# US 7,613,020 B2 · Discharge lamp ballast apparatus comprising DC/DC converters having at least two transformers and outputting two kinds of voltages > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 7,613,020 B2 - Document ID: US7613020B2 - Status: Granted - Kind: B2 - Application number: 11/666,069 - Filed: 2005-10-25 - Published: 2007-10-25 - Granted: 2009-11-03 - Earliest claimed: 2005-01-13 - Assignees: Mitsubishi Electric Corporation - Inventors: Yasuhiro Nukisato; Takashi Ohsawa - Web page: https://patentgrep.com/patent/US7613020B2 ## CPC - H05B 41/2886: {comprising a controllable preconditioner, e.g. a booster} - H05B 41/388: {for a transition from glow to arc} - Y02B 20/00: Energy efficient lighting technologies, e.g. halogen lamps or gas discharge lamps - H05B: ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL - Y02B: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS ## Abstract A discharge lamp ballast apparatus includes a DC/DC converter having a transformer T1 and a DC/DC converter having a transformer T2, which are connected in parallel; a control section 4 for controlling the output voltages of the DC/DC converters by varying their duties with shifting the operation phases of the transformers T1 and T2 of the DC/DC converters; and a voltage-multiplier rectifier circuit having diodes 7-9 and capacitors 10-12 for generating a high voltage used for starting a discharge lamp 22 by utilizing the potential difference between the output voltages of the transformers T1 and T2. ## Claims ### Claim 1 A discharge lamp ballast apparatus comprising: a plurality of DC/DC converters which include transformers for boosting a power supply voltage, and are connected in parallel; control unit for controlling operation of the transformers of said DC/DC converters; and a voltage-multiplier rectifier circuit that generates a high voltage to start a discharge lamp by utilizing a potential difference between output voltages of the transformers, wherein said control unit controls the transformers in a manner as to shift operation phases of the transformers of said DC/DC converters; and further wherein said voltage-multiplier rectifier circuit includes a Cockcroft-Walton circuit. ### Claim 2 (depends on 1) The discharge lamp ballast apparatus according to claim 1, wherein said voltage-multiplier rectifier circuit receives the voltages from secondary windings of the transformers which generate a ballast voltage of the discharge lamp. ### Claim 3 (depends on 1) The discharge lamp ballast apparatus of claim 1, further comprising a discharge lamp ignition circuit that receives the output of the voltage-multiplier rectifier circuit. ### Claim 4 (depends on 1) The discharge lamp apparatus of claim 1, further comprising a DC/AC inverter. ### Claim 5 (depends on 4) The discharge lamp ballast apparatus of claim 4, wherein said DC/AC includes at least one transistor. ### Claim 6 (depends on 5) The discharge lamp apparatus of claim 5, wherein said at least one transistor comprises an n-channel FET. ### Claim 7 (depends on 5) The discharge lamp ballast of claim 5, further comprising a first electrode of a discharge lamp connected to said at least one transistor. ### Claim 8 A discharge lamp ballast apparatus comprising: a plurality of DC/DC converters which include transformers for boosting a power supply voltage, and are connected in parallel; control unit for controlling operation of the transformers of said DC/DC converters; and a voltage-multiplier rectifier circuit that generates a high voltage to start a discharge lamp by utilizing a potential difference between output voltages of the transformers, wherein said control unit controls the transformers in a manner as to shift operation phases of the transformers of said DC/DC converters; and further wherein said control unit adjusts the operation phases and duty of the transformers of said DC/DC converters in a manner as to increase the potential difference to be supplied to said voltage-multiplier rectifier circuit. ### Claim 9 A discharge lamp ballast apparatus comprising: a plurality of DC/DC converters which include transformers for boosting a power supply voltage, and are connected in parallel: control unit for controlling operation of the transformers of said DC/DC converters; and a voltage-multiplier rectifier circuit that generates a high voltage to start a discharge lamp by utilizing a potential difference between output voltages of the transformers, wherein said control unit controls the transformers in a manner as to shift operation phases of the transformers of said DC/DC converters; and further wherein said control unit halts voltage outputs of the transformers when a voltage across a capacitor for holding an output voltage of said DC/DC converters at a ballast voltage of the discharge lamp reaches the ballast voltage; and causes the transformers to output voltages when the voltage across the capacitor becomes less than the ballast voltage. ### Claim 10 A discharge lamp ballast apparatus comprising: a plurality of DC/DC converters, where said converters include transformers that boost a power supply voltage and said transformers are connected in parallel; a control unit that controls operation of said DC/DC converters; and a high voltage generating circuit, said generating circuit including at least a first capacitor and a first diode and a second capacitor and a second diode, and where said generating circuit charges said first capacitor to a first voltage with a DC voltage, said DC voltage including an output voltage of one transformer, said output voltage of one transformer being rectified by said first diode at a first timing of AC waveforms output from said one transformer, said generating circuit charges said second capacitor to a second voltage, said second voltage being the sum of the first voltage and the DC voltage, where the DC voltage further includes an output voltage of a second transformer, said output voltage of a second transformer being rectified by said second diode at a second timing, said second timing having a different phase than said first timing, thereby making the DC voltage higher than the output voltages of said transformers at terminals of said second capacitor, and said control unit controls said DC/DC converters in such manner as to shift operation phases of said transformers. ### Claim 11 (depends on 10) The discharge lamp ballast apparatus of claim 10, where the second voltage is higher than the first voltage at the second timing. ### Claim 12 (depends on 10) The discharge lamp ballast apparatus of claim 10, where said first and second capacitors are connected between outputs of said transformers, and where said generating circuit charges said first capacitor via said first diode at the first timing; and charges said second capacitor via said first capacitor and said second diode at the second timing, where an output polarity of at least one transformer is inverted. ### Claim 13 (depends on 10) The discharge lamp ballast apparatus of claim 10, said high voltage generating circuit further including a third capacitor and a third diode, and where said generating circuit: charges said third capacitor to the voltage stored in said second capacitor at a third timing, said third timing being a repetition of the first timing and having the same phase as the first timing; and generates a voltage higher than an output voltage of said second capacitor at terminals of said third capacitor. ### Claim 14 (depends on 10) The discharge lamp ballast apparatus of claim 10, said high voltage generating circuit further including a certain amount, n, of capacitors and said certain amount, n, of diodes, and where said generating circuit: charges the first capacitor to an odd timing voltage corresponding to a potential difference of the output voltages of said transformers at a first timing and an odd-numbered timing having the same phase as the first timing; charges an odd-numbered capacitor after a third capacitor to a voltage corresponding to a voltage stored in an even-numbered capacitor immediately before said odd numbered capacitor; charges the second capacitor to an even timing voltage that is the sum of the odd timing voltage and voltage corresponding to a potential difference of the output voltages of said transformers at a second timing and an even-numbered timing having the same phase as the second timing; and charges an even-numbered capacitor after the fourth capacitor to a voltage corresponding to a voltage stored in an odd-numbered capacitor immediately before said even-numbered capacitor; said circuit thereby generating substantially n times the output voltages of said transformers at terminals of an nth capacitor.