Adaptive temporal filtering of single event effects

• US 8,058,925 B2
• Filed: 04/24/2009
• Issued: 11/15/2011
• Est. Priority Date: 04/24/2009
• Status: Active Grant

• Current Assignee: The Boeing Co.
• Original Assignee: The Boeing Co.
• Inventors: Rasmussen, Brad J.
• Primary Examiner(s): LE, DINH THANH
• Application Number:
  US12/429,638
• Publication Number:
  US 20100271090A1
• Time in Patent Office: 935 Days
• Field of Search: 327551-559
• US Class Current: 327/551
• CPC Class Codes: H03H 17/0219 Compensation of undesirable effects, e.g. quantisation noise, overflow stability problems H03H17/0461
• CPC Class Codes: H03H 17/0261 Non linear filters
• CPC Class Codes: H03H 17/0294 Variable filters; Programmable filters

Abstract

Technologies are described herein for mitigating the effects of single event effects or upsets on digital semiconductor device data paths and clocks utilizing an adaptive temporal filter. The adaptive temporal filter includes a master delay line and a slave delay line to generate two output clock signals that remain unaffected by variations in process, voltage and temperature (PVT) conditions. The adaptive temporal filter supplies the three independent clock signals having a programmable phase relationship, to a triple voting register structure for storing and outputting an uncorrupted data value using a majority voter.

Claims

1. A method of mitigating radiation induced transient upset effects on digital semiconductor device data paths and clocks, comprising:

receiving an input clock signal at an adaptive temporal filter comprising a master delay line and a slave delay line;

supplying the input clock signal to the master delay line comprising a plurality of master delay elements, and to the slave delay line comprising a plurality of slave delay elements;

creating a variable delay element count signal representing a number of master delay elements of the plurality of master delay elements used to delay the input clock signal by one full period at the master delay line;

creating an adaptive count signal representing a number of slave delay elements of the plurality of slave delay elements to be used to delay the input clock signal by a desired offset using the variable delay element count signal from the master delay line and a desired offset signal representing the desired offset;

receiving the adaptive count signal and the input clock signal at the slave delay line;

delaying the input clock signal by using the number of slave delay elements represented by the adaptive count signal to create an output clock signal; and

outputting the output clock signal, wherein the output clock signal is delayed relative to the input clock signal by the desired offset.

2. The method of claim 1, wherein the creating the adaptive count signal further comprises multiplying the number of master delay elements used to delay the input clock signal by one full period and the desired offset.

3. The method of claim 1, further comprising setting the desired offset signal to represent a maximum pulse width of radiation induced transient upset effects to be filtered.

4. The method of claim 1, further comprising adjusting the variable delay element count signal under different process, voltage and temperature conditions.

5. The method of claim 1, wherein creating the adaptive count signal, further comprises:

supplying the variable delay element count signal and the desired offset signal to a data computation component;

combining the variable delay element count signal and the desired offset signal to generate the adaptive count signal.

6. An adaptive temporal filter system, comprising:

an adaptive temporal filter comprising

a first master delay line and a first slave delay line configured to receive an input clock signal and create a first output clock signal that is delayed relative to the input clock signal by a first desired offset, and

a second master delay line and a second slave delay line configured to receive the input clock signal and to create a second output clock signal that is delayed relative to the input clock signal by a second desired offset; and

a triple voting register structure configured

to receive the input clock signal, the first output clock signal and the second output clock signal from the adaptive temporal filter,

to receive a data input signal representing a data value to be stored in the triple voting register structure,

to store the data value in the triple voting register structure once every full period of the input clock signal, the first output clock signal and the second output clock signal, and

to output the stored data value from a majority voter.

7. The adaptive temporal system of claim 6, further comprising:

a first clock tree configured

to receive the input clock signal from the adaptive temporal filter, and

to supply the input clock signal to a first storage element of the triple voting register;

a second clock tree configured

to receive a first output clock signal from the first slave delay line, and

to supply the first output clock signal to a second storage element of the triple voting register; and

a third clock tree configured

to receive a second output clock signal from the second slave delay line, and

to supply the second output clock signal to a third storage element of the triple voting register.

8. The adaptive temporal filter system of claim 7, wherein the adaptive temporal filter further comprises a multiplexer configured to selectively supply the input clock signal to the first clock tree, the second clock tree and the third clock tree.

9. The adaptive temporal filter system of claim 7, wherein the first storage element, the second storage element and the third storage element are configured to store the data input signal only during a rising edge of the input clock signal, the first output clock signal and the second output clock signal, respectively.

10. The adaptive temporal filter system of claim 6, wherein the desired offset is programmed to a maximum upset pulse width of radiation induced transient upset effects to be filtered.

11. The adaptive temporal filter system of claim 6,

wherein the first master delay line comprises a plurality of master delay elements and the first slave delay line comprises a plurality of slave delay elements,

wherein each master delay element and each slave delay element possesses a variable delay length for varying process, voltage and temperature conditions.

12. The adaptive temporal filter system of claim 11,

wherein the first master delay line is configured

to receive the input clock signal,

to determine a number of master delay elements used to delay the input clock signal by one full period, and

to output a variable delay element count signal representing the number of master delay elements used to delay the input clock signal by one full period;

wherein the adaptive temporal filter further comprises a first data computation component configured

to receive the variable delay element count signal from the master delay line,

to receive a desired offset signal representing a desired offset,

to determine a number of slave delay elements to be used to delay the input clock signal by the desired offset, and

to output an adaptive count signal representing the number of slave delay elements to be used to delay the input clock signal by the desired offset; and

wherein the first slave delay line configured

to receive the adaptive count signal,

to receive the input clock signal,

to delay the input clock signal by the desired offset by using the number of slave delay elements represented by the adaptive count signal to create the output clock signal, and

to output the output clock signal that is delayed relative to the input clock signal by the desired offset.