Temperature based filter for an on-chip system clock

• US 20040189355A1
• Filed: 12/02/2003
• Published: 09/30/2004
• Est. Priority Date: 12/02/2002
• Status: Active Grant

• Current Assignee: Memjet Technology Ltd. (Memjet Limited)
• Original Assignee: Silverbrook Research Pty Limited
• Inventors: Walmsley, Simon Robert
• Granted Patent: US 7,573,301 B2
• Time in Patent Office: Days
• US Class Current: 327/138
• CPC Class Codes: B41J 2/04505 aiming at correcting alignment
• CPC Class Codes: B41J 2/04508 aiming at correcting other parameters
• CPC Class Codes: B41J 2/0451 for detecting failure, e.g. clogging, malfunctioning actuator
• CPC Class Codes: B41J 2/04528 aiming at warming up the head
• CPC Class Codes: B41J 2/04541 Specific driving circuit
• CPC Class Codes: B41J 2/04543 Block driving
• CPC Class Codes: B41J 2/04563 detecting head temperature; Ink temperature
• CPC Class Codes: B41J 2/04573 Timing; Delays
• CPC Class Codes: B41J 2/04586 controlling heads of a type not covered by groups B41J2/04575 - B41J2/04585, or of an undefined type
• CPC Class Codes: B41J 2202/20 Modules
• CPC Class Codes: G06F 21/554 involving event detection and direct action
• CPC Class Codes: G06F 21/57 Certifying or maintaining trusted computer platforms, e.g. secure boots or power-downs, version controls, system software checks, secure updates or assessing vulnerabilities
• CPC Class Codes: G06F 21/575 Secure boot
• CPC Class Codes: G06F 21/64 Protecting data integrity, e.g. using checksums, certificates or signatures
• CPC Class Codes: G06F 21/71 to assure secure computing or processing of information
• CPC Class Codes: G06F 21/73 by creating or determining hardware identification, e.g. serial numbers
• CPC Class Codes: G06F 21/74 operating in dual or compartmented mode, i.e. at least one secure mode
• CPC Class Codes: G06F 21/78 to assure secure storage of data address-based protection against unauthorised use of memory G06F12/14; record carriers for use with machines and with at least a part designed to carry digital markings G06K19/00
• CPC Class Codes: H03K 5/1252 Suppression or limitation of noise or interference specially adapted for transmission systems H04B15/00, H04L25/08
• CPC Class Codes: H04N 1/405 Halftoning, i.e. converting the picture signal of a continuous-tone original into a corresponding signal showing only two levels
• CPC Class Codes: Y10S 707/99933 : Query processing, i.e. searching
• CPC Class Codes: Y10S 707/99939 : Privileged access
• CPC Class Codes: Y10T 29/49401 : Fluid pattern dispersing device making, e.g., ink jet

Abstract

An integrated circuit including an on-board system clock, the integrated circuit including a clock filter configured to determine a temperature of the integrated circuit and to alter an output of the system clock based on the temperature.

Claims

1. An integrated circuit including an on-board system clock, the integrated circuit including a clock filter configured to determine a temperature of the integrated circuit and to alter an output of the system clock based on the temperature.

2. An integrated circuit according to claim 1, wherein the clock filter is configured to alter the output of the system clock in the event the temperature is outside a predetermined temperature range.

3. An integrated circuit according to claim 2, wherein altering the output includes preventing the clock signal from reaching one or more logical circuits on the integrated circuit to which it would otherwise be applied.

4. An integrated circuit according to claim 3, wherein the predetermined temperature range is selected such that a temperature-related speed of the system clock output that is not due to the clock filter is within a predetermined frequency range.

5. An integrated circuit according to claim 4, wherein the frequency range is within an operating frequency of some or all of the logic circuitry to which the system clock is supplied.

6. An integrated circuit according to claim 4, wherein the temperature range is bounded at a lower level such that an output of the system clock is prevented from reaching some or all of the logic circuitry prior to race conditions due to low temperature causing unpredictable logical behaviour.