Lsi Logic Corporation

Ravindra U Shenoy

Xiaomin Si

Lapoe E Lynn

Tzu-Wang Pan

An apparatus comprising a first circuit, a second circuit and a third circuit. The first circuit may be configured to generate an upconverted signal in response to an input signal and a first oscillation signal. The second circuit may be configured to generate a downconverted signal in response to the upconverted signal and as second oscillation signal. The third circuit may be configured to generate an output signal in response to the downconverted signal and a third oscillation signal derived from the second oscillation signal. The upconverting and downconverting may filter undesired channels from the output signal.

Triple conversion RF tuner with synchronous local oscillators

An initial phase control for an oscillator such as a differential ring voltage-controlled oscillator is disclosed. The initial phase control generally comprises a current source circuit coupled to a first node of the delay cell and a current provider. The current source circuit and current provider are preferably selectively and synchronously in an on or off state such that when the current source circuit and current provider are in an on state, the current source circuit draws a current through the first node of the delay cell and the current provider provides current through a second node of the delay cell. A method for controlling a delay cell and an initial phase control for a differential ring oscillator having a plurality of delay cells in a ring configuration are also disclosed.

Initial phase control of an oscillator

A delay cell, a method for generating a delay, and a differential ring oscillator are disclosed. The delay cell provides a stable delay with a low voltage power supply, and has a high power supply rejection ratio. The delay cell generally comprises a first and second input receiver on a first and second branch, respectively, to receive an input to control a current on each branch, each branch includes an output node capacitively coupled to a power supply. Each branch may include a current source coupled between the output node and the power supply and/or a lower limit clamp coupled between the output node and the power supply to maintain an output at the output node above a lower limit. The delay cell may also include a first and a second current diverter coupled to the first and second branch for diverting current on the first and second branch away from the first and second input receiver, respectively. An upper limit clamp may be coupled between the power supply and the first and second current diverters to maintain the output below an upper limit. Inputs to the lower and upper limit clamps may be generated relative to the power supply. The delay cell may further include a tail current source coupled between ground and the input receivers and an upper clamp current source coupled between ground and the first and second current diverters.

Double-clamped delay stage and voltage controlled oscillator

A system and method for a supply-independent VCO biasing scheme for generating bias voltages and currents for a VCO of a phase-locked loop are disclosed A biasing scheme for generating a bias electrical signal comprises a first and second current source coupled to a power supply, a current drain coupled to the second current source and to ground, a replica device having a first node, a second node coupled to the second current source and the current drain, and a third node coupled to ground, and a first and second current splitting device having first nodes coupled to each other and to the current source and having third nodes coupled to the first and second nodes of the replica device, respectively.

Supply independent biasing scheme

A system and method for a differential charge pump with reduced charge-coupling effects for use in integrated circuits such as a phase-lock loop are disclosed. The charge pump includes a first branch, a second branch, and a charge device. The first branch includes a first current source and sink coupled to a power supply and ground, respectively, a first current steering device coupled between the first current source and sink, and a first buffer coupled to the first current steering device between a first charge node and a first damp node. The second branch includes a second current source and sink coupled to a power supply and ground, respectively, a second current steering device coupled between the second current source and sink, and a second buffer coupled to the second current steering device between a second charge node and a second damp node. The charge device is coupled between the first buffer and the second buffer at the first and second charge nodes, the first and second buffers being adapted to vary voltages at the first and second damp nodes relative to voltages at the first and second charge nodes, respectively. Each of the current steering devices is adapted to selectively steer current from one of the first and second current sources through the charge device to one of the first and second current sinks.

Growing community of inventors

Sunnyvale, CA, United States of America

Ravindra U Shenoy