Plural oscillator circuit arrangement for rapidly resetting a computer circuit

US5196810A · kind A · utility

Assignee

• Robert Bosch GmbH · DE

Inventors

• Guenter Graether · Mühlacker, DE
• Werner Jundt · Ludwigsburg, DE
• Guenther Kaiser · Stuttgart, DE

Key dates

• Filing date: Feb 3, 1992
• Grant date: Mar 23, 1993
• Expiry date: Feb 3, 2012

Classification

• Technology area (CPC G): Physics
• CPC primary: G06F1/24
• WIPO field: Computer technology
• WIPO sector: Electrical engineering

Abstract

A circuit arrangement for providing a frequency for a computer circuit is suggested in which, in adition to a quartz oscillator, an additional oscillator which quickly begins to oscillate is provided. To ensure a quick operation of the computer circuit when switching on the computer circuit or after voltage dips, the oscillator which quickly begins to oscillate is first connected with the computer circuit when voltage is applied, so that the resetting processes can proceed very quickly. If the quartz oscillator has begun to oscillate and has reached a stable operating state, a switching is effected from the oscillator which quickly begins to oscillate to the quartz oscillator which takes over from the latter to continue providing a frequency for the computer circuit. The circuit arrangement can also contain a comparator whose inputs are connected to the respective oscillators and which compares the oscillator frequencies of the output signals from both oscillators. The frequency comparator can be connected to a switch which connects one or the other of the oscillators to the input of the computer circuit according to the comparison of oscillator frequencies in the comparator.