Pre-driver circuit
A pre-driver circuit for use in high speed signaling systems is disclosed. In one particular exemplary embodiment, the pre-driver circuit may comprise an input transistor, an active load, a passive load, and a current source. The input transistor has a gate terminal, a current sinking terminal, and a current sourcing terminal. The active load has a control input coupled to the gate terminal of the input transistor, a current sourcing terminal coupled to the current sinking terminal of the input transistor, and a current sinking terminal. The passive load has a first terminal coupled to the current sinking terminal of the active load and a second terminal coupled to the current sourcing terminal of the active load. The current source is coupled to the current sourcing terminal of the input transistor.
1. A pre-driver circuit comprising:
an input transistor having a gate terminal, a current sinking terminal, and a current sourcing terminal;
first active load having a control input coupled to the gate terminal of the input transistor, a current sourcing terminal coupled to the current sinking terminal of the input transistor, and a current sinking terminal;
a second active load having a control input coupled to the current sourcing terminal of the first active load and to the current sinking terminal of the input transistor, a current sinking terminal coupled to the current sinking terminal of the first active load, and a current sourcing terminal;
a passive load having a first terminal coupled to the current sourcing terminal of the first active load and a second terminal coupled to the current sourcing terminal of the second active load; and
a current source coupled to the current sourcing terminal of the input transistor.
2. The pre-driver circuit of claim 1 , wherein the input transistor is one of a MOS transistor and a bipolar transistor.
3. The pre-driver circuit of claim 2 , wherein the input transistor is an NMOS transistor.
4. The pre-driver circuit of claim 1 , wherein the first active load is one of a MOS transistor and a bipolar transistor.
5. The pre-driver circuit of claim 4 , wherein the first active load is a PMOS transistor.
6. The pre-driver circuit of claim 1 , wherein the passive load is a resistor device.
7. The pre-driver circuit of claim 1 , wherein the current source comprises a transistor controlled by a bias signal.
8. The pre-driver circuit of claim 1 , wherein the current sinking terminal of the first active load and the current sinking terminal of the second active load are coupled to a power supply.
9. The pre-driver circuit of claim 1 , wherein the second active load is one of a MOS transistor and a bipolar transistor.
10. The pre-driver circuit of claim 9 , wherein the second active load is a PMOS transistor.
11. The pre-driver circuit of claim 1 , wherein the input transistor is a first input transistor and the passive load is a first passive load, further comprising:
a second input transistor having a gate terminal, a current sinking terminal, and a current sourcing terminal;
a third active load having a control input coupled to the gate terminal of the second input transistor, a current sourcing terminal coupled to the current sinking terminal of the second input transistor, and a current sinking terminal;
a fourth active load having a control input coupled to the current sourcing terminal of the third active load and to the current sinking terminal of the second input transistor, a current sinking terminal coupled to the current sinking terminal of the third active load, and a current sourcing terminal;
a second passive load having a first terminal coupled to the current sourcing terminal of the third active load and a second terminal coupled to the current sourcing terminal of the fourth active load; and
wherein the current sourcing terminal of the second input transistor is coupled to the current sourcing terminal of the first input transistor.
12. The pre-driver circuit of claim 11 , wherein the second input transistor is one of a MOS transistor and a bipolar transistor.
13. The pre-driver circuit of claim 12 , wherein the second input transistor is an NMOS transistor.
14. The pre-driver circuit of claim 11 , wherein the third active load is one of a MOS transistor and a bipolar transistor.
15. The pre-driver circuit of claim 14 , wherein the third active load is a PMOS transistor.
16. The pre-driver circuit of claim 11 , wherein the second passive load is a resistor device.
17. The pre-driver circuit of claim 11 , wherein the current source comprises a transistor controlled by a bias signal.
18. The pre-driver circuit of claim 11 , wherein the current sinking terminal of the third active load and the current sinking terminal of the fourth active load are coupled to a power supply.
19. The pre-driver circuit of claim 11 , wherein the second active load is one of a MOS transistor and a bipolar transistor.
20. The pre-driver circuit of claim 19 , wherein the second active load is a PMOS transistor.
21. The pre-driver circuit of claim 11 , wherein the fourth active load is one of a MOS transistor and a bipolar transistor.
22. The pre-driver circuit of claim 21 , wherein the fourth active load is a PMOS transistor.