US 7,095,262 B2 · High reliability triple redundant latch with integrated testability

Abstract

In a preferred embodiment, the invention provides a circuit and method for a high reliability triple redundant latch with integrated testability. Three settable memory elements set an identical logical value into each settable memory element. After the settable memory elements are set, a voting structure with inputs from the second settable memory element, the third settable memory element and control to the settable memory elements determine the logical value held on the first settable memory element. Data may be scanned into and out of the second settable memory element. Data is propagated through the buffer into the third settable memory element. The third settable memory element may be used to scan data out of the triple redundant latch. The propagation delay through a latch is the only propagation delay of the triple redundant latch.

Claims38

Dependent claims

A triple redundant latch for reducing soft errors comprising:

a) a first settable memory element;
b) a second settable memory element;
c) a third settable memory element;
d) a first voting structure;
e) a first buffer;
f) wherein an identical logic value is set in each settable memory element;
g) wherein inputs to the voting structure are provided by the second settable memory element and the third settable memory element;
h) wherein an output of the first voting structure determines a logical value held on the first settable memory element after the first settable memory element, the second settable memory element, and the third settable memory element are set;
i) wherein the second settable memory element is capable of being set by scan data;
j) wherein the second settable memory element into the buffer is capable of propagating data to a scan output;
k) wherein data is capable of being scanned from the buffer into third settable memory element;
l) wherein data is capable of being scanned out of the third settable memory element;
m) wherein a propagation delay through the first settable memory element is the only propagation delay of the triple redundant latch.

10 more elements

A triple redundant latch for reducing soft errors comprising:

a) a first transfer gate, the first transfer gate having an input, a first control input, a second control input, and an output;
b) a second transfer gate, the second transfer gate having an input, a first control input, a second control input, and an output;
c) a third transfer gate, the third transfer gate having an input, a first control input, a second control input and an output;
d) a fourth transfer gate, the fourth transfer gate having an input a first control input, a second control input and an output;
e) a fifth transfer gate, the fifth transfer gate having an input, a first control input, a second control input and an output;
f) a sixth transfer gate, the sixth transfer gate having an input, a first control input, a second control input and an output;
g) a first latch, the first latch having an input and an output;
h) a second latch, the second latch having an input and an output;
i) a third latch, the third latch having an input and an output;
j) a voting structure, the voting structure having an a first input a second input and an output;
k) a buffer, the buffer having an input and an output;
l) wherein the input of the triple redundant latch is connected to the input of the first transfer gate, the input of the second transfer gate, and the input of the third transfer gate;
m) where in the scan-in input of the triple redundant latch is connected to the input of the fourth transfer gate;
n) wherein the output of the triple redundant latch is connected to the input of the first latch;
o) wherein a first control input of the triple redundant latch is connected to the first control input of the first transfer gate, the first control input of the second transfer gate, the first control input of the third transfer gate, and the second input to the fourth transfer gate;
p) wherein a second control input of the triple redundant latch is connected to the second control input of the first transfer gate, the second control input of the second transfer gate, the second control input of the third transfer gate, and the first input to fourth transfer gate;
q) wherein a first scan control input of the triple redundant latch is connected to the first control input of the fifth transfer gate and the second control input of the sixth transfer gate;
r) wherein a second scan control input of the triple redundant latch is connected to the second control input of the fifth transfer gate and to the first control input of the sixth transfer gate;
s) wherein the output of the first transfer gate is connected to the input of the first latch and the output of the fourth transfer gate;
t) wherein the output of the second transfer gate is connected to the input of the second latch, the output of the fifth transfer gate and the input of the buffer;
u) wherein the output of the third transfer gate is connected to the input of the third latch, the output of the sixth transfer gate, and the scan-out of the triple redundant latch;
v) wherein the output of the second latch is connected to the first input of the voting structure;
w) wherein the output of the third latch is connected to the second input of the voting structure;
x) wherein the output of the voting structure is connected to the input of the fourth transfer gate;
y) wherein the output of the buffer is connected to the input of the sixth transfer gate.

22 more elements

A method of manufacturing a triple redundant latch with improved soft error rate comprising:

a) fabricating a first transfer gate, the first transfer gate having an input, a first control input, a second control input, and an output;
b) fabricating a second transfer gate, the second transfer gate having an input, a first control input, a second control input, and an output;
c) fabricating a third transfer gate, the third transfer gate having an input, a first control input, a second control input and an output;
d) fabricating a fourth transfer gate, the fourth transfer gate having an input, a first control input, a second control input and an output;
e) fabricating a fifth transfer gate, the fifth transfer gate having an input, a first control input, a second control input and an output;
f) fabricating a sixth transfer gate, the sixth transfer gate having an input, a first control input, a second control input and an output;
g) fabricating a first latch, the first latch having an input and an output;
h) fabricating a second latch, the second latch having an input and an output;
i) fabricating a third latch, the third latch having an input and an output;
j) fabricating a voting structure, the voting structure having an a first input, a second input, and an output;
k) fabricating a buffer, the buffer having an input and an output;
l) wherein the input of the triple redundant latch is connected to the input of the first transfer gate, the input of the second transfer gate, and the input of the third transfer gate;
m) where in the scan-in input of the triple redundant latch is connected to the input of the fifth transfer gate;
n) wherein the output of the triple redundant latch is connected to the input of the first latch;
o) wherein a first control input of the triple redundant latch is connected to the first control input of the first transfer gate, the first control input of the second transfer gate, the first control input of the third transfer gate, and the second input to the fourth transfer gate;
p) wherein a second control input of the triple redundant latch is connected to the second control input of the first transfer gate, the second control input of the second transfer gate, the second control input of the third transfer gate, and the first input to fourth transfer gate;
q) wherein a first scan control input of the triple redundant latch is connected to the first control input of the fifth transfer gate and the second control input of the sixth transfer gate;
r) wherein a second scan control input of the triple redundant latch is connected to the second control input of the fifth transfer gate and to the first control input of the sixth transfer gate;
s) wherein the output of the first transfer gate is connected to the input of the first latch and the output of the fourth transfer gate;
t) wherein the output of the second transfer gate is connected to the input of the second latch, the output of the fifth transfer gate and the input of the buffer;
u) wherein the output of the third transfer gate is connected to the input of the third latch, the output of the sixth transfer gate, and the scan-out of the triple redundant latch;
v) wherein the output of the second latch is connected to the first input of the voting structure;
w) wherein the output of the third latch is connected to the second input of the voting structure;
x) wherein the output of the voting structure is connected to the input of the fourth transfer gate;
y) wherein the output of the buffer is connected to the input of the sixth transfer gate.

22 more elements

Dependencies are inferred from the claim text.

High reliability triple redundant latch with integrated testability

Life of this patent

High reliability triple redundant latch with integrated testability

Life of this patent

Abstract

Claims38