# US 2014/0152285 A1 · Average load current detector for a multi-mode switching converter > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2014/0152285 A1 - Document ID: US20140152285A1 - Status: Published application - Kind: A1 - Application number: 14/096,603 - Filed: 2013-12-04 - Published: 2014-06-05 - Earliest claimed: 2012-12-04 - Assignees: RF Micro Devices, Inc. - Applicants: RF Micro Devices, Inc. - Inventors: Ashraf Rozek - Web page: https://patentgrep.com/patent/US20140152285A1 ## CPC - H02M 3/156: with automatic control of output voltage or current, e.g. switching regulators - H02M 1/0009: {Devices or circuits for detecting current in 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 An average load current detector for a multi-mode switching converter is disclosed. The average load current detector includes a sense voltage generator that generates an average sense voltage that is proportional to an average load current delivered by the multi-mode switching converter. Also included is a duty voltage generator that generates an average duty voltage that is proportional to a duty cycle of a pulse width modulation (PWM) signal that controls switching of the multi-mode switching converter. Further included is a comparator adapted to output a detector signal that indicates an operational mode for the multi-mode switching converter to operate in for predetermined load current ranges. A controller receives the detector signal and in response maintains an efficient energy transfer from one supply voltage level to another by transitioning the multi-mode switching converter from the PWM mode to a pulse frequency modulation (PFM) mode or vice versa if necessary. ## Claims ### Claim 1 An average load current detector for a multi-mode switching converter comprising: a sense voltage generator that generates an average sense voltage that is proportional to an average load current delivered by the multi-mode switching converter; a duty voltage generator that generates an average duty voltage that is proportional to a duty cycle of a pulse width modulation (PWM) signal that controls switching of the multi-mode switching converter; and a comparator adapted to output a detector signal that indicates an operational mode for the multi-mode switching converter to operate in for predetermined load current ranges. ### Claim 2 (depends on 1) The average load current detector for the multi-mode switching converter of claim 1 further comprising a controller adapted to receive the detector signal and transition the multi-mode switching converter from one operation mode to another operation mode based upon a logic state of the detector signal. ### Claim 3 (depends on 2) The average load current detector for the multi-mode switching converter of claim 2 wherein the controller is adapted to switch the multi-mode switching converter from operating in a PWM mode to operating in a pulse frequency modulation (PFM) mode when the detector signal indicates an average load current that is less than a predetermined transition load current set point. ### Claim 4 (depends on 2) The average load current detector for the multi-mode switching converter of claim 2 wherein the controller is adapted to switch the multi-mode switching converter from operating in a PFM mode to operating in to PWM mode when the detector signal indicates an average load current that is greater than a predetermined transition load current set point. ### Claim 5 (depends on 1) The average load current detector for the multi-mode switching converter of claim 1 wherein the sense voltage generator comprises: an amplifier having a non-inverting terminal coupled to a switching output terminal of the multi-mode switching converter; a transistor having a control input coupled to an output of the amplifier; and a sense resistor coupled between an output of the transistor and a common voltage node. ### Claim 6 (depends on 5) The average load current detector for the multi-mode switching converter of claim 5 wherein the common voltage node is ground. ### Claim 7 (depends on 6) The average load current detector for the multi-mode switching converter of claim 6 further including a resistor-capacitor (RC) filter. ### Claim 8 (depends on 7) The average load current detector for the multi-mode switching converter of claim 7 wherein the RC filter comprises a resistor coupled between the output of the transistor and a negative input of the comparator along with a capacitor coupled between the negative input of the comparator to the common voltage node. ### Claim 9 (depends on 1) The average load current detector for the multi-mode switching converter of claim 1 wherein the duty voltage generator comprises a second buffer amplifier having a PWM input, at least one regulated voltage supply input, and an output communicatively coupled to a positive input of the comparator. ### Claim 10 (depends on 9) The average load current detector for the multi-mode switching converter of claim 9 further including a second RC filter. ### Claim 11 (depends on 10) The average load current detector for the multi-mode switching converter of claim 10 wherein the second RC filter comprises a second resistor and a second capacitor coupled in parallel between the positive input of the comparator and a common voltage node. ### Claim 12 (depends on 11) The average load current detector for the multi-mode switching converter of claim 11 wherein the common voltage node is ground. ### Claim 13 (depends on 11) The average load current detector for the multi-mode switching converter of claim 11 wherein the second RC filter comprises a third resistor coupled between the output of the second buffer amplifier and the positive input of the comparator. ### Claim 14 (depends on 9) The average load current detector for the multi-mode switching converter of claim 9 further comprising a voltage regulator for regulating a supply voltage at the at least one regulated voltage supply input of the second buffer amplifier. ### Claim 15 (depends on 1) The average load current detector for the multi-mode switching converter of claim 1 further comprising current sensing circuitry adapted to mirror the average load current to generate a sense load current that is a scaled copy of an instantaneous load current flowing through an output node of the multi-mode switching converter. ### Claim 16 (depends on 15) The average load current detector for the multi-mode switching converter of claim 15 wherein the sense load current is equal to the instantaneous load current divided by a scale factor N that ranges from around about 100 to around about 1000. ### Claim 17 (depends on 15) The average load current detector for the multi-mode switching converter of claim 15 wherein the sense load current is equal to the instantaneous load current divided by a scale factor N that ranges from around about 1000 to around about 5000. ### Claim 18 A method for average load current detection for a multi-mode switching converter comprising: generating an average sense voltage that is proportional to an average load current delivered by the multi-mode switching converter; generating a duty voltage that is proportional to a duty cycle of a PWM signal that controls switching of the multi-mode switching converter; and comparing the average sense voltage to the duty voltage; and generating a detector signal that indicates an operational mode for the multi-mode switching converter to operate in for predetermined load current ranges. ### Claim 19 (depends on 18) The method for average load current detection for the multi-mode switching converter of claim 18 further comprising receiving via a controller the detector signal and transitioning the multi-mode switching converter via the controller from one operation mode to another operation mode based upon a logic state of the detector signal. ### Claim 20 (depends on 19) The method for average load current detection for the multi-mode switching converter of claim 19 wherein switching the multi-mode switching converter via the controller from the one operation mode to the another operation mode based upon the logic state of the detector signal that includes transitioning from operating in a PWM mode to operating in a PFM mode when the logic state of the detector signal indicates an average load current that is less than a predetermined transition load current set point. ### Claim 21 (depends on 19) The method for average load current detection for the multi-mode switching converter of claim 19 wherein switching the multi-mode switching converter via the controller from the one operation mode to the another operation mode based upon the logic state of the detector signal that includes transitioning from operating in a PFM mode to operating in a PWM mode when the logic state of the detector signal indicates an average load current that is greater than a predetermined transition load current set point.