| 摘要 |
<P>PROBLEM TO BE SOLVED: To solve the following problem: a duty cannot be accurately detected by a conventional duty detection circuit because a charge/discharge operation after precharge of a capacitor is different from the charge/discharge operation during a usual duty detection operation. <P>SOLUTION: The semiconductor device includes: a storage unit (capacitors C1 and C2) for integrating a ratio (duty ratio) of a period in which an internal clock signal CLK takes a high level and a period in which it takes a low level and electrically storing it; an integration operation control circuit 42 for controlling an integration operation (duty detection operation) in the storage unit (capacitors C1 and C2); a constant current circuit (bias transistors BTr1 and BTr2) in which one end is connected to the integration operation control circuit 42 and the other end is connected to a power line (VDD, GND); and a precharge circuit 43 for initializing an integration result. The semiconductor device is configured so as to cause a current to flow in the current circuit (bias transistors BTr1 and BTr2) during the initialization performed by the precharge circuit 43. <P>COPYRIGHT: (C)2010,JPO&INPIT |
