公开(公告)号：US09541939B2

公开(公告)日：2017-01-10

申请号：US14291463

申请日：2014-05-30

Applicant: MediaTek Inc.

Inventor： Liang-Ting Kuo ,  Wei-Hao Chiu

IPC: G05F3/02 ,  H03K17/30 ,  H03K19/00 ,  G05F3/26

CPC classification number: G05F3/02 ,  G05F3/26 ,  H03K17/302 ,  H03K19/0027

Abstract: A switching current source circuit is provided. A current source drains a bias current from a power supply via a first mirror transistor. A second mirror transistor has a source coupled to the power supply, a gate coupled to the gate of the first mirror transistor, and a drain for providing an output current. A switch is coupled between the gates of the first and second mirror transistors, and has a control terminal for receiving a control signal. A first capacitor is coupled between the gate of the second mirror transistor and the voltage generating unit. A second capacitor is coupled between the gate of the second mirror transistor and a ground. The voltage generating unit selectively provides a first voltage or a second voltage different from the first voltage to the first capacitor according to the control signal.

Abstract translation: 提供开关电流源电路。 电流源经由第一反射镜晶体管从电源漏出偏置电流。 第二反射镜晶体管具有耦合到电源的源极，耦合到第一反射镜晶体管的栅极的栅极和用于提供输出电流的漏极。 开关耦合在第一和第二反射镜晶体管的栅极之间，并且具有用于接收控制信号的控制端子。 第一电容器耦合在第二反射镜晶体管的栅极和电压产生单元之间。 第二电容器耦合在第二反射镜晶体管的栅极和地之间。 电压产生单元根据控制信号向第一电容器选择性地提供不同于第一电压的第一电压或第二电压。