# US 7,746,050 B2 · Method and apparatus for controlling the maximum output power of a power converter > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 7,746,050 B2 - Document ID: US7746050B2 - Status: Granted - Kind: B2 - Application number: 12/058,539 - Filed: 2008-03-28 - Published: 2008-10-09 - Granted: 2010-06-29 - Earliest claimed: 2007-04-06 - Assignees: Power Integrations, Inc. - Inventors: Alex B. Djenguerian; Erdem Bircan - Web page: https://patentgrep.com/patent/US7746050B2 ## CPC - H02M 3/33523: {with galvanic isolation between input and output of both the power stage and the feedback loop} - G05F 1/66: Regulating electric power - H02M 1/32: Means for protecting converters other than automatic disconnection - H02M 1/0009: {Devices or circuits for detecting current in a converter} - 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) - G05F: SYSTEMS FOR REGULATING ELECTRIC OR MAGNETIC VARIABLES ## Abstract A controller for a power converter is disclosed. An example circuit controller according to aspects of the present invention includes an input voltage sensor to be coupled to receive an input signal representative of an input voltage of the power converter. A current sensor is also included and is to be coupled to sense a current flowing in a power switch. A drive signal generator is to be coupled to drive the power switch into an on state for an on time period and an off state for an off time period. The controller is coupled to adjust a switching cycle period of the power switch to be proportional to a value of the input signal multiplied by a time period. The time period is the time it takes for the current flowing in the power switch to change between two current values when the power switch is in the on state. ## Claims ### Claim 1 A controller for a power converter, comprising: an input voltage sensor to be coupled to receive an input signal representative of an input voltage of the power converter; a current sensor to be coupled to sense a current flowing in a power switch; and a drive signal generator to be coupled to drive the power switch into an on state for an on time period and an off state for an off time period, wherein the drive signal generator is coupled to adjust a switching cycle period of the power switch to be proportional to a value of the input signal multiplied by a time it takes the current flowing in the power switch to change between two current values when the power switch is in the on state. ### Claim 2 (depends on 1) The controller for a power converter of claim 1, wherein one of the two current values is substantially zero. ### Claim 3 (depends on 1) The controller for a power converter of claim 1, wherein one of the two current values is a protective current limit value. ### Claim 4 (depends on 1) The controller for a power converter of claim 1, wherein the input signal is a voltage. ### Claim 5 (depends on 1) The controller for a power converter of claim 1, wherein the input signal is a current signal representative of the input voltage of the power converter. ### Claim 6 (depends on 1) The controller for a power converter of claim 1, wherein the switching cycle period of the power switch is responsive to changes in an inductance of an energy transfer element of the power converter. ### Claim 7 (depends on 1) The controller for a power converter of claim 1 further comprising an oscillator circuit coupled to provide a signal to the drive signal generator. ### Claim 8 (depends on 7) The controller for a power converter of claim 7 further comprising a timing and multiplier circuit coupled to process an output of the current sensor and an output of the input voltage sensor, wherein the oscillator circuit is coupled to be responsive to the timing and multiplier circuit. ### Claim 9 A controller for a power converter, comprising: an input voltage sensor to be coupled to receive an input signal representative of an input voltage of the power converter; a current sensor to be coupled to sense a current flowing in a power switch; and a drive signal generator to be coupled to drive the power switch into an on state for an on time period and an off state for an off time period, wherein the drive signal generator is coupled to adjust a duty cycle of the power switch to be proportional to a value of the input signal multiplied by a time it takes the current flowing in the power switch to change between two current values when the power switch is in the on state. ### Claim 10 (depends on 9) The controller for a power converter of claim 9, wherein one of the two current values is substantially zero. ### Claim 11 (depends on 9) The controller for a power converter of claim 9, wherein one of the two current values is a protective current limit value. ### Claim 12 (depends on 9) The controller for a power converter of claim 9 further comprising an oscillator circuit coupled to provide signal to the drive signal generator. ### Claim 13 (depends on 12) The controller for a power converter of claim 12 further comprising a timing and multiplier circuit coupled to process an output of the current sensor and an output of the input voltage sensor, wherein the oscillator circuit is coupled to be responsive to the timing and multiplier circuit. ### Claim 14 A controller for a power converter, comprising: an input voltage sensor to be coupled to receive an input signal representative of an input voltage of the power converter; a current sensor to be coupled to sense a current flowing in a power switch; and a drive signal generator to be coupled to drive the power switch into an on state for an on time period and an off state for an off time period, wherein the drive signal generator is coupled to adjust a switching cycle period of the power switch in response to a difference between a time it takes the current flowing in the power switch to change between two current values when the power switch is in the on state and a control time period. ### Claim 15 (depends on 14) The controller for a power converter of claim 14, wherein one of the two current values is substantially zero. ### Claim 16 (depends on 14) The controller for a power converter of claim 14, wherein one of the two current values is a protective current limit value. ### Claim 17 (depends on 14) The controller for a power converter of claim 14, wherein the controller is coupled to increase the switching cycle period of the power switch if the time it takes the current flowing in the power switch to change between the two current values when the power switch is in the on state is greater than the control time period. ### Claim 18 (depends on 14) The controller for a power converter of claim 14, wherein the controller is coupled to decreased the switching cycle period of the power switch if the time it takes the current flowing in the power switch to change between the two current values when the power switch is in the on state is less than the control time period. ### Claim 19 (depends on 14) The controller for a power converter of claim 14 further comprising an oscillator circuit coupled to generate a signal coupled to be received by the drive signal generator. ### Claim 20 (depends on 19) The controller for a power converter of claim 19 further comprising a timing and multiplier circuit coupled to process an output of the current sensor and an output of the input voltage sensor, wherein the oscillator circuit is coupled to be responsive to the timing and multiplier circuit. ### Claim 21 A method of controlling a power converter, comprising: switching a power switch between an on state and an off state; sensing an input signal representative of an input voltage of the power converter; sensing a current flowing in the power switch; and adjusting a switching cycle period of the power switch to be proportional to a value of the input signal multiplied by a time it takes the current flowing in the power switch to change between two current values when the power switch is in the on state. ### Claim 22 (depends on 21) The method of controlling the power converter of claim 21, further comprising determining a time it takes the current flowing in the power switch to change from substantially zero to a second one of the two current values. ### Claim 23 (depends on 21) The method of controlling the power converter of claim 21, further comprising determining a time it takes for the current flowing in the power switch to change from a first one of the two current values to a protective current limit value. ### Claim 24 (depends on 21) The method of controlling the power converter of claim 21, wherein sensing the input signal representative of the input voltage of the power converter comprises sensing a voltage. ### Claim 25 (depends on 21) The method of controlling the power converter of claim 21, wherein sensing the input signal representative of the input voltage of the power converter comprises sensing a current during a period when the power switch is in the on state.