| 摘要 |
PURPOSE:To decrease the power consumption, by supplying a power to a virtual synchronism preventing circuit in response to a signal of a virtual synchronism detecting circuit for performing power-down of the virtual synchronism preventing circuit. CONSTITUTION:The virtual synchronism detecting circuit 3 discriminates whether the synchronism in a main synchronism circuit 1 is a true synchronism or a virtual synchronism, and when the virtual synchronism state is detected, a virtual synchronism detecting signal is generated. A switching circuit 5 is turned on with this detecting signal to supply power from a power supply circuit 4 to the virtual synchronism circuit 2. Since the power is supplied only when the virtual synchronism detecting circuit 3 detects the virtual synchronism, power-down is attained. |
