SPECTRUM SPREAD CLOCK GENERATION CIRCUIT

• Main Authors: OKADA KOJI, IIJIMA MASAO
• Format: Patent
• Language: English
• Published: 18.11.2004
• Edition: 7
• Subjects: AUTOMATIC CONTROL, STARTING, SYNCHRONISATION, OR STABILISATIONOF GENERATORS OF ELECTRONIC OSCILLATIONS OR PULSES; BASIC ELECTRONIC CIRCUITRY; CALCULATING; CODE CONVERSION IN GENERAL; CODING; COMPUTING; COUNTING; DECODING; ELECTRIC DIGITAL DATA PROCESSING; ELECTRICITY; PHYSICS

PROBLEM TO BE SOLVED: To obtain a spectrum spread clock generation circuit in which electromagnetic wave radiation can be reduced much more by a simple structure. SOLUTION: The spectrum spread clock generation circuit is provided with a frequency phase comparator 12 detecting a phase difference between a reference clock CLK and a generation clock CK, a charge pump 13 generating a charge/discharge signal in accordance with the detected phase difference, and a resistor R and a capacitor C which are connected in series between the output of the charge pump and prescribed potential. The circuit is also provided with a loop filter 14 generating a differential voltage signal corresponding to the charging signal, a clock generator 15 generating the generation clock of a frequency corresponding to the differential voltage signal, and a current implantation circuit 31 which is connected to connection nodes of the resistor R and the capacitor C in the loop filter 14 and is charged and discharged, so that a voltage of the capacitor changes at a voltage amplitude smaller than a voltage of the capacitor at a spectrum spread period longer than a period of the generation clock. COPYRIGHT: (C)2005,JPO&NCIPI