发明名称 |
Voltage-controlled crystal oscillator (VCXO) using MOS varactors coupled to an adjustable frequency-tuning voltage |
摘要 |
A voltage-controlled crystal oscillator (VCXO) has variable load capacitors on the crystal nodes. The variable load capacitors are p-channel or n-channel transistors with their source and drain nodes connected to a crystal node. The gates are driven by an input voltage that is generated from a full-swing control voltage by a voltage conversion circuit. The input voltage has a half-swing of only half of the power-supply voltage, or VDD/2. The input voltage driving n-channel capacitors swings from VDD to VDD/2, which is just above the source voltage of VDD/2 on the crystal node and ensures that the n-channel capacitors remain on for most of the range. A series of resistors can divide the input voltage into a series of differing voltages that drive gates of multiple n-channel capacitors that have their source/drains connected in parallel to the crystal node. Capacitance increases as an n-channel capacitor channel turns on.
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申请公布号 |
US6628175(B1) |
申请公布日期 |
2003.09.30 |
申请号 |
US20020063167 |
申请日期 |
2002.03.27 |
申请人 |
PERICOM SEMICONDUCTOR CORP. |
发明人 |
GUO ZHANGQI;HATTORI HIDE |
分类号 |
H03B1/00;H03B5/36;H03K3/03;H03K3/354;(IPC1-7):H03B5/32 |
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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