PLL circuit and radio communication terminal apparatus using the same,申请号EP20060017995-传众专利搜索

PLL circuit and radio communication terminal apparatus using the same

申请公布号：EP1758255(A2)

申请号：EP20060017995

申请日期：1999.09.14

申请公布日期：2007.02.28

申请人：

RENESAS ELECTRONICS CORPORATION;TTPCOM LIMITED

发明人：YAMAWAKI, TAIZO;ENDO, TAKEFUMI;WATANABE, KAZUO;HORI, KAZUAKI;HILDERSLEY, JULIAN

分类号：H03L7/10;H04B1/40;H03D13/00;H03L7/00;H03L7/08;H03L7/085;H03L7/093;H03L7/099;H03L7/16;H03L7/18;H04L7/033

主分类号：H03L7/10

摘要：<p>A PLL circuit and a radio communication terminal apparatus using the PLL circuit is provided. In the PLL circuit, the number of n pieces of LPFs which have been required is reduced to only one LPF, so that the PLL circuit can reduce a mounting area and the number of pins, and can simplify its design. The PLL circuit according to the present invention comprises a variable-gain phase comparator 1, a mixer 2, an LPF 3, n pieces of VCOs 4-1 to 4n, n pieces of couplers 5-1 to 5-n, and a control circuit 6 for controlling the on/off of the operation of the VCOs. The variable-gain phase comparator 1 is a phase comparator capable of varying a phase difference gain. By the control circuit 6, the on/off of the operation of the VCOs 4-1 to 4n and one of the VCOs 4-1 to 4-n is operated in accordance with a desired operation frequency band; other VCOs are controlled to an off state. The phase difference conversion gain is varied in accordance with the sensitivity of the VCOs 4-1 to 4-n, and thereby, the number of LPF required for the PLL circuit can be reduced to only one.</p>