Fast transient high-side gate driving circuit
Techniques for improving the transient response in a switching converter are provided. An example of a gate driving circuit for driving a high-side switch in a switching converter according to the disclosure includes a first switch operably coupled to a source lead and a gate lead of the high-side switch, a first super source follower circuit operably coupled to the gate lead of the high-side switch, and a mid-voltage power supply operably coupled to the first super source follower circuit.
1. A gate driving circuit for driving a high-side switch in a switching converter, comprising:
a first switch operably coupled to a source lead and a gate lead of the high-side switch;
a first super source follower circuit operably coupled to the gate lead of the high-side switch, wherein the first super source follower circuit includes at least a p-channel semiconductor switch, a n-channel semiconductor switch and a resistor; and
a mid-voltage power supply operably coupled to the first super source follower circuit.
2. The gate driving circuit of claim 1 wherein the high-side switch is a p-channel semiconductor switch.
3. The gate driving circuit of claim 2 wherein the high-side switch is a p-type field-effect transistor (PFET).
4. The gate driving circuit of claim 1 wherein the p-channel semiconductor switch is a p-type field-effect transistor (PFET) and the n-channel semiconductor switch is a n-type field-effect transistor (NFET).
5. The gate driving circuit of claim 4 wherein a source of the PFET is operably coupled to the gate lead of the high-side switch, and a drain lead of the PFET is operably coupled to a gate lead of the NFET and the resistor.
6. The gate driving circuit of claim 5 wherein the mid-voltage power supply is operably coupled to a gate of the PFET.
7. The gate driving circuit of claim 1 wherein the switching converter is configured to output a desired output voltage and a voltage output of the mid-voltage power supply is greater than a difference between the desired output voltage and a gate-to-source voltage rating for the high-side switch.
8. The gate driving circuit of claim 1 further comprising at least a second super source follower circuit operably coupled between the first super source follower circuit and the mid-voltage power supply.
9. The gate driving circuit of claim 8 further comprising at least a third super source follower circuit operably coupled between the second super source follower circuit and the mid-voltage power supply.
10. A method of constructing a switched-mode power converter, comprising:
configuring the switched-mode power converter including at least a high-side switch and a low-side switch based on a desired output voltage;
operably coupling a gate driving circuit to the high-side switch, wherein the gate driving circuit includes a first switch and a first super source follower circuit;
operably coupling a mid-voltage power supply to the first super source follower circuit, wherein a mid-voltage power supply voltage is based on the desired output voltage and a gate-to-source voltage rating of the high-side switch; and
operably coupling a second super source follower circuit between the first super source follower circuit and the mid-voltage power supply.
11. The method of claim 10 wherein the desired output voltage is greater than the gate-to-source voltage rating for the high-side switch.
12. The method of claim 10 wherein the first super source follower circuit includes at least a p-type field-effect transistor (PFET), a n-type field-effect transistor (NFET), and a resistor, and operably coupling the gate driving circuit to the high-side switch includes connecting a source lead of the PFET and a drain lead of the NFET to a gate lead on the high-side switch.
13. The method of claim 12 wherein operably coupling the mid-voltage power supply to the first super source follower circuit includes operably coupling the mid-voltage power supply to a gate lead on the PFET.
14. The method of claim 10 wherein the mid-voltage power supply voltage is greater than a difference between the desired output voltage and the gate-to-source voltage rating of the high-side switch.
15. A gate driving circuit, comprising:
a power stage switch including a gate-source voltage rating and a drain-source voltage rating, wherein the gate-source voltage rating is lower than the drain-source voltage rating;
a first super source follower circuit operably coupled to a gate lead of the power stage switch, wherein the first super source follower circuit includes at least a p-channel semiconductor switch, a n-channel semiconductor switch and a resistor; and
a mid-voltage power supply operably coupled to the first super source follower circuit.
16. The gate driving circuit of claim 15 wherein the power stage switch is an n-channel semiconductor switch.
17. The gate driving circuit of claim 15 wherein the power stage switch is a p-type field-effect transistor (PFET).
18. The gate driving circuit of claim 15 wherein the p-channel semiconductor switch is a p-type field-effect transistor (PFET) and the n-channel semiconductor switch is a n-type field-effect transistor (NFET).
19. The gate driving circuit of claim 18 wherein the mid-voltage power supply is operably coupled to a gate of the PFET.
20. The gate driving circuit of claim 15 further comprising at least a second super source follower circuit operably coupled between the first super source follower circuit and the mid-voltage power supply.
21. The gate driving circuit of claim 20 further comprising at least a third super source follower circuit operably coupled between the second super source follower circuit and the mid-voltage power supply.
22. An apparatus, comprising:
a power converter means including a power stage switch;
a gate driving means operably coupled to the power stage switch, wherein the gate driving means includes a first super source follower circuit; and
a mid-voltage power means operably coupled to the first super source follower circuit, and
a second super source follower circuit operably coupled between the first super source follower circuit and the mid-voltage power means.
23. The apparatus of claim 22 wherein the power stage switch includes a gate-source voltage rating and a drain-source voltage rating, and the gate-source voltage rating is less than the drain-source voltage rating.
24. The apparatus of claim 23 wherein an output voltage from the power converter means is greater than the gate-source voltage rating.
25. The apparatus of claim 24 wherein the mid-voltage power means provides a mid-voltage value that is greater than a difference between the output voltage and the gate-source voltage rating.
26. The apparatus of claim 22 wherein the first super source follower circuit includes at least a p-type field-effect transistor (PFET), a n-type field-effect transistor (NFET), and a resistor.