DC/DC converter with III-nitride switches
Disclosed is a buck converter for converting a high voltage at the input of the buck converter to a low voltage at the output of the buck converter. The buck converter includes a control circuitry configured to control a duty cycle of a control switch, the control switch being interposed between the input and the output of the buck converter. A synchronous switch is interposed between the output and ground. The control switch and the synchronous switch comprise depletion-mode III-nitride transistors. In one embodiment, at least one of the control switch and the synchronous switches comprises a depletion-mode GaN HEMT. The buck converter further includes protection circuitry configured to disable current conduction through the control switch while the control circuitry is not powered up.
1. A buck converter comprising:
a control circuitry coupled to a control switch;
said control switch comprising a III-nitride transistor and interposed between an input and an output of said buck converter;
a synchronous switch comprising another III-nitride transistor and interposed between said output and a ground;
a protection circuitry configured to disable said control switch.
2. The buck converter of claim 1 , wherein at least one of said control switch and said synchronous switch comprises a depletion-mode GaN HEMT.
3. The buck converter of claim 1 , wherein said protection circuitry is configured to disable current conduction through said control switch while said control circuitry is not powered up.
4. The buck converter of claim 1 , wherein said protection circuitry is coupled between said input of said buck converter and said control switch.
5. The buck converter of claim 4 , wherein said protection circuitry disables current conduction through said control switch by disconnecting said input of said buck converter from said control switch.
6. The buck converter of claim 1 , wherein said protection circuitry comprises an enhancement-mode transistor.
7. The buck converter of claim 1 , wherein said protection circuitry comprises a silicon p-channel transistor.
8. The buck converter of claim 1 , wherein said protection circuitry comprises a silicon n-channel transistor.
9. The buck converter of claim 1 , further comprising another protection switch configured to disable current conduction through said synchronous switch while said control circuitry is not powered up.
10. A buck converter comprising:
a GaN control switch interposed between an input and an output of said buck converter, and a GaN synchronous switch interposed between said output and said ground;
a control circuitry coupled to said control switch;
an enhancement-mode transistor coupled between said input and said control switch to disable said control switch while said control circuitry is not powered up.
11. The buck converter of claim 10 , wherein said enhancement-mode transistor comprises a silicon p-channel transistor.
12. The buck converter of claim 10 , wherein said enhancement-mode transistor comprises a silicon n-channel transistor.
13. The buck converter of claim 10 , wherein said enhancement-mode transistor is coupled between said input of said buck converter and said control switch.
14. The buck converter of claim 10 , wherein at least one of said control switch and said synchronous switch comprises a depletion-mode GaN transistor.
15. The buck converter of claim 10 , further comprising another enhancement-mode transistor configured to disable said synchronous switch while said control circuitry is not powered up.