Title: Power supply voltage control apparatus
Application Number: 200610137500 Application Date: 2006.10.26
Publication Number: 1956308 Publication Date: 2007.05.02
Approval Pub. Date: Granted Pub. Date:
International Classifi-cation: H02M3/155;H03K19/00;H03L7/06
Applicant(s) Name: Matsushita Electric Ind Co., Ltd. Address:
Inventor(s) Name: Ito Minoru
Attorney & Agent: shaoya li lixiao shu
Abstract:
    A power supply voltage control apparatus capable of freely setting a clock period setting margin according to a system clock frequency, and capable of converging power supply voltage to minimum power supply voltage where normal operation is possible in a short period of time without errors in operation of internal circuits in response to changes in the system clock frequency is provided. Power supply voltage control apparatus 100 is provided with frequency-dividing circuit 121 that frequency-divides the system clock at frequency-dividing ratio 1 , frequency-dividing circuit 122 that frequency-divides the output of voltage control oscillator circuit 110 at frequency-dividing ratio 2 , phase comparator/frequency comparator 130 that carries out phase comparison/frequency comparison on the respective output signals of frequency-dividing circuits 121 and 122 , and memory 142 in controller 145. Frequency-dividing ratios of frequency-dividing circuits 121 and 122 are set by control circuit 141 according to an operation mode signal corresponding to the system clock frequency. When the system clock frequency changes, the preset values of the controller 145 perform the initial setting of the up/down counter 143 and the setting of the register 144.
Time: 4
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