| 摘要 |
PURPOSE: An automatic free charge control device is provided to improve the compatibility between two devices having the different operation frequency of each other by controlling free charge starting timing. CONSTITUTION: An automatic free charge control device includes a frequency dividing unit(100), a frequency comparing unit(200), and a free charge timing control unit(300). The frequency dividing unit(100) performs a frequency division about an external input clock signal(CLK), and generates an internal clock signal(CLK1). The frequency comparing unit(200) receives the internal clock signal(CLK1), and compares delay time and frequency. At this time, the delay time and the frequency are demanded for a write operation. The free charge timing control unit(300) controls the starting timing of an automatic free charge operation by activating the first automatic free charge control(auto_pcg1) and the second automatic free charge control(auto_pcg2) selectively through combining the first automatic free charge control(auto_pcg1) and the second automatic free charge control(auto_pcg2) with an output signal of the frequency comparing unit(200). At this time, the first automatic free charge control(auto_pcg1) and the second automatic free charge control(auto_pcg2) are generated under a control of a burst finish signal(burst), and a timing difference of the first automatic free charge control(auto_pcg1) and the second automatic free charge control(auto_pcg2) is one clock cycle.
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