发明名称 |
Circuit for measuring absolute spread in capacitors implemented in planary technology |
摘要 |
A circuit for measuring absolute spread in capacitors implemented in planary technology. A charge pump supplying a charge current to an internal capacitor (Cint) is used, the voltage across the internal capacitor (Cint) being coupled through a comparator for comparing the voltage with first and second threshold levels. A bistable multivibrator reverses the direction of the charge current, to charge the internal capacitor (Cint) when the voltage decreases below the second threshold level, and to decharge the internal capacitor (Cint) when the voltage increases above the first threshold level. The charge current is determined by a reference voltage that is provided across an external resistor (Rext), the first and second threshold levels defining a voltage range being proportional to the reference voltage. An output signal of the bistable multivibrator is coupled to frequency measuring means to compare the repetition frequency thereof with a reference frequency.
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申请公布号 |
US2004090237(A1) |
申请公布日期 |
2004.05.13 |
申请号 |
US20020296292 |
申请日期 |
2002.11.21 |
申请人 |
KASPERKOVITZ WOLFDIETRICH GEORG |
发明人 |
KASPERKOVITZ WOLFDIETRICH GEORG |
分类号 |
G01R27/26;G01R31/28;(IPC1-7):G01R27/26;G01R31/12 |
主分类号 |
G01R27/26 |
代理机构 |
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主权项 |
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