Opinion ID: 4199980
Heading Depth: 2
Heading Rank: 1

Heading: DC-DC Power Converters

Text: The SynQor Patents claim systems and methods for DC-DC power conversion. See generally ’290 patent col. 17 l. 9–col. 18 l. 35; ’021 patent col. 6 l. 21–col. 8 l. 60. Direct current (DC) flows in only one direction, whereas alternating current (AC) periodically reverses direction. AC power supplied from a utility is converted to DC by a “front end converter.” A DC-DC converter receives the DC output of a front end converter and transforms it into one or more lower DC voltages. The DC-DC converters at issue in this appeal are designed to drive logic circuitry in large computer and telecommunications systems that typically require a number of different power voltages. The claimed converters perform two general operations in sequence: “isolation” and “regulation.” Isolation converts a DC input into 1 Related appeal no. 2016-2282, which involves the reexamination of another SynQor patent (U.S. Patent No. 7,564,702), presents unique issues addressed in a separate opinion issued today. 4 VICOR CORP. v. SYNQOR, INC. AC, reduces the AC voltage using a transformer, and converts AC back to DC at a voltage level lower than the DC input. Regulation then restricts that isolated output down to a DC voltage appropriate for driving logic circuity.
Isolation enhances safety and prevents unwanted noise by using a transformer to lower voltage without using wires connecting inputs and outputs. A transformer comprises “primary” and “secondary” windings, such as coiled wires. The transformer’s input is connected to the primary winding, which transfers electrical energy to the secondary winding via magnetic fields. The transformer’s output from the secondary winding is a fraction, or multiple, of the transformer’s input determined by the ratio of turns in the respective primary and secondary windings. For example, a transformer with a primary winding that has twice as many turns as the secondary winding will have an output voltage that is half of its input. Isolation circuitry converts the secondary winding’s AC output to DC using rectifiers. The SynQor Patents’ claims all require use of “controlled” rectifiers, which use control signals and circuitry to reverse or prevent the flow of current in one direction. Embodiments of the SynQor Patents’ inventions use a particular type of pre-existing controlled rectifier known as a “synchronous” rectifier, which uses a waveform of current flow across one of the transformer’s windings to control switching circuitry that generates a DC output.
Regulation circuitry receives an isolated DC output and regulates it down to appropriate voltage(s) to drive logic circuitry. Regulation was known to be implemented using at least two types of regulators: “switching” regulators and “linear” regulators. Switching regulators include VICOR CORP. v. SYNQOR, INC. 5 a transistor-implemented switch, which turns on and off in response to one or more parameters sensed in the circuit to maintain output voltage at a predefined value. Linear regulators regulate an output by varying the resistance of the regulator.
Prior art power architectures for large computer and telecommunications systems used DC-DC power converters that integrated isolation and regulation circuitry in each individual converter. The presence of isolation circuitry in every converter took up valuable space on circuit boards where the converters were located, which could have been used for additional microprocessors, memory, or logic circuitry.