Temperature based filter for an on-chip system clock

• US 7,573,301 B2
• Filed: 12/02/2003
• Issued: 08/11/2009
• Est. Priority Date: 12/02/2002
• Status: Expired due to Fees

• Current Assignee: Memjet Technology Ltd. (Memjet Limited)
• Original Assignee: Silverbrook Research Pty Limited
• Inventors: Walmsley, Simon Robert
• Primary Examiner(s): LE, DINH THANH
• Application Number:
  US10/727,198
• Publication Number:
  US 20040189355A1
• Time in Patent Office: 2,079 Days
• Field of Search: 327512-513, 327551-559, 327/291, 327/299, 327/34, 327/138
• US Class Current: 327/34
• 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 comprising a clock filter coupled between said on-board system clock and a logic circuitry and having a temperature sensor which is configured to detect under and over temperature conditions of the integrated circuit, the under temperature condition being that at which the temperature is below a predetermined temperature and the over temperature condition being that at which the temperature is above the predetermined temperature, and to cause said clock filter to block the on-board system clock from reaching to the logic circuitry of the integrated circuit in the event that either of the under and over temperature conditions are detected.

2. An integrated circuit according to claim 1, wherein the predetermined temperature is selected such that a temperature-related frequency of the system clock output that is not due to the clock filter is within a predetermined frequency range.

3. An integrated circuit according to claim 2, wherein the predetermined frequency range is within an operating frequency of the logic circuitry to which the system clock is supplied.

4. An integrated circuit according to claim 2, wherein the predetermined temperature is such that an output of the system clock is prevented from reaching the logic circuitry prior to race conditions due to low temperature.