| 摘要 |
PURPOSE:To control a current flowing in a memory cell, by providing a frequency detection circuit between a signal input terminal and a current control circuit for a current flowing the memory cell, detecting the frequency of an input signal, and inputting the output to a current control circuit. CONSTITUTION:A frequency detection circuit having a buffer circuit BUF, differentiating circuit DIF and rectification and smoothing circuit SM is provided between a signal input terminal IN and a current control circuit CCT. A base potential of transistors Q30-Q3n constituting each constant current source of memory is supplied from a current control circuit CCT, and when the frequency of an input signal is high, i.e., the frequency of access is high, the output voltage of the current control circuit is high and the frequency of input signal is low. That is, when the frequency of access is low, the output voltage is low and the holding current in the memory is controlled with the frequency of access. Thus, the power can be used efficiently and the power consumption is decreased. |
