SWITCHING NOISE REDUCING CIRCUIT

• Main Authors: KAIZU KATSUMI, KOIKE SHINJI
• Format: Patent
• Language: English
• Published: 11.09.1998
• Edition: 6
• Subjects: BASIC ELECTRONIC CIRCUITRY; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR; ELECTRICITY; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS; PRINTED CIRCUITS; PULSE TECHNIQUE

PROBLEM TO BE SOLVED: To reduce switching noise when high-speed logic elements are integrated to high density by performing a pair terminating process by the terminating resistor of the input signal wires of a logic element on a printed circuit board and the terminating resistor of an inverted output signal wires from which a logic-inverted signal is outputted. SOLUTION: When switches 51 to 54 are all open, input terminals of logic elements 21 to 24 are fixed at a level L. Input terminals 71 to 74 are always open, so the input terminals of the logic circuits 21 to 24 are always fixed at the level L. When the switches 51 to 54 are all turned on, the input terminals go up to the level H, so signal output terminals 41 to 44 connected to OR logic output terminals of the logic elements 21 to 24 are fixed at the level H. Therefore, NOR logic output terminals are fixed at the level L, so a current flows to none of the terminating resistors 11 to 14. This results from the noise cancellation effect by the operation of balanced termination on the input/output sides of the logic elements.