# US 9,520,771 B2 · Power supply and apparatus and method for controlling link voltage control switch > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 9,520,771 B2 - Document ID: US9520771B2 - Status: Granted - Kind: B2 - Application number: 13/239,762 - Filed: 2011-09-22 - Published: 2012-08-09 - Granted: 2016-12-13 - Earliest claimed: 2011-02-08 - Assignees: Fairchild Korea Semiconductor Ltd. - Applicants: Sang Cheol Moon; Young-Bae Park - Inventors: Sang Cheol Moon; Young-Bae Park - Web page: https://patentgrep.com/patent/US9520771B2 ## CPC - H02M 1/4258: {using a single converter stage both for correction of AC input power factor and generation of a regulated and galvanically isolated DC output voltage (H02M1/4241 takes precedence)} - H02M 1/0035: {using burst mode control} - H02M 3/335: using semiconductor devices only - 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 supply includes a rectifier for rectifying an AC line voltage to generate a link voltage, a link capacitor for charging the link voltage, a control switch for controlling charge of the link capacitor, a converter for converting the link voltage to a DC voltage, and a switch controller. When the converter operates in a standby operation mode, the switch controller controls on-off of the control switch through a pulse signal having an on-time determined based on a peak value of a detected AC line voltage. ## Claims ### Claim 1 An apparatus for controlling a control switch for controlling a link voltage of a power supply including a rectifier for rectifying an AC line voltage to generate the link voltage and a converter for converting the link voltage to a DC voltage, comprising: a line voltage detector for detecting the AC line voltage; and an on-time generator for generating a control signal for controlling the control switch through a pulse signal when the converter operates at a standby operation mode, the pulse signal having an on-time determined based on a peak value of a detected AC line voltage from the line voltage detector. ### Claim 2 (depends on 1) The apparatus of claim 1, wherein the larger the peak value is, the smaller the on-time is. ### Claim 3 (depends on 2) The apparatus of claim 2, wherein the on-time is inversely proportional to the peak value. ### Claim 4 (depends on 3) The apparatus of claim 3, wherein the on-time generator comprises: a first comparator for comparing the detected AC line voltage with a first reference signal to generate a first comparison signal; a peak detector for detecting the peak value of the detected AC line voltage; and a pulse generator for determining the on-time based on the peak value detected by the peak detector and generating the pulse signal by using a determined on-time and the first comparison signal. ### Claim 5 (depends on 4) The apparatus of claim 4, wherein the pulse generator comprises: a delay capacitor; a first current source for outputting a constant current; a first switch providing the constant current to the delay capacitor according to the first comparison signal; a second current source for outputting a dependent current, wherein the dependent current is dependent on the detected peak value; a second switch for sinking the dependent current from the delay capacitor according to the first comparison signal; a second comparator for comparing a voltage of the delay capacitor with a second reference voltage to generate a second comparison signal; and an AND gate for performing an AND operation with the second comparison signal and the first comparison signal as inputs. ### Claim 6 (depends on 5) The apparatus of claim 5, wherein the dependent current is proportional to the detected peak value. ### Claim 7 (depends on 6) The apparatus of claim 6, wherein, if a level of the first comparison signal is low, the first switch is turned on so that the delay capacitor is charged through the constant current, and wherein, if the level of the first comparison signal is high, the second switch is turned on so that the delay capacitor is discharged through the dependent current. ### Claim 8 (depends on 7) The apparatus of claim 7, wherein the constant current is larger than the dependent current. ### Claim 9 (depends on 3) The apparatus of claim 3, wherein the on-time generator comprises: a mode instruction signal generator for generating a mode instruction signal; an OR gate for performing an OR operation with the pulse signal and the mode instruction signal to generate a gate signal; and a gate driver for converting the gate signal into the control signal. ### Claim 10 (depends on 9) The apparatus of claim 9, wherein the mode instruction signal generator comprises a hysteresis comparator for comparing a feedback signal having information corresponding to the DC voltage with a mode reference voltage to generate the mode instruction signal. ### Claim 11 A method for controlling a control switch for controlling a link voltage of a power supply including a rectifier for rectifying an AC line voltage to generate the link voltage and a converter for converting the link voltage to a DC voltage, comprising: detecting the AC line voltage; determining an on-time based on a peak value of a detected AC line voltage; and generating a control signal for controlling the control switch through a pulse signal with the on-time when the converter operates in a standby operation mode. ### Claim 12 (depends on 11) The method of claim 11, wherein the on-time is inversely proportional to the peak value. ### Claim 13 (depends on 12) The method of claim 12, wherein generating the control signal comprises: comparing the detected AC line voltage with a first reference signal to generate a first comparison signal; and generating the pulse signal by using the on-time and the first comparison signal. ### Claim 14 (depends on 13) The method of claim 13, wherein generating the control signal further comprises: generating a mode instruction signal; performing an OR operation with the pulse signal and the mode instruction signal as inputs to generate a gate signal; and converting the gate signal into the control signal. ### Claim 15 (depends on 14) The method of claim 14, wherein generating the pulse signal comprises: providing a constant current to a delay capacitor in a first level of the first comparison signal; sinking a dependent current from the delay capacitor in a second level of the first comparison signal wherein the dependent current is proportional to the peak value; comparing a voltage of the delay capacitor with a second reference voltage to generate a second comparison signal; and performing an AND operation with the second comparison signal and the first comparison signal as inputs to generate the pulse signal. ### Claim 16 A power supply, comprising: a rectifier for rectifying an AC line voltage to generate a link voltage; a link capacitor that is charged by the link voltage; a control switch for controlling charge of the link capacitor; a converter for converting the link voltage to a DC voltage; and a switch controller for controlling on-off of the control switch through a pulse signal when the converter operates in a standby operation mode, the pulse signal having an on-time determined based on a peak value of a detected AC line voltage. ### Claim 17 (depends on 16) The power supply of claim 16, wherein the on-time is inversely proportional to the peak value. ### Claim 18 (depends on 17) The power supply of claim 17, wherein the switch controller comprises: a line voltage detector for detecting the AC line voltage; a first comparator for comparing the detected AC line voltage with a first reference signal to generate a first comparison signal; a peak detector for detecting the peak value of the detected AC line voltage; a pulse generator for determining the on-time based on the peak value detected by the peak detector and generating the pulse signal by using a determined on-time and the first comparison signal; a mode instruction signal generator for generating a mode instruction signal; an OR gate for performing an OR operation with the pulse signal and the mode instruction signal to generate a gate signal; and a gate driver for converting the gate signal into the control signal. ### Claim 19 (depends on 18) The power supply of claim 18, wherein the pulse generator comprises: a delay capacitor; a first current source for outputting a constant current; a first switch providing the constant current to the delay capacitor according to the first comparison signal; a second current source for outputting a dependent current, wherein the dependent current is dependent on the detected peak value; a second switch for sinking the dependent current from the delay capacitor according to the first comparison signal; a second comparator for comparing a voltage of the delay capacitor with a second reference voltage to generate a second comparison signal; and an AND gate for performing an AND operation with the second comparison signal and the first comparison signal as inputs. ### Claim 20 (depends on 19) The power supply of claim 19, wherein the mode instruction signal generator comprises: a hysteresis comparator for comparing a feedback signal having information corresponding to the DC voltage with a mode reference voltage to generate the mode instruction signal.