Circuit and method for signal conversion

1. A circuit comprising:

a first transistor having a first main current node coupled to a first node for receiving a first voltage signal, a control node coupled to a second node for receiving a second voltage signal, and a second main current node coupled to an output node of the circuit;

a second transistor having a first main current node coupled to a third node for receiving a third voltage signal, a control node coupled to a fourth node for receiving a fourth voltage signal, and a second main current node coupled to said output node of the circuit; and

circuitry configured to generate said first, second, third and fourth voltage signals based on a pair of differential input signals and to provide said first, second, third and fourth voltage signals to said first, second, third, and fourth nodes, respectively, wherein said first and second voltage signals are both referenced to a first supply voltage terminal and wherein said third and fourth voltage signals are both referenced to a second supply voltage terminal, wherein the pair of differential input signals has a voltage swing that is different from a voltage swing of an output signal generated at the output node of the circuit.

2. The circuit of claim 1 , wherein said circuitry is configured to:

generate said first voltage signal by offsetting a voltage of said first supply voltage terminal by an amount determined by relative levels of first and second differential signals of said pair of differential input signals;

generate said second voltage signal by offsetting a voltage of said first supply voltage terminal by an amount determined by the relative levels of said first and second differential signals;

generate said third voltage signal by offsetting a voltage of said second supply voltage terminal by an amount determined by the relative levels of said first and second differential signals; and

generate said fourth voltage signal by offsetting a voltage of said second supply voltage terminal by an amount determined by the relative levels of said first and second differential signals.

3. The circuit of claim 2 , wherein said circuitry comprises:

a first branch generating said first voltage signal and comprising a third transistor and a first resistor coupled to said first supply voltage terminal and in series with said third transistor controlled by said first differential signal;

a second branch generating said second voltage signal and comprising a fourth transistor and a second resistor coupled to said first supply voltage terminal and in series with said fourth transistor controlled by said second differential signal;

a third branch generating said third voltage signal and comprising a fifth transistor and a third resistor coupled to said second supply voltage and in series with said fifth transistor controlled by said first differential signal; and

a fourth branch generating said fourth voltage signal and comprising a sixth transistor and a fourth resistor coupled to said second supply voltage and in series with said sixth transistor controlled by said second differential signal.

4. The circuit of claim 3 , wherein said circuitry further comprises:

a seventh transistor coupled between said first supply voltage terminal and the control node of said first transistor, a control node of said seventh transistor being coupled to a node between the resistor and fourth transistor of said second branch; and

an eighth transistor coupled between said second supply voltage terminal and the control node of said second transistor, a control node of said eighth transistor being coupled to a node between the resistor and sixth transistor of said fourth branch.

5. The circuit of claim 1 , wherein each differential signal of the pair of differential input signals has a voltage swing of less than 0.6 V.

6. The circuit of claim 1 , wherein each differential signal of the pair of differential input signals has a first voltage swing, and wherein an output signal generated at said output node has a second voltage swing higher than said first voltage swing.

7. The circuit of claim 1 , wherein said circuitry further comprises a ninth transistor having a control node and coupled to said output node.

8. The circuit of claim 7 , wherein said circuitry further comprises a track and hold circuit coupled to said output node and having an input and output, wherein said ninth transistor is coupled between said input and output of the track and hold circuit; and

a capacitor coupled to the output of the track and hold circuit.

9. The circuit of claim 7 , wherein said ninth transistor comprises a MOS transistor.

10. The circuit of claim 1 , wherein said first transistor comprises a p-channel MOS transistor, and said second transistor comprises an n-channel MOS transistor.

11. A method of converting a pair of differential input signals by a circuit, the method comprising:

generating first, second, third and fourth voltage signals based on said pair of differential input signals, wherein said first and second voltage signals are both referenced to a first supply voltage terminal and wherein said third and fourth voltage signals are both referenced to a second supply voltage terminal;

applying said first voltage signal to a first main current node of a first transistor and said second voltage signal to a control node of said first transistor, wherein a second main current node of said first transistor is coupled to an output node of the circuit; and

applying said third voltage signal to a first main current node of a second transistor and a fourth voltage signal to a control node of said second transistor, wherein a second main current node of said second transistor is coupled to said output node of the circuit, and wherein the pair of differential input signals has a voltage swing that is different from a voltage swing of an output signal generated at the output node of the circuit.

12. The method according to claim 11 , comprising generating each differential signal of the pair of differential input signals to have a voltage swing of less than 0.6 V.

13. The method according to claim 1 , comprising generating each differential signal of the pair of differential input signals to have a first voltage swing, and wherein an output signal generated at said output node has a second voltage swing higher than the first voltage swing.

14. A circuit comprising:

an output node;

a first transistor comprising a p-channel MOS transistor having a first main current node coupled to a first node for receiving a first voltage signal, a control node coupled to a second node for receiving a second voltage signal, and a second main current node coupled to said output node;

a second transistor comprising an n-channel MOS transistor having a first main current node coupled to a third node for receiving a third voltage signal, a control node coupled to a fourth node for receiving a fourth voltage signal, and a second main current node coupled to said output node; and

circuitry configured to generate said first, second, third and fourth voltage signals based on a pair of differential input signals and to provide said first, second, third and fourth voltage signals to said first, second, third, and fourth nodes, respectively, wherein said first and second voltage signals are both referenced to a first supply voltage terminal and wherein said third and fourth voltage signals are both referenced to a second supply voltage terminal.