| 摘要 |
PROBLEM TO BE SOLVED: To suppress power supply noise by supplying an integrated circuit, at a predetermined time with a quantity of charge determined in accordance with the quantity of power supply noise. SOLUTION: A noise reduction circuit 101 has a plurality of charge supply circuits 105-108 for supplying charges to VDD. When operation of an integrated circuit 102 due to deficiency in the quantity of a charge Q of VDD and a power supply noise of -ΔVDD is generated, a charge quantity determining circuit 104 determines the combination of charge supply circuits 105-108 sufficient for supplying the VDD with the quantity of the charge Q and delivers a control signal to the noise reduction circuit 101. A phase adjustment circuit 103 synchronizes the time, to the time when the noise reduction circuit 101 supplies the quantity of charge Q to the VDD with the generating time of noise -ΔVDD. A noise +ΔVDD is generated by the charge Q which is outputted from the noise reduction circuit, and cancels the power supply noise of -ΔVDD.
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