# US 2018/0323640 A1 · System and Method to Increase a Hold Up Time of a Power Supply Unit > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2018/0323640 A1 - Document ID: US20180323640A1 - Status: Published application - Kind: A1 - Application number: 15/585,979 - Filed: 2017-05-03 - Published: 2018-11-08 - Earliest claimed: 2017-05-03 - Assignees: Dell Products L.P. - Applicants: Dell Products, LP - Inventors: Tsai-Fu Hung; Rita Joy F. Miranda; Shih-Chieh Wang - Web page: https://patentgrep.com/patent/US20180323640A1 ## CPC - H02J 9/061: {for DC powered loads} - H02M 1/10: Arrangements incorporating converting means for enabling loads to be operated at will from different kinds of power supplies, e.g. from AC or DC - H02J 7/865: {Battery or charger load switching, e.g. concurrent charging and load supply (H02J7/50 takes precedence)} - H02M 3/33584: {Bidirectional converters} - Y02B 70/30: Systems integrating technologies related to power network operation and communication or information technologies for improving the carbon footprint of the management of residential or tertiary loads, i.e. smart grids as climate change mitigation technology in the buildings sector, including also the last stages of power distribution and the control, monitoring or operating management systems at local level - Y04S 20/20: End-user application control systems - H02J: ELECTRIC POWER NETWORKS; CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY - 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 - Y04S: SYSTEMS INTEGRATING TECHNOLOGIES RELATED TO POWER NETWORK OPERATION, COMMUNICATION OR INFORMATION TECHNOLOGIES FOR IMPROVING THE ELECTRICAL POWER GENERATION, TRANSMISSION, DISTRIBUTION, MANAGEMENT OR USAGE, i.e. SMART GRIDS ## Abstract A multiple power supply system includes first and second power supply units. The first power supply unit provides a main output voltage while in a normal mode of operation. The first power supply unit includes a first bulk capacitor, and first standby power circuitry. The first standby power circuitry provides a standby voltage while the first power supply unit is in the normal mode of operation. The second power supply unit provides the main output voltage while in the normal mode of operation. The first power supply unit includes a second bulk capacitor, and second standby power circuitry. The second standby power circuitry provides the standby voltage while the first power supply unit is in the normal mode of operation, and enables reverse charging of the second bulk capacitor by the first power supply unit while the second power supply unit is in a reverse charging mode of operation. ## Claims ### Claim 1 A multiple power supply system comprising: a first power supply unit to provide a main output voltage while in a normal mode of operation, the first power supply unit including: a first bulk capacitor; and first standby power circuitry, the first standby power circuitry to provide a standby voltage while the first power supply unit is in the normal mode of operation; and a second power supply unit to provide the main output voltage while in the normal mode of operation, the second power supply unit including: a second bulk capacitor; and second standby power circuitry, the second standby power circuitry to provide the standby voltage while the first power supply unit is in the normal mode of operation, and to enable reverse charging of the second bulk capacitor by the first power supply unit while the second power supply unit is in a reverse charging mode of operation. ### Claim 2 (depends on 1) The multiple power supply system of claim 1 wherein the second power supply unit enters the reverse charging mode of operation in response to an input voltage source to the second power supply unit being off. ### Claim 3 (depends on 2) The multiple power supply system of claim 2 wherein the second power supply unit provides a lower charging cycle in the reverse charging mode of operation in response to the second bulk capacitor being charged to a predetermined voltage level. ### Claim 4 (depends on 3) The multiple power supply system of claim 3 wherein the second power supply unit is maintained in a hot spare mode after the second power supply unit ends the reverse charging mode of operation. ### Claim 5 (depends on 1) The multiple power supply system of claim 1 wherein the first and second bulk capacitors combine to provide both the main output voltage and the standby voltage for a hold up amount of time in response to both a first input voltage to the first power supply unit and a second input voltage to the second power supply unit being off. ### Claim 6 (depends on 1) The multiple power supply system of claim 1 wherein the second standby circuitry comprises a standby integrated circuit, the second standby circuitry is maintained in the reverse charging mode in response to a working voltage of the standby integrated circuit being pulled to ground. ### Claim 7 (depends on 6) The multiple power supply system of claim 6 wherein the working voltage of the standby integrated circuit is pulled to ground by a digital signal processor of the second standby circuitry. ### Claim 8 A multiple power supply system comprising: a first power supply unit to provide a main output voltage while in a normal mode of operation; and a second power supply unit to provide the main output voltage while in the normal mode of operation, the second power supply unit including: a bulk capacitor; and standby power circuitry, the standby power circuitry including a digital signal processor, the digital signal processor to control a charging of the bulk capacitor while the second power supply unit is in a reverse charging mode. ### Claim 9 (depends on 8) The multiple power supply system of claim 8 wherein the second power supply unit enters the reverse charging mode of operation in response to an input voltage source to the second power supply unit being off. ### Claim 10 (depends on 9) The multiple power supply system of claim 9 wherein the second power supply unit provides a lower charging cycle in the reverse charging mode of operation in response to the second bulk capacitor being charged to a predetermined voltage level. ### Claim 11 (depends on 10) The multiple power supply system of claim 10 wherein the second power supply unit is maintained in a hot spare mode after the second power supply unit ends the reverse charging mode of operation. ### Claim 12 (depends on 8) The multiple power supply system of claim 8 wherein the bulk capacitor to provide the main output voltage for a hold up amount of time in response to both a first input voltage to the first power supply unit and a second input voltage to the second power supply unit being off. ### Claim 13 (depends on 8) The multiple power supply system of claim 8 wherein the second standby circuitry comprises a standby integrated circuit, the second standby circuitry is maintained in the reverse charging mode in response to a working voltage of the standby integrated circuit being pulled to ground. ### Claim 14 A method comprising: detecting a loss of a first input voltage source to a first power supply unit of a multiple power supply system, the multiple power supply system including the first power supply unit and a second power supply unit; operating the first power supply unit in a reverse charging mode of operation in response to the loss of the first input voltage source; charging a bulk capacitor of the first power supply unit while in the reverse charging mode of operation; determining whether a voltage level of the bulk capacitor is equal to a threshold voltage level; providing a lower charging cycle in the reverse charging mode of operation in response to the second bulk capacitor being charged to a predetermined voltage level; detecting a loss of a second input voltage source to the second power supply unit; operating in a hold up mode of operation in response to the loss of the first input voltage source; and providing an output voltage from the bulk capacitor while in the hold up mode of operation. ### Claim 15 (depends on 14) The method of claim 14 further comprising: determining whether a standby power integrated circuit of the second power supply unit is off while the first power supply unit is in the reverse charging mode of operation; and forcing the standby power integrated circuit to power off in response to determining that the standby power integrated circuit is not off. ### Claim 16 (depends on 15) The method of claim 15 wherein forcing the standby integrated circuit to power off protects components of the power supply unit while in the reverse charging mode of operation. ### Claim 17 (depends on 14) The method of claim 14 wherein forcing the standby integrated circuit to power off comprises: turning on a transistor coupled to the standby integrated circuit to pull a working voltage of the standby integrated circuit to ground. ### Claim 18 (depends on 14) The method of claim 14 further comprising: determining whether a high current is received in the first power supply unit; and ending the reverse charging mode for a predetermined amount of time is response to determining that the high current is received in the first power supply unit. ### Claim 19 (depends on 14) The method of claim 14 further comprising: operating the first power supply unit is a hot space mode of operation in response to the reverse charging mode of operation ending and prior to resuming the normal mode of operation. ### Claim 20 (depends on 19) The method of claim 19 further comprising: maintaining the voltage level of the bulk capacitor at the predetermined voltage level while operating in the hot spare mode of operation.