公开(公告)号：US5847614A

公开(公告)日：1998-12-08

申请号：US751224

申请日：1996-11-15

申请人： Barrie Gilbert ,  Daryl Carbonari ,  Eberhard Brunner ,  Fred Weiss

发明人： Barrie Gilbert ,  Daryl Carbonari ,  Eberhard Brunner ,  Fred Weiss

IPC分类号： H03L7/08 ,  H03L7/089 ,  H03L7/14 ,  H03L7/18 ,  H03L7/093

CPC分类号： H03L7/18 ,  H03L7/0891 ,  H03L7/0896 ,  H03L7/14 ,  H03L7/0802

摘要： A charge pump in a phase locked loop is enabled only when a loop filter needs to be updated, thereby reducing the power consumption of the charge pump. The charge pump is enabled or disabled in response to an enable signal which is generated by a latch. The enable signal is activated by look-ahead signals which are activated in advance of either a pulse from a reference signal or a pulse from a variable signal so as to allow the charge pump to stabilize before providing the charge current to update the loop filter. Logic signals from a programmable divider and reference signal generator are used to generate the look-ahead signals. The charge pump is disabled by a reset signal from a phase-frequency detector after the loop filter is updated. The charge pump includes a current switch for generating source and sink charge currents in response to pump-up and pump-down control signals. A bias cell provides two reference signals to the current switch. The reference signals are disabled in response to an enable signal, thereby disabling the current switch and reducing the power consumption of the charge pump.

摘要翻译： 只有在需要更新环路滤波器时才能启用锁相环中的电荷泵，从而降低电荷泵的功耗。 响应于由锁存器产生的使能信号，电荷泵被使能或禁止。 使能信号由先前信号激活，该信号在来自参考信号的脉冲或来自可变信号的脉冲之前被激活，以便在提供充电电流以更新环路滤波器之前允许电荷泵稳定。 来自可编程分频器和参考信号发生器的逻辑信号用于产生先行信号。 在更新环路滤波器之后，电荷泵由相位频率检测器的复位信号禁止。 电荷泵包括电流开关，用于响应于泵浦和抽吸控制信号产生源极和吸收器充电电流。 偏置单元为电流开关提供两个参考信号。 参考信号响应于使能信号被禁用，从而禁用电流开关并降低电荷泵的功率消耗。