Qualcomm Incorporated

Jie Xu

Xiaohua Kong

Miao Li

Madjid Hafizi

Zhi Zhu

Nam Dang

Yu Song

Li Hsiang Sun

Li Sun

A data transmitter includes: a plurality of parallel driver slices, a first slice of the plurality of parallel driver slices having a first signal generator circuit with a first transistor coupled to a data signal and in series with a second transistor coupled to a first bias signal; and a first bias circuit including a third transistor and a fourth transistor in series with a first current source, the first bias circuit further including a first operational amplifier (op amp) having a first input coupled to a first reference voltage and a second input coupled between the fourth transistor and the first current source, an output of the first op amp configured to provide the first bias signal to the second transistor and to the third transistor.

Calibrating resistance for data drivers

Certain aspects of the present disclosure generally relate to a driver circuit for a serializer/deserializer (SerDes) transmitter and techniques for operating such a driver circuit. One example driver circuit generally includes a pre-driver circuit, an output stage circuit, and a common-gate buffer circuit coupled between an output of the pre-driver circuit and a first input of the output stage circuit.

SerDes driver with common-gate-based buffer to use core devices in relatively high power supply domain

A pre-driver circuit generates a driver bias signal based on a swing command, a driver impedance characteristic, and an input signal. A driver receives the driver bias signal and generates, in response, a driver signal having a swing and having an output impedance corresponding to the bias signal. Optionally, the driver receives power from a switchable one of multiple supply rails, according to the swing. Optionally, the driver has voltage controlled resistor elements and the driver bias signal is generated based on the swing command and a replica of the driver voltage controlled resistor elements.

Multi-standard, automatic impedance controlled driver with supply regulation

A plurality of drivers for driving corresponding differential data output signals are arranged in series such that a first current discharged by a first one of the drivers is recycled through remaining ones of the drivers.

Voltage mode driver with charge recycling

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.

Systems and methods for common mode level shifting

Systems and methods for decoding pulse-width modulated (PWM) data are disclosed. An example decoder filters a data input signal with a one-sided pulse filter. The one-sided pulse filter suppresses short pulses on the data input signal and passes long pulses. The example decoder latch the filtered data signal at the end of each bit time of the data input signal. The duration of pulses that are suppressed by the one-sided pulse filter can be calibrated to compensate for circuit variations and to allow the decoder to operate at various data rates. The decoder can be implemented in a small integrated circuit area and can be power efficient.

Pulse-width modulation data decoder

A population of drivers is provided in parallel to a driver output and a population of pre-emphasis path drivers is provided in parallel to the driver output. The population of drivers is updated and the population of pre-emphasis path drivers is updated in an inverse relation to the updating of the population of pre-emphasis path drivers. Optionally, the population of drivers has an initial value of n and the population of pre-emphasis path drivers has an initial value of m, and the sum of n and m is P. Optionally, the updated population of n is n' and the updated population of m is m&#x2032;, and n&#x2032; is approximately equal to P&#x2212;m&#x2032;.

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San Diego, CA, United States of America

Jie Xu