High speed voltage following device for analog-to-digital conversion system
AssigneeST-Ericsson SA
InventorsAndrea Barbieri, Germano Nicollini
Life of this patent
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Abstract
A voltage following device is described, for the driving of a sampling network coupleable to an analog/digital converter, comprising at least one first transistor provided with a first terminal to receive an input signal, and a second terminal to provide an output signal to the sampling network which is representative of the input signal translation of an amount equal to a gate and source voltage of said at least one first transistor. The voltage following device having a driving network of said at least one first transistor to keep said gate and source voltage equal to a shift reference voltage.
Claims22
A voltage following device to drive a sampling network (RCM) coupleable to an analog/digital converter, comprising:
- at least one first transistor provided with a first terminal to receive an input signal, and a second terminal to provide an output signal to the sampling network which is representative of a translation of the input signal of an amount equal to a gate and source voltage of the at least one first transistor;
- and
- a driving network of the at least one first transistor configured to keep the gate and source voltage at a shift voltage.
An analog/digital conversion system, comprising:
- a signal source to provide an input signal (VI);
- a voltage following device operatively associated to the signal source to receive the input signal and to provide an output signal;
- a sampling network operatively associated to the voltage following device;
- and
- an analog/digital converter operatively associated to said sampling network, wherein the voltage following device includes:
- a first transistor provided with a first terminal to receive the input signal, and a second terminal to provide the output signal to the sampling network, the output signal being substantially equal to a sum of the input signal and a shift reference voltage;
- and
- means for maintaining the gate and source voltage of the first transistor substantially at a level of the shift reference voltage.
A method of converting an analog source signal to a digital signal, the method comprising:
- providing the analog source signal to an input of a first transistor;
- maintaining a gate-source voltage of the first transistor at a level of shift-reference voltage, wherein maintaining the gate-source voltage of the first transistor at the level of the shift reference voltage comprises providing the shift reference voltage to an inverting input of an operational amplifier;
- and
- providing an output equal to a sum of the analog source voltage and the shift reference voltage.
Dependencies are inferred from the claim text.