# US 2014/0192441 A1 · DC/DC Converter with III-Nitride Switches > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2014/0192441 A1 - Document ID: US20140192441A1 - Status: Published application - Kind: A1 - Application number: 14/210,151 - Filed: 2014-03-13 - Published: 2014-07-10 - Earliest claimed: 2007-11-27 - Assignees: International Rectifier Corporation - Applicants: International Rectifier Corporation - Inventors: Michael A. Briere; Jason Zhang; Bo Yang - Web page: https://patentgrep.com/patent/US20140192441A1 ## CPC - H02H 7/1213: {for DC-DC converters} - H02M 1/32: Means for protecting converters other than automatic disconnection - H02M 3/1588: {comprising at least one synchronous rectifier element (H02M3/1582, H02M3/1584 take precedence)} - Y02B 70/10: Technologies improving the efficiency by using switched-mode power supplies [SMPS], i.e. efficient power electronics conversion e.g. power factor correction or reduction of losses in power supplies or efficient standby modes - H02H: EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS (indicating or signalling undesired working conditions G01R, e.g. G01R31/00, G08B; locating faults along lines G01R31/08; emergency protective devices H01H) - H02M: APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF (transformers H01F; dynamo-electric converters H02K47/00; controlling transformers, reactors or choke coils, control or regulation of electric motors, generators or dynamo-electric converters H02P) - Y02B: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS ## Abstract 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. ## Claims ### Claim at position 1 1-18. (canceled) ### Claim 19 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. ### Claim 20 (depends on 19) The buck converter of claim 19, wherein at least one of said control switch and said synchronous switch comprises a depletion-mode GaN HEMT. ### Claim 21 (depends on 19) The buck converter of claim 19, wherein said protection circuitry is configured to disable current conduction through said control switch while said control circuitry is not powered up. ### Claim 22 (depends on 19) The buck converter of claim 19, wherein said protection circuitry is coupled between said input of said buck converter and said control switch. ### Claim 23 (depends on 22) The buck converter of claim 22, wherein said protection circuitry disables current conduction through said control switch by disconnecting said input of said buck converter from said control switch. ### Claim 24 (depends on 19) The buck converter of claim 19, wherein said protection circuitry comprises an enhancement-mode transistor. ### Claim 25 (depends on 19) The buck converter of claim 19, wherein said protection circuitry comprises a silicon p-channel transistor. ### Claim 26 (depends on 19) The buck converter of claim 19, wherein said protection circuitry comprises a silicon n-channel transistor. ### Claim 27 (depends on 19) The buck converter of claim 19, further comprising another protection switch configured to disable current conduction through said synchronous switch while said control circuitry is not powered up. ### Claim 28 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. ### Claim 29 (depends on 28) The buck converter of claim 28, wherein said enhancement-mode transistor comprises a silicon p-channel transistor. ### Claim 30 (depends on 28) The buck converter of claim 28, wherein said enhancement-mode transistor comprises a silicon n-channel transistor. ### Claim 31 (depends on 28) The buck converter of claim 28, wherein said enhancement-mode transistor is coupled between said input of said buck converter and said control switch. ### Claim 32 (depends on 28) The buck converter of claim 28, wherein at least one of said control switch and said synchronous switch comprises a depletion-mode GaN transistor. ### Claim 33 (depends on 28) The buck converter of claim 28, further comprising another enhancement-mode transistor configured to disable said synchronous switch while said control circuitry is not powered up.