发明名称 |
Oscillator circuit, semiconductor device and semiconductor memory device provided with the oscillator circuit, and control method of the oscillator circuit |
摘要 |
There is provided an oscillator circuit capable of obtaining stable frequency by avoiding output having unstable frequency that is likely to occur to an operation/stop-control-feasible type oscillator circuit when oscillation begins. In such an oscillator circuit, an oscillation permitting signal (EN) sets an oscillator section in oscillation-operable state, whereby a controller section starts operation. The controller section that has stared its operation change an oscillation- frequency control signal (VR) into a signal value corresponding to predetermined oscillation frequency so as to set oscillation frequency at an oscillator section. Further on, the oscillator section outputs an oscillation signal in response to a detection signal (MON) that is outputted after a detector section compares a signal inputted therein with a predetermined signal value and detects that the inputted signal reaches a predetermined signal value. Thereby, transient state of an oscillation-frequency control signal (VR) can be detected. That is, there can be avoided an output of an unstable oscillation signal due to a transient oscillation-frequency control signal (VR).
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申请公布号 |
US7492232(B2) |
申请公布日期 |
2009.02.17 |
申请号 |
US20070802637 |
申请日期 |
2007.05.24 |
申请人 |
FUJITSU MICROELECTRONICS LIMITED |
发明人 |
OGAWA YASUSHIGE;KAWAMOTO SATORU |
分类号 |
H03B1/00;H03B5/00;H03B5/24;H03K3/014;H03K3/03 |
主分类号 |
H03B1/00 |
代理机构 |
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代理人 |
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主权项 |
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地址 |
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