# US 10,483,752 B2 · Power supply apparatus and image forming apparatus > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,483,752 B2 - Document ID: US10483752B2 - Status: Granted - Kind: B2 - Application number: 16/198,575 - Filed: 2018-11-21 - Published: 2019-05-30 - Granted: 2019-11-19 - Earliest claimed: 2017-11-29 - Assignees: Canon Kabushiki Kaisha - Applicants: Canon Kabushiki Kaisha - Inventors: Shota Suzuki - Web page: https://patentgrep.com/patent/US10483752B2 ## CPC - H02H 7/042: {for current transformers} - G03G 15/80: {Details relating to power supplies, circuits boards, electrical connections} - H02H 1/0007: {concerning the detecting means (in general G01R or other subclasses of G01; reed switches H01H71/2445)} - H02H 5/042: {using temperature dependent resistors} - H02H 7/04: for transformers - H02H 7/1213: {for DC-DC converters} - H02M 3/33507: {with automatic control of the output voltage or current, e.g. flyback converters (H02M3/33561, H02M3/33569 take precedence)} - H02M 1/0006: {Arrangements for supplying an adequate voltage to the control circuit of converters} - H02M 1/0032: {Control circuits allowing low power mode operation, e.g. in standby mode} - H02M 1/327: {against abnormal temperatures} - 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) - G03G: ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY - 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) ## Abstract The power supply apparatus has a configuration in which a temperature detection element and a voltage division resistance element are connected in series as a voltage division unit for an output voltage from a secondary side of a transformer of the power supply apparatus, and stops output of the power supply apparatus based on an output from the voltage division unit. ## Claims ### Claim 1 A power supply apparatus comprising: a transformer having a primary winding and a secondary winding; a switching element connected in series to the primary winding of the transformer; a control unit configured to control an output voltage induced in the secondary winding of the transformer by driving the switching element; a feedback unit configured to feedback a detection result of a voltage induced on the secondary winding to the control unit; and a detection unit configured to detect an overheat state of the transformer and output an overheat signal to the control unit, wherein the detection unit has a voltage division unit configured to divide the output voltage, wherein the voltage division unit includes a temperature detection element to detect a temperature of the transformer, and a resistance element connected in series to the temperature detection element, the voltage division unit disposed in a vicinity of the transformer, wherein the detection unit outputs the overheat detection signal to the control unit in a case where the detection unit detects the overheat state of the transformer based on a voltage obtained by dividing the output voltage by the voltage division unit, and the control unit turns off the switching element in response to the overheat detection signal output from the detection unit, and stops driving of the switching element. ### Claim 2 (depends on 1) The power supply apparatus according to claim 1, wherein the control unit controls the switching element in response to a switch signal that switches the output voltage, and induces one of a first output voltage and a second output voltage lower than the first output voltage in the secondary winding. ### Claim 3 (depends on 2) The power supply apparatus according to claim 2, comprising a feedback unit configured to output information corresponding to a deviation between the output voltage and a target voltage corresponding to the output voltage to the control unit, wherein the feedback unit includes a first circuit unit configured to operate when the output voltage is the first output voltage, and output the information corresponding to the deviation between the first output voltage and the target voltage corresponding to the first output voltage, and a second circuit unit configured to operate when the output voltage is the second output voltage, and output the information corresponding to the deviation between the second output voltage and the target voltage corresponding to the second output voltage, and wherein the control unit controls the switching element to one of a turn-on state and a turn-off state based on the information output from the feedback unit. ### Claim 4 (depends on 3) The power supply apparatus according to claim 3, wherein the switch signal is input from an external apparatus different from the power supply apparatus. ### Claim 5 (depends on 4) The power supply apparatus according to claim 4, wherein the temperature detection element is a thermistor, wherein the detection unit detects the overheat state of the transformer based on a voltage obtained by dividing the first output voltage by the voltage division unit based on a resistance value of the voltage division resistance element, and a resistance value of the thermistor at a time when a temperature of the thermistor is a first temperature in a case where the output voltage is the first output voltage, and wherein the detection unit detects the overheat state of the transformer based on a voltage obtained by dividing the second output voltage by the voltage division unit based on the resistance value of the voltage division resistance element, and the resistance value of the thermistor at a time when the temperature of the thermistor is a second temperature lower than the first temperature in a case where the output voltage is the second output voltage. ### Claim 6 (depends on 3) The power supply apparatus according to claim 3, wherein the temperature detection element is a thermistor, wherein the detection unit has a control unit for detecting that the transformer is in an overheat state, and the control unit detects an overheat state of the transformer based on a voltage obtained by dividing the first output voltage by the voltage division unit in the case where the output voltage is the first output voltage, and wherein the detection unit detects an overheat state of the transformer based on a voltage obtained by dividing the second output voltage by the voltage division unit in the case where the output voltage is the second output voltage. ### Claim 7 (depends on 6) The power supply apparatus according to claim 6, wherein the control unit has a storage unit configured to store data in which a resistance value of the thermistor and a temperature of the thermistor are associated with each other, wherein the control unit obtains a temperature of the thermistor corresponding to the resistance value of the thermistor calculated based on the voltage divided by the voltage division unit, from the data stored in the storage unit, and wherein the control unit outputs the overheat detection signal to the control unit when the output voltage is the first output voltage in a case where the temperature obtained in the control unit, of the thermistor is equal to or more than the first temperature, or when the output voltage is the second output voltage in a case where the temperature obtained in the control unit, of the thermistor is equal to or more than the second temperature. ### Claim 8 (depends on 7) The power supply apparatus according to claim 7, wherein the control unit outputs the switch signal to the feedback unit to switch the output voltage to one of the first voltage and the second voltage. ### Claim 9 (depends on 5) The power supply apparatus according to claim 5, wherein the temperature of the thermistor changes according to the temperature of the transformer, wherein the first temperature is the temperature of the thermistor at a time when the transformer is in an overheat state in the case where the output voltage is the first output voltage, and the second temperature is the temperature of the thermistor at a time when the transformer is in an overheat state in the case where the output voltage is the second output voltage. ### Claim 10 (depends on 8) The power supply apparatus according to claim 8, wherein the temperature of the thermistor changes according to the temperature of the transformer, wherein the first temperature is the temperature of the thermistor at a time when the transformer is in an overheat state in the case where the output voltage is the first output voltage, and the second temperature is the temperature of the thermistor at a time when the transformer is in an overheat state in the case where the output voltage is the second output voltage. ### Claim 11 An image forming apparatus comprising: an image forming unit configured to perform image formation onto a recording material; and a power supply apparatus configured to supply power to the image forming apparatus, wherein the power supply apparatus includes: a transformer having a primary winding and a secondary winding; a switching element connected in series to the primary winding of the transformer; a control unit configured to control an output voltage induced in the secondary winding of the transformer by driving the switching element; a feedback unit configured to feedback a detection result of a voltage induced on the secondary winding to the control unit; and a detection unit configured to detect an overheat state of the transformer and output an overheat signal to the control unit, wherein the detection unit has a voltage division unit configured to divide the output voltage, wherein the voltage division unit includes a temperature detection element to detect a temperature of the transformer, and a resistance element connected in series to the temperature detection element, the voltage division unit disposed in a vicinity of the transformer, wherein the detection unit outputs an overheat detection signal to the control unit in a case where the detection unit detects the overheat state of the transformer based on a voltage obtained by dividing the output voltage by the voltage division unit, and the control unit turns off the switching element in response to the overheat detection signal output from the detection unit, and stops driving of the switching element. ### Claim 12 (depends on 11) The image forming apparatus according to claim 11 comprising: a controller in which power is supplied from the power supply apparatus, the controller configured to control the image forming unit, wherein the controller outputs the switch signal to switch the output voltage to one of the first voltage and the second voltage, and the control unit controls an operation of the switching element to switch the output voltage in response to the switch signal. ### Claim 13 (depends on 11) The image forming apparatus according to claim 11 wherein the control unit is a controller to which power is supplied from the power supply apparatus, the controller configured to control the image forming unit.