and disconnection for each circuit node for which an error signal applied to this circuit node gave an error signal on both an original output and its complement output.

7. The method according to claim 6, wherein simplifying the combined logic integrated circuit cell comprises removing, by the processor, circuit portions that are fully disconnected from the circuit that generates the output signals of the combined logic integrated circuit cell.

8. A semiconductor integrated circuit, implemented by a computer-implemented method of creating a logic integrated circuit cell from an original logic integrated circuit cell, the method comprising:

combining, by a processor, the original logic integrated circuit cell with a second integrated circuit cell, wherein the inputs of the second integrated circuit cell are the complement of each of the inputs of the original logic integrated circuit cell and the output of the second integrated circuit cell is the complement of the output of the original logic integrated circuit cell;

connecting, by the processor, the combined logic integrated circuit cell, to one or more other combined logic integrated circuit cell, such that the output of the original logic integrated circuit cell from the combined logic integrated circuit cell is connected to the inputs of the one or more other combined logic integrated circuit cells, and the output of the second integrated circuit cell from the combined integrated circuit cell is connected to the inputs of the one or more other combined logic integrated circuit cells as the complement of the output from the original logic integrated circuit cell,

wherein the semiconductor integrated circuit, comprises;

a physical arrangement where contact areas of one or more devices have been placed along a line in a substrate, and where n-type contact areas of the combined logic integrated circuit cell, which are connected to an output (q) of the original logic integrated circuit cell (n-q), and connected to an output (qi) of the second integrated circuit cell (n-qi), and p-type contact areas of the combined logic integrated circuit cell, which are connected to q (p-q) and to qi (p-qi), are ordered along the line in the substrate such that in-between an n-q node and a p-qi node there is always at least one n-qi node and/or at least one p-q node, and such that in-between an n-qi node and a p-q node there is always at least one n-q node and/or at least one p-qi node;

wherein the logic integrated circuit cell implements an exclusive OR (XOR) logic function using complementary metal-oxide-semiconductor (CMOS) technology, the logic circuit cell comprising;

eight n-type MOS field-effect-transistors (FET) (MOSFET) devices and eight p-type MOSFET devices;

four input signals a, b, ai, bi, wherein ai is the inverse complement of a, and bi is the inverse complement of b;

a power node (VDD), which is connected to a high voltage for the logic circuit cell and a ground node (GND), which is connected to a low voltage for the logic circuit cell; and

two output nodes, q and qi, wherein qi is the inverse complement of q.

9. The semiconductor integrated circuit of claim 8, wherein the logic circuit cell comprises a connection of devices such that the output node q provides an XOR function of the two inputs a and b, and the output node qi provides a complement of the XOR function (NXOR) on the two inputs ai and bi.

10. The semiconductor integrated circuit of claim 8, wherein the logic circuit cell, comprises:

six internal circuit nodes p1, n1a, n1b, p2a, p2b, n2, connected between the MOSFET devices;

a connection between the eight p-type MOSFET devices, where source, gate, and drain nodes are connected as follows;

(vdd, a, p1), (vdd, b, p1), (p1, ai, q), (p1, bi, q), (vdd, ai, p2a), (vdd, a, p2b), (p2a, bi, qi), (p2b, b, qi); and

a connection between the eight n-type MOSFET devices, where source, gate, and drain nodes are connected as follows;

(gnd, b, n1a), (gnd, bi, n1b), (n1a, a, q), (n1b, ai, q), (gnd, a, n2), (gnd, b, n2), (n2, ai, qi), (n2, bi, qi).

11. The semiconductor integrated circuit of claim 10, wherein the logic circuit cell, comprises another connection between the p-type and n-type MOSFET devices which gives the XOR function on the inputs a and b on node q and the complement of the XOR function on the inputs ai and bi on the node qi.

12. The semiconductor integrated circuit of claim 11, wherein the logic circuit cell, a physical layout arrangement where contact areas of the n-type and the p-type MOSFET devices have been placed along a line in a substrate, and where n-type contact areas, which are connected to an output (q) of an original circuit (n-q), and connected to an output (qi) of a second circuit (n-qi), and p-type contact areas which are connected to q (p-q) and to qi (p-qi) are ordered along the line in the substrate such that in-between an n-q node and a p-qi node, there is always at least one n-qi node and/or at least one p-q node, and that in-between an n-qi node and a p-q node there is always at least one n-q node and/or at least one p-qi node.

13. The semiconductor integrated circuit of claim 11, wherein the logic circuit cell, comprises a physical layout arrangement where the contact areas are ordered along a line in the layout with the following order:

[gnd, n1a, n-q, n1b, gnd, n2, n-qi, n2, gnd, vdd, p2b, p-qi, p2a, vdd, p1, p-q, p1, vdd].