Systems and methods for common mode level shifting
AssigneeQUALCOMM Incorporated
InventorsMiao Li, Xiaohua Kong, Zhi Zhu, Jie Xu
Life of this patent
Estimating the term…
Abstract
A common mode voltage level shifting circuit including: input nodes configured to receive a differential signal with a first common mode voltage, a pair of shunt capacitors coupled between the input nodes and a corresponding pair of output nodes, a threshold voltage circuit, including the output nodes, coupled to the differential signal though the shunt capacitors, the threshold voltage circuit configured to provide a second common mode voltage for the differential signal at the output nodes, and current sources that are controlled according to a level of the first common mode voltage, the current sources coupled to the output nodes to effect the second common mode voltage.
Claims30
A common mode voltage level shifting circuit, comprising:
- input nodes configured to receive a differential signal with a first common mode voltage;
- a pair of shunt capacitors coupled between the input nodes and a corresponding pair of output nodes;
- a threshold voltage circuit, including the output nodes, coupled to the differential signal though the shunt capacitors, the threshold voltage circuit configured to provide a second common mode voltage for the differential signal at the output nodes;
- and
- current sources that are controlled according to a level of the first common mode voltage, the current sources coupled to the output nodes to effect the second common mode voltage.
A method for shifting a common mode voltage level, the method comprising:
- receiving a differential signal with a first common mode voltage level;
- coupling the differential signal to a pair of output nodes through a pair of shunt capacitors;
- generating a current that is controlled by the first common mode voltage level;
- and
- mirroring the current through the output nodes to generate a second common mode voltage level at the output nodes.
A common mode voltage level shifting circuit, comprising:
- input nodes configured to receive a differential signal with a first common mode voltage;
- a pair of shunt capacitors coupling the differential signal to output nodes of the circuit;
- a threshold voltage circuit, including the output nodes, configured to receive the differential signal though the shunt capacitors, the threshold voltage circuit configured to provide a second common mode voltage for the differential signal at the output nodes;
- and
- means for driving the output nodes to effect the second common mode voltage, the driving means being controlled according to a level of the first common mode voltage.
A data receiver circuit comprising:
- first circuitry configured to receive a differential signal having a first common mode voltage level;
- a level-shifting component coupled to the first circuitry, the level shifting component including:
- a current source configured to produce a current inversely related to the first common mode voltage and configured to drive the current to output nodes of the level-shifting component, a pair of shunt capacitors coupling the differential signal to the output nodes, a pair of transistors in communication with the shunt capacitors, each of the transistors configured to receive a respective component of the differential signal and current from the current source, wherein respective voltage drops at each of the transistors defines a second common mode voltage level;
- and
- second circuitry in communication with the output nodes of the level shifting component, the second circuitry configured to receive a modified version of the differential signal at the second common mode voltage level.
Dependencies are inferred from the claim text.