# US 2018/0026523 A1 · Switching power supply device > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2018/0026523 A1 - Document ID: US20180026523A1 - Status: Published application - Kind: A1 - Application number: 15/548,131 - Filed: 2016-01-15 - Published: 2018-01-25 - Earliest claimed: 2015-02-06 - Assignees: Rohm Co., Ltd. - Applicants: Rohm Co., Ltd. - Inventors: Satoru Nate - Web page: https://patentgrep.com/patent/US20180026523A1 ## CPC - H02M 1/36: Means for starting or stopping converters - H02M 3/33523: {with galvanic isolation between input and output of both the power stage and the feedback loop} - H02M 3/33576: {having at least one active switching element at the secondary side of an isolation transformer} - H02P 27/04: using variable-frequency supply voltage, e.g. inverter or converter supply voltage - H05B 45/10: Controlling the intensity of the light - H05B 45/385: using flyback topology - H02M 1/0006: {Arrangements for supplying an adequate voltage to the control circuit of converters} - 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) - H02P: CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS - H05B: ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL ## Abstract A switching power supply device having: a power supply terminal VCC connected to one end of an output capacitor Co2; a high-voltage terminal VH connected to the input side of an input voltage Vdc; and a starting circuit 101 provided between the power supply terminal VCC and the high-voltage terminal VF, the starting circuit 101 passing a first current for charging the output capacitor Co2 via the power supply terminal VCC. The switching power supply device is provided with: a control circuit 10 for turning a switching element M1 on and off; and a current-supplementing circuit 30 to which the input voltage Vdc is inputted, the current-supplementing circuit 30 being connected to the high-voltage terminal VH, the current-supplementing circuit 30 passing a second current to the output capacitor Co2 side on the basis of the first current. A load L2 can be connected to the other end of the output capacitor. ## Claims ### Claim 1 A switching power supply device, comprising: a transformer including: a primary winding to one end of which an input voltage is applied; a secondary winding; and an auxiliary winding provided on a primary-winding side; a switching element provided in a path of the primary winding; an output capacitor having a potential at one end thereof fixed; a rectifying element provided between another end of the output capacitor and one end of the auxiliary winding, with a cathode of the rectifying element on an output-capacitor side; a control circuit controlling the switching element between ON and OFF, the control circuit including: a power terminal connected to the another end of the output capacitor; a HIGH-voltage terminal connected to an input side of the input voltage; and a start-up circuit provided between the power terminal and the HIGH-voltage terminal, the start-up circuit passing a first current for charging the output capacitor via the power terminal; and a current supplementing circuit receiving the input voltage and connected to the HIGH-voltage terminal, the current supplementing circuit passing a second current to the output-capacitor side based on the first current, wherein a load is connectable to the another end of the output capacitor. ### Claim 2 (depends on 1) The switching power supply device of claim 1, wherein when as a result of the output capacitor being charged, a voltage at the power terminal exceeds a first threshold voltage, the start-up circuit shuts off the first current, and in response to the first current being shut off, the current supplementing circuit makes the second current substantially zero. ### Claim 3 (depends on 2) The switching power supply device of claim 2, wherein the current supplementing circuit includes: a resistor element to one end of which the input voltage is applied and to another end of which the HIGH-voltage terminal is connected; and a transistor of which a control end is connected to the another end of the resistor element, the transistor having the input voltage applied to a current-in end thereof, the transistor having a current-out end thereof connected to the another end of the output capacitor. ### Claim 4 (depends on 3) The switching power supply device of claim 3, wherein the transistor is a PNP transistor of which a base is the control end, an emitter is the current-in end, and a collector is the current-out end. ### Claim 5 (depends on 2) The switching power supply device of claim 2, wherein the start-up circuit includes: a charge transistor provided between the HIGH-voltage terminal and the power terminal; a first comparison circuit comparing the voltage at the power terminal with the first threshold voltage; and a switch provided in a path of the charge transistor, the switch being switched according to a result of comparison by the first comparison circuit. ### Claim 6 (depends on 5) The switching power supply device of claim 5, wherein the start-up circuit further includes: a second comparison circuit comparing the voltage at the power terminal with a second threshold voltage lower than the first threshold voltage; and a current source connected in parallel with the switch, the current source limiting a current, and the switch and the current source are switched between ON and OFF according to results of comparison by the first and second comparison circuits. ### Claim 7 (depends on 5) The switching power supply device of claim 5, wherein the charge transistor is an N-channel MOSFET biased so as to be normally ON. ### Claim 8 (depends on 1) An electronic appliance, comprising: the switching power supply device of claim 1; and a load connected to the another end of the output capacitor in the switching power supply device. ### Claim 9 (depends on 8) The electronic appliance of claim 8, wherein the switching power supply device is an AC/DC converter, the electronic appliance is an air conditioner further including: a motor; and a motor driving circuit receiving an alternating-current voltage to drive and control the motor, and the load is a control circuit that controls the motor driving circuit. ### Claim 10 (depends on 8) The electronic appliance of claim 8, wherein the electronic appliance is an LED lighting device further including: an LED load connected on a secondary side of the transformer in the switching power supply device, the control circuit of the switching power supply device has a function of dimming the LED load, and the load is a control circuit that feeds the control circuit with a dimming signal.