Driver circuit for transmitter
A driver circuit includes a first inverter, a bias-control circuit, and a second inverter. The first inverter, which is connected between a first supply voltage and ground, receives an input data signal and generates an inverted version of the input data signal. The bias-control circuit, which is connected between a second supply voltage and the first inverter, receives the inverted version of the input data signal and a bias signal, and generates a level-shifted data signal based on the inverted version of the input data signal, the bias signal, and the second supply voltage. The bias-control circuit reduces a difference between voltage levels of the second supply voltage and the inverted version of the input data signal. The second inverter is connected between the second supply voltage and ground, and further connected to the bias-control circuit and first inverter and generates an output data signal.
1. A driver circuit, comprising:
a first inverter, connected between a first supply voltage and ground, that receives an input data signal and generates an inverted version of the input data signal;
a bias-control circuit, connected between a second supply voltage and the first inverter, that receives the inverted version of the input data signal and a bias signal and generates a level-shifted data signal based on the inverted version of the input data signal, the bias signal, and the second supply voltage, wherein the bias-control circuit reduces a difference between voltage levels of the second supply voltage and the inverted version of the input data signal, and a voltage level of the bias signal is equal to a difference between a voltage level of the second supply voltage and half of a voltage level of the first supply voltage; and
a second inverter, connected between the second supply voltage and the ground, that is connected to the bias-control circuit and the first inverter for receiving the level-shifted data signal and the inverted version of the input data signal, respectively, and generating an output data signal.
2. The driver circuit of claim 1 , wherein the first inverter comprises:
a first transistor having a source connected to the first supply voltage and a gate for receiving the input data signal; and
a second transistor having a source connected to the ground, a gate connected to the gate of the first transistor, and a drain connected to a drain of the first transistor for outputting the inverted version of the input data signal.
3. The driver circuit of claim 2 , wherein the bias-control circuit comprises:
a first resistor that receives the bias signal and is connected to a first node of the driver circuit; and
a capacitor that is connected between the drain of the second transistor and the first node.
4. The driver circuit of claim 3 , wherein the bias-control circuit further comprises:
a third transistor having a source for receiving the bias signal, a gate for receiving an inverted version of an enable signal, and a drain connected to the first resistor; and
a fourth transistor having a source connected to the second supply voltage, a gate for receiving the enable signal, and a drain connected to the drain of the third transistor, wherein the third and fourth transistors are p-channel metal-oxide semiconductor (PMOS) transistors.
5. The driver circuit of claim 3 , wherein a resistance of the first resistor and a capacitance of the capacitor are based on a frequency of the input data signal.
6. The driver circuit of claim 3 , wherein the second inverter comprises:
a third transistor having a source connected to the second supply voltage, a gate connected to the first node for receiving the level-shifted data signal, and a drain connected to a second node of the driver circuit; and
a fourth transistor having a source connected to the ground, a gate connected to the drain of the second transistor, and a drain connected to the second node for generating the output data signal at the second node.
7. The driver circuit of claim 6 , wherein the drain of the third transistor and the drain of the fourth transistor are connected to the second node by way of second and third resistors, respectively.
8. The driver circuit of claim 7 , wherein the first and third transistors are PMOS transistors, and the second and fourth transistors are n-channel metal-oxide semiconductor (NMOS) transistors.
9. A driver circuit, comprising:
a first inverter, connected between a first supply voltage and ground, that receives an input data signal and generates an inverted version of the input data signal, the first inverter comprising:
a first transistor having a source connected to the first supply voltage and a gate for receiving the input data signal; and
a second transistor having a source connected to the ground, a gate connected to the gate of the first transistor, and a drain connected to a drain of the first transistor for outputting the inverted version of the input data signal;
a bias-control circuit, connected between a second supply voltage and the first inverter, that receives the inverted version of the input data signal, a bias signal, and an enable signal and generates a level-shifted data signal at a first node of the driver circuit based on the inverted version of the input data signal, the bias signal, the enable signal, and the second supply voltage, wherein the bias-control circuit reduces a difference between voltage levels of the second supply voltage and the inverted version of the input data signal, and wherein the bias-control circuit comprises:
a third transistor having a source for receiving the bias signal and a gate for receiving an inverted version of the enable signal;
a fourth transistor having a source connected to the second supply voltage, a gate for receiving the enable signal, and a drain connected to a drain of the third transistor;
a first resistor that is connected between the drain of the fourth transistor and the first node; and
a capacitor that is connected between the drain of the second transistor and the first node; and
a second inverter, connected between the second supply voltage and the ground, that is connected to the first node and the first inverter for receiving the level-shifted data signal and the inverted version of the input data signal, respectively, and generating an output data signal at a second node of the driver circuit, the second inverter comprising:
a fifth transistor having a source connected to the second supply voltage, a gate connected to the first node for receiving the level-shifted data signal, and a drain connected to the second node; and
a sixth transistor having a source connected to the ground, a gate connected to the drain of the second transistor, and a drain connected to the second node for generating the output data signal at the second node.
10. The driver circuit of claim 9 , wherein a resistance of the first resistor and a capacitance of the capacitor are based on a frequency of the input data signal.
11. The driver circuit of claim 9 , wherein the drain of the fifth transistor and the drain of the sixth transistor are connected to the second node by way of second and third resistors, respectively.
12. The driver circuit of claim 9 , wherein the first and third through fifth transistors are p-channel metal-oxide semiconductor (PMOS) transistors, and the second and sixth transistors are n-channel metal-oxide semiconductor (NMOS) transistors.
13. The driver circuit of claim 9 , wherein a voltage level of the bias signal is equal to a difference between a voltage level of the second supply voltage and half of a voltage level of the first supply voltage.
14. A serializer-deserializer (SerDes), comprising:
a transmitter that outputs an output data signal, the transmitter comprising:
a control circuit, connected to first and second supply voltages and ground, that generates a first input data signal and a bias signal; and
a transmitter-driver circuit, connected to the control circuit, that includes a first driver circuit, receives the bias signal and the first input data signal, and outputs the output data signal, wherein the first driver circuit comprises:
a first inverter, connected between the first supply voltage and the ground, that receives the first input data signal and generates an inverted version of the first input data signal;
a first bias-control circuit, connected between a second supply voltage and the first inverter, that receives the inverted version of the first input data signal and the bias signal and generates a first level-shifted data signal based on the inverted version of the first input data signal, the bias signal, and the second supply voltage, wherein the first bias-control circuit reduces a difference between voltage levels of the second supply voltage and the inverted version of the first input data signal, and a voltage level of the bias signal is equal to a difference between a voltage level of the second supply voltage and half of a voltage level of the first supply voltage; and
a second inverter, connected between the second supply voltage and the ground, that is connected to the first bias-control circuit and the first inverter for receiving the first level-shifted data signal and the inverted version of the first input data signal, respectively, and generating the output data signal.
15. The SerDes of claim 14 , wherein the transmitter-driver circuit further comprises:
a second driver circuit that receives a second input data signal from the control circuit, wherein the second driver circuit is connected in parallel with the first driver circuit, and wherein the second driver circuit comprises:
a third inverter, connected between the first supply voltage and the ground, that receives the second input data signal and generates an inverted version of the second input data signal;
a second bias-control circuit, connected between the second supply voltage and the third inverter, that receives the inverted version of the second input data signal and the bias signal and generates a second level-shifted data signal based on the inverted version of the second input data signal, the bias signal, and the second supply voltage, wherein the second bias-control circuit reduces a difference between voltage levels of the second supply voltage and the inverted version of the second input data signal; and
a fourth inverter, connected between the second supply voltage and the ground, that is connected to the second bias-control circuit and the third inverter for receiving the second level-shifted data signal and the inverted version of the second input data signal, respectively, and generating the output data signal.
16. The SerDes of claim 15 , wherein each of the first and third inverters comprises:
a first transistor having a source connected to the first supply voltage and a gate for receiving at least one of the first and second input data signals; and
a second transistor having a source connected to the ground, a gate connected to the gate of the first transistor, and a drain connected to a drain of the first transistor for outputting the inverted version of the at least one of the first and second input data signals.
17. The SerDes of claim 16 , wherein the each of the first and second bias-control circuits comprises:
a first resistor that receives the bias signal and is connected to a first node of at least one of the first and second driver circuits; and
a capacitor that is connected between the drain of the second transistor and the first node.
18. The SerDes of claim 17 , wherein the control circuit further generates first and second enable signals corresponding to the first and second driver circuits.
19. The SerDes of claim 18 , wherein each of the first and second bias-control circuits further comprises:
a third transistor having a source for receiving the bias signal, a gate for receiving an inverted version of the at least one of the first and second enable signals, and a drain connected to the first resistor; and
a fourth transistor having a source connected to the second supply voltage, a gate for receiving at least one of the first and second enable signals, and a drain connected to the drain of the third transistor, wherein the third and fourth transistors are p-channel metal-oxide semiconductor (PMOS) transistors.
20. The SerDes of claim 18 , wherein the control circuit generates the first enable signal at a first logic state for enabling the first driver circuit and generates the first enable signal at a second logic state and the first input data signal at the first logic state for disabling the first driver circuit, and wherein the control circuit generates the second enable signal at the first logic state for enabling the second driver circuit and generates the second enable signal at the second logic state and the second input data signal at the first logic state for disabling the second driver circuit.
21. The SerDes of claim 17 , wherein a resistance of the first resistor and a capacitance of the capacitor are based on a frequency of the first and second input data signals.
22. The SerDes of claim 17 , wherein each of the second and fourth inverters comprises:
a third transistor having a source connected to the second supply voltage, a gate connected to the first node for receiving the at least one of the first and second level-shifted data signals, and a drain connected to a second node of the at least one of the first and second driver circuits; and
a fourth transistor having a source connected to the ground, a gate connected to the drain of the second transistor, and a drain connected to the second node for generating the output data signal at the second node.
23. The SerDes of claim 22 , wherein the drain of the third transistor and the drain of the fourth transistor are connected to the second node by way of second and third resistors, respectively.
24. The SerDes of claim 22 , wherein the first and third transistors are PMOS transistors, and the second and fourth transistors are n-channel metal-oxide semiconductor (NMOS) transistors.