# US 8,541,996 B2 · Power control device, power supply device, and power control method > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 8,541,996 B2 - Document ID: US8541996B2 - Status: Granted - Kind: B2 - Application number: 12/778,812 - Filed: 2010-05-12 - Published: 2010-11-18 - Granted: 2013-09-24 - Earliest claimed: 2009-05-18 - Assignees: Fujitsu Semiconductor Limited - Applicants: Toshihiko Kasai; Hidenobu Ito - Inventors: Toshihiko Kasai; Hidenobu Ito - Web page: https://patentgrep.com/patent/US8541996B2 ## CPC - H02M 3/1588: {comprising at least one synchronous rectifier element (H02M3/1582, H02M3/1584 take precedence)} - H02M 1/0025: {Arrangements for modifying reference values, feedback values or error values in the control loop of a converter} - H02M 1/0032: {Control circuits allowing low power mode operation, e.g. in standby mode} - Y02B 70/10: Technologies improving the efficiency by using switched-mode power supplies [SMPS], i.e. efficient power electronics conversion e.g. power factor correction or reduction of losses in power supplies or efficient standby modes - 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 ## Abstract A power control device for performing switching control for an output voltage of a power supply device includes a signal generation circuit for comparing a difference between a value of the output voltage and a value of a first reference voltage with a value of a second reference voltage, and for stopping the switching control when a value of the difference is less than or equal to the value of the second reference voltage, and an adjuster circuit for adjusting the second reference voltage based on a ratio between a value of an input voltage and the value of the output voltage. ## Claims ### Claim 1 A power control device for performing switching control for an output voltage of a power supply device, the power control device comprising: a signal generation circuit configured to receive a second reference voltage and a difference between a value of the output voltage and a value of a first reference voltage, compare the difference with the second reference voltage, and stop the switching control when a value of the difference is less than or equal to the value of the second reference voltage; and an adjuster circuit configured to receive an input voltage and the output voltage, adjust the second reference voltage based on a ratio between a value of an input voltage and the value of the output voltage and output an adjusted second reference voltage to the signal generation circuit as the second reference voltage. ### Claim 2 (depends on 1) The power control device according to claim 1, wherein the adjuster circuit increases the value of the second reference voltage as the ratio of the value of the output voltage to the value of the input voltage approaches 1:1. ### Claim 3 (depends on 2) The power control device according to claim 2, wherein the adjuster circuit increases the value of the second reference voltage when the value of the input voltage becomes less than or equal to a twofold value of the output voltage. ### Claim 4 (depends on 2) The power control device according to claim 2, wherein the adjuster circuit comprises: a first input circuit configured to generate a current proportional to the input voltage; a second input circuit configured to generate a current proportional to the output voltage; and a computing circuit configured to compute the ratio of the value of the output voltage to the value of the input voltage. ### Claim 5 (depends on 1) The power control device according to claim 1, wherein the switching control is a step-down peak current control including slope compensation. ### Claim 6 A power supply device, comprising: a switch configured to supply power from an input end of the power supply device to an output end of the power supply device based on switching control; a signal generation circuit configured to receive a second reference voltage and a difference between a value of an output voltage and a value of a first reference voltage, compare the difference with the second reference voltage, and stop the switching control for the switch when a value of the difference is less than or equal to the value of the second reference voltage; and an adjuster circuit configured to receive an input voltage and the output voltage, adjust the second reference voltage based on a ratio between a value of an input voltage and the value of the output voltage and output an adjusted second reference voltage to the signal generation circuit as the second reference voltage. ### Claim 7 (depends on 6) The power supply device according to claim 6, wherein the adjuster circuit increases the value of the second reference voltage as the ratio of the value of the output voltage to the value of the input voltage approaches 1:1. ### Claim 8 (depends on 7) The power supply device according to claim 7, wherein the adjuster circuit increases the value of the second reference voltage when the value of the input voltage becomes less than or equal to a twofold value of the output voltage. ### Claim 9 (depends on 7) The power supply device according to claim 7, wherein the adjuster circuit comprises: a first input circuit configured to generate a current proportional to the input voltage; a second input circuit configured to generate a current proportional to the output voltage; and a computing circuit configured to compute the ratio of the value of the output voltage to the value of the input voltage. ### Claim 10 (depends on 6) The power supply device according to claim 6, wherein the switching control is a step-down peak current control including slope compensation. ### Claim 11 A power control method for performing switching control for an output voltage of a power supply device, the power control method comprising: receiving a second reference voltage and a difference between a value of the output voltage and a value of a first reference voltage; comparing the difference with a value of a second reference voltage; receiving an input voltage and the output voltage to adjust the value of the second reference voltage based on a ratio between a value of an input voltage and the value of the output voltage and output an adjusted second reference voltage to be subjected to the comparing as the second reference voltage; and stopping the switching control when a value of the difference is less than or equal to the value of the second reference voltage. ### Claim 12 (depends on 11) The power control method according to claim 11 further comprising increasing the value of the second reference voltage as the ratio of the value of the output voltage to the value of the input voltage approaches 1:1 during the adjusting. ### Claim 13 (depends on 12) The power control method according to claim 12 further comprising wherein increasing the value of the second reference voltage when the value of the input voltage becomes less than or equal to a twofold value of the output voltage during the adjusting. ### Claim 14 (depends on 12) The power control method according to claim 12 further comprising: generating a current proportional to the input voltage; generating a current proportional to the output voltage; and computing the ratio of the value of the output voltage to the value of the input voltage. ### Claim 15 (depends on 11) The power control method according to claim 11 further comprising switch-controlling a step-down peak current and slope compensation. ### Claim 16 (depends on 1) The power supply device according to claim 1, wherein the signal generation circuit includes a comparator that compares the difference with the second reference voltage.