# US 8,541,991 B2 · Power converter with controller operable in selected modes of operation > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 8,541,991 B2 - Document ID: US8541991B2 - Status: Granted - Kind: B2 - Application number: 12/939,639 - Filed: 2010-11-04 - Published: 2011-05-05 - Granted: 2013-09-24 - Earliest claimed: 2008-04-16 - Assignees: Enpirion, Inc. - Applicants: Douglas Dean Lopata; Ashraf W. Lotfi - Inventors: Douglas Dean Lopata; Ashraf W. Lotfi - Web page: https://patentgrep.com/patent/US8541991B2 ## CPC - 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 - 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 A power converter and method of controlling the same for selected modes of operation. In one embodiment, the power converter includes a first power switch coupled to a source of electrical power and a second power switch coupled to the first power switch and to an output terminal of the power converter. The power converter also includes a controller configured to control an operation of the first and second power switches during selected modes of operation. ## Claims ### Claim 1 A controller for use with a circuit having first and second switches operable in a mode of operation, configured to: enable conduction of said first switch until an output characteristic of said circuit exceeds an upper output characteristic threshold level and thereafter control a level of current of said first switch; enable conduction of said second switch; and disable conduction of said second switch when said output characteristic crosses a lower output characteristic threshold level. ### Claim 2 (depends on 1) The controller as recited in claim 1 wherein said controller is configured to: alternately enable conduction of said first and second switches with primary and complementary duty cycles, respectively, in response to said output characteristic of said circuit during a switching cycle; enable conduction of said first switch with said primary duty cycle of said switching cycle until said output characteristic of said circuit exceeds said upper output characteristic threshold level and thereafter control said level of current of said first switch; enable conduction of said second switch with said complementary duty cycle of said switching cycle; and disable conduction of said second switch and terminate said switching cycle when said output characteristic crosses said lower output characteristic threshold level. ### Claim 3 (depends on 1) The controller as recited in claim 1 wherein said circuit is operable in another mode of operation when a time exceeds a predetermined time. ### Claim 4 (depends on 3) The controller as recited in claim 3 wherein said predetermined time is about 600 microseconds beginning from a time when said circuit enters said mode of operation. ### Claim 5 (depends on 1) The controller as recited in claim 1 wherein said circuit is operable in another mode of operation when a time exceeds a predetermined time and said controller is configured to alternately enable conduction of said first and second switches with primary and complementary duty cycles, respectively, in response to said output characteristic of said circuit during a switching cycle. ### Claim 6 (depends on 1) The controller as recited in claim 1 wherein said circuit transitions to said mode of operation when a switching cycle counter exceeds a predetermined count. ### Claim 7 (depends on 1) The controller as recited in claim 1 wherein said circuit is operable in another mode of operation and said controller is configured to: enable conduction of said first switch up to an upper current threshold level and thereafter control a level of current of said first switch; enable conduction of said second switch; and disable conduction of said second switch when a current associated with said second switch reaches a lower current threshold level, wherein said circuit transitions from said another mode of operation to said mode of operation when a switching cycle counter exceeds a predetermined count. ### Claim 8 (depends on 7) The controller as recited in claim 7 wherein at least one of said upper current threshold level and said lower current threshold level is fixed. ### Claim 9 (depends on 1) The controller as recited in claim 1 wherein said controller is configured to control said level of current of said first switch in accordance with an error amplifier and a current mirror. ### Claim 10 (depends on 1) The controller as recited in claim 1 wherein said output characteristic is an output voltage of said circuit, said upper output characteristic threshold level is an upper output voltage threshold level and said lower output characteristic threshold level is a lower output voltage threshold level. ### Claim 11 A method for use with a circuit having first and second switches operable in a mode of operation, comprising: enabling conduction of said first switch until an output characteristic of said circuit exceeds an upper output characteristic threshold level and thereafter controlling a level of current of said first switch; enabling conduction of said second switch; and disabling conduction of said second switch when said output characteristic crosses a lower output characteristic threshold level. ### Claim 12 (depends on 11) The method as recited in claim 11, further comprising: alternately enabling conduction of said first and second switches with primary and complementary duty cycles, respectively, in response to said output characteristic of said circuit during a switching cycle; enabling conduction of said first switch with said primary duty cycle of said switching cycle until said output characteristic of said circuit exceeds said upper output characteristic threshold level and thereafter controlling said level of current of said first switch; enabling conduction of said second switch with said complementary duty cycle of said switching cycle; and disabling conduction of said second switch and terminating said switching cycle when said output characteristic crosses said lower output characteristic threshold level. ### Claim 13 (depends on 11) The method as recited in claim 11 wherein said circuit is operable in another mode of operation when a time exceeds a predetermined time. ### Claim 14 (depends on 13) The method as recited in claim 13 wherein said predetermined time is about 600 microseconds beginning from a time when said circuit enters said mode of operation. ### Claim 15 (depends on 11) The method as recited in claim 11 wherein said circuit is operable in another mode of operation when a time exceeds a predetermined time, said method further comprising alternately enabling conduction of said first and second switches with primary and complementary duty cycles, respectively, in response to said output characteristic of said circuit during a switching cycle. ### Claim 16 (depends on 11) The method as recited in claim 11 wherein said circuit transitions to said mode of operation when a switching cycle counter exceeds a predetermined count. ### Claim 17 (depends on 11) The method as recited in claim 11 wherein said circuit is operable in another mode of operation and said method, further comprises: enabling conduction of said first switch up to an upper current threshold level and thereafter controlling a level of current of said first switch; enabling conduction of said second switch; and disabling conduction of said second switch when a current associated with said second switch reaches a lower current threshold level, wherein said circuit transitions from said another mode of operation to said mode of operation when a switching cycle counter exceeds a predetermined count. ### Claim 18 (depends on 17) The method as recited in claim 17 wherein at least one of said upper current threshold level and said lower current threshold level is fixed. ### Claim 19 (depends on 11) The method as recited in claim 11 further comprising controlling said level of current of said first switch in accordance with an error amplifier and a current mirror. ### Claim 20 (depends on 11) The method as recited in claim 11 wherein said output characteristic is an output voltage of said circuit, said upper output characteristic threshold level is an upper output voltage threshold level and said lower output characteristic threshold level is a lower output voltage threshold level.