# US 6,094,038 A · Buck converter with inductive turn ratio optimization > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 6,094,038 A - Document ID: US6094038A - Status: Granted - Kind: A - Application number: 09/340,575 - Filed: 1999-06-28 - Granted: 2000-07-25 - Earliest claimed: 1999-06-28 - Assignees: Semtech Corporation - Inventors: Patrice R. Lethellier - Web page: https://patentgrep.com/patent/US6094038A ## 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 DC--DC power converter circuit for converting relatively high input voltages to relatively low output voltages employs a buck-type circuit topology with a multiple winding inductor. An optional winding is provided to the inductor to clamp a voltage spike appearing on the drain of one of the switching devices. Optionally, two inductor windings may be capacitively coupled for better efficiency. ## Claims ### Claim 1 A DC--DC synchronous converter, comprising: an input voltage node for connecting to an input voltage; an output voltage node for providing an output voltage; a fixed voltage node, such as ground; a first switching device having a first switching input, a first terminal and a second terminal; a second switching device having a second switching input, a first terminal and a second terminal; and an inductor having a series connected first winding and second winding, said first winding having a first number of turns and said second winding having a second number of turns, said inductor including a center tap connected to said first winding and said second winding, an input connected to said first winding and an output connected to said second winding, said first terminal of said first switching device connected to said input voltage node; said inductor input coupled to said second terminal of said first switching device; said second terminal of said second switching device connected to said fixed voltage node; said first terminal of said second switching device connected to said center tap; and said output of said inductor connected to said output voltage node. ### Claim 2 (depends on 1) A converter according to claim 1, wherein: said first switching device is an N-Channel MOSFET. ### Claim 3 (depends on 1) A converter according to claim 1, wherein: said first switching device is a P-Channel device. ### Claim 4 (depends on 3) A converter according to claim 3, wherein: said P-Channel device is a bi-polar transistor. ### Claim 5 A DC--DC synchronous converter, comprising: an input voltage node for connecting to an input voltage; an output voltage node for providing an output voltage; a fixed voltage node, such as ground; a first switching device having a first switching input, a first terminal and a second terminal; a second switching device having a second switching input, a first terminal and a second terminal; and an inductor having a first winding and a second winding, said first winding having a first number of turns and said second winding having a second number of turns, said first winding magnetically coupled to said second winding, each said winding having a first end and a second end, said first end of said first winding connected to said input voltage node; said second end of said first winding connected to said first terminal of said first switching device; said second terminal of said first switching device connected to said first terminal of said second switching device and to said first end of said second winding; said second terminal of said second switching device connected to said fixed voltage node; and said second end of said second winding connected to said output voltage node. ### Claim 6 (depends on 5) A converter according to claim 5, wherein: said first switching device is an N-Channel MOSFET. ### Claim 7 (depends on 5) A converter according to claim 5, wherein: said first switching device is a P-Channel device. ### Claim 8 (depends on 7) A converter according to claim 7, wherein: said P-Channel device is a bi-polar transistor. ### Claim 9 A DC--DC synchronous converter, comprising: an input voltage node for connecting to an input voltage; an output voltage node for providing an output voltage; a fixed voltage node, such as ground; a first switching device having a first switching input, a first terminal and a second terminal; a second switching device having a second switching input, a first terminal and a second terminal; and an inductor having a first winding, a second winding and a third winding, said first winding having a first number of turns, said second winding having a second number of turns and said third winding having a third number of turns, said first, second and third windings magnetically coupled to one another, each said winding having a first end and a second end, said first ends being all of the same polarity and said second ends being all of the opposite polarity to said first ends, said first end of said first winding connected to said input voltage node; said second end of said first winding connected to said first terminal of said first switching device; said second terminal of said first switching device connected to said first terminal of said second switching device and to said first end of said second winding; said second end of said second winding connected to said output voltage node; said second terminal of said second switching device connected to said fixed voltage node; said first end of said third winding connected to said fixed voltage node; said second end of said third winding connected to the anode of a diode; and a cathode of said diode connected to said output voltage node. ### Claim 10 (depends on 9) A converter according to claim 9, wherein: said first switching device is an N-Channel MOSFET. ### Claim 11 (depends on 9) A converter according to claim 9, wherein: said first switching device is a P-Channel device. ### Claim 12 (depends on 11) A converter according to claim 11, wherein: said P-Channel device is a bi-polar transistor. ### Claim 13 A DC--DC synchronous converter, comprising: an input voltage node for connecting to an input voltage; an output voltage node for providing an output voltage; a fixed voltage node, such as ground; a first switching device having a first switching input, a first terminal and a second terminal; a second switching device having a second switching input, a first terminal and a second terminal; and an inductor having a first winding, a second winding and a third winding, said first winding having a first number of turns, said second winding having a second number of turns and said third winding having a third number of turns, each said winding having a first end and a second end, said first ends being all of the same polarity and said second ends being all of the opposite polarity to said first ends; and said first end of said first winding connected to said input voltage node; said second end of said first winding connected to said first terminal of said first switching device and to a first lead of a first capacitor; said second terminal of said first switching device connected to said first terminal of said second switching device and to said first end of said second winding; said second end of said second winding connected to said output voltage node; said second terminal of said second switching device connected to said fixed voltage node; said first end of said third winding connected to said fixed voltage node; said second end of said third winding connected to the anode of a diode and to a second lead of said first capacitor; and a cathode of said diode connected to said output voltage node. ### Claim 14 (depends on 13) A converter according to claim 13, wherein: said first switching device is an N-Channel MOSFET. ### Claim 15 (depends on 13) A converter according to claim 13, wherein: said first switching device is a P-Channel device. ### Claim 16 (depends on 15) A converter according to claim 15, wherein: said P-Channel device is a bi-polar transistor. ### Claim 17 (depends on 13) A converter according to claim 13, further comprising a second capacitor connected between said input voltage node and said output voltage node. ### Claim 18 (depends on 17) A converter according to claim 17, wherein: said first switching device is an N-Channel MOSFET. ### Claim 19 (depends on 17) A converter according to claim 17, wherein: said first switching device is a P-Channel device. ### Claim 20 (depends on 19) A converter according to claim 19, wherein: said P-Channel device is a bi-polar transistor. ### Claim 21 (depends on 17) A converter according to claim 17, further comprising a third capacitor connected between said second end of said second winding and said second end of said third winding. ### Claim 22 (depends on 21) A converter according to claim 21, wherein: said first switching device is an N-Channel MOSFET. ### Claim 23 (depends on 21) A converter according to claim 21, wherein: said first switching device is a P-Channel device. ### Claim 24 (depends on 23) A converter according to claim 23, wherein: said P-Channel device is a bi-polar transistor.