High voltage converter power stage
Described embodiments include a power driver circuit having a first transistor coupled between an input voltage terminal and an intermediate terminal, and having a first control terminal. A second transistor is coupled between the intermediate terminal and a switching terminal, and has a second control terminal coupled to an output of a gate drive circuit. A first diode has a first anode coupled to the input voltage terminal, and a first cathode coupled to the first control terminal through a resistor. A first voltage clamp circuit is coupled between the first control terminal and the intermediate terminal. A second voltage clamp circuit is coupled between the first control terminal and the switching terminal. A second diode is coupled between the first control terminal and a voltage supply terminal.
1. A circuit comprising:
a first transistor having first and second terminals and a control terminal, the first terminal coupled to an input voltage terminal;
a second transistor having a first terminal coupled to the second terminal of the first transistor and having a second terminal coupled to switching terminal;
a first diode having a first anode and a first cathode, wherein the first anode is coupled to the input voltage terminal;
a resistor having a first terminal coupled to the first cathode and having a second terminal coupled to the control terminal;
a first voltage clamp circuit having a first terminal coupled to the control terminal and having a second terminal coupled to the second terminal of the first transistor and to the first terminal of the second transistor;
a second voltage clamp circuit having a first terminal coupled to the control terminal and having a second terminal coupled to a voltage supply terminal; and
a second diode having a second cathode coupled to the control terminal and having a second anode coupled to the voltage supply terminal.
2. The circuit of claim 1 , further comprising a capacitor coupled between the voltage supply terminal and the switching terminal.
3. The circuit of claim 1 , wherein the first voltage clamp has a clamping voltage equal to a voltage at the voltage supply terminal.
4. The circuit of claim 3 , wherein the second voltage clamp has a clamping voltage equal to the first maximum voltage rating.
5. The circuit of claim 1 , further comprising a third voltage clamp circuit coupled in parallel with the resistor.
6. The circuit of claim 5 , wherein the third voltage clamp has a clamping voltage equal to the clamping voltage of the second voltage clamp circuit.
7. The circuit of claim 1 , further comprising a gate drive circuit having an output coupled to a control terminal of the second transistor and having a supply input terminal coupled to the voltage supply terminal.
8. The circuit of claim 1 , further comprising an inductor coupled between the switching terminal and an output voltage terminal.
9. The circuit of claim 1 , wherein the circuit is included in a voltage regulator circuit.
10. The circuit of claim 9 , wherein the voltage regulator circuit is a buck voltage regulator circuit.
11. The circuit of claim 1 , wherein a first maximum voltage rating of the first transistor is equal to a second maximum voltage rating of the second transistor.
12. The circuit of claim 3 , wherein the first and second transistors are each a n-channel field effect transistor (NFET).
13. A voltage regulator circuit comprising:
a gate drive circuit having a supply input terminal and a gate drive output, wherein the supply input terminal is coupled to a voltage supply terminal;
a first transistor coupled between an input voltage terminal and an intermediate terminal, and having a first control terminal;
a second transistor coupled between the intermediate terminal and a switching terminal and having a second control terminal, wherein the second control terminal is coupled to the gate drive output;
a first diode having a first anode and a first cathode, wherein the first anode is coupled to the input voltage terminal;
a resistor coupled between the first cathode and the first control terminal;
a first voltage clamp circuit coupled between the first control terminal and the intermediate terminal;
a second voltage clamp circuit coupled between the first control terminal and the switching terminal; and
a second diode coupled between the first control terminal and the voltage supply terminal.
14. The voltage regulator circuit of claim 13 , wherein the first voltage clamp has a clamping voltage equal to a voltage at the voltage supply terminal.
15. The voltage regulator circuit of claim 14 , wherein the second voltage clamp has a clamping voltage equal to the first maximum voltage rating.
16. The voltage regulator circuit of claim 13 , further comprising:
an inductor coupled between the switching terminal and an output voltage terminal;
a diode coupled between the switching terminal and a ground terminal; and
a capacitor coupled between the output voltage terminal and the ground terminal.
17. The voltage regulator circuit of claim 13 , further comprising a third voltage clamp circuit coupled in parallel with the resistor.
18. The voltage regulator circuit of claim 17 , wherein the third voltage clamp has a clamping voltage equal to the clamping voltage of the second voltage clamp circuit.
19. The voltage regulator circuit of claim 18 , wherein a first maximum voltage rating of the first transistor is equal to a second maximum voltage rating of the second transistor.
20. The voltage regulator circuit of claim 15 , wherein the first and second transistors are each a n-channel field effect transistor (NFET).
21. The circuit of claim 1 , wherein the control terminal of the first transistor is a first control terminal, and the second transistor has a second control terminal that is capable of being driven separately from the first control terminal.