# US 10,284,095 B1 · Method and apparatus for phase current balancing in multi-phase constant on-time buck converter > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,284,095 B1 - Document ID: US10284095B1 - Status: Granted - Kind: B1 - Application number: 16/003,369 - Filed: 2018-06-08 - Granted: 2019-05-07 - Earliest claimed: 2018-02-19 - Assignees: Microchip Technology Incorporated - Applicants: Microchip Technology Incorporated - Inventors: Alexander Mednik; Ioan Stoichita; Surya Talari - Web page: https://patentgrep.com/patent/US10284095B1 ## CPC - H02M 3/1584: {with a plurality of power processing stages connected in parallel} - H02J 3/26: Arrangements for eliminating or reducing asymmetry in polyphase networks - H02M 1/08: Circuits specially adapted for the generation of control voltages for semiconductor devices incorporated in static converters - G05F 1/56: using semiconductor devices in series with the load as final control devices (G05F1/461 takes precedence) - G05F 3/30: Regulators using the difference between the base-emitter voltages of two bipolar transistors operating at different current densities (G05F3/26 takes precedence) - H02J 1/102: being switching converters (H02J1/108, H02J1/12 take precedence) - H02M 1/0003: {Details of control, feedback or regulation circuits} - H02M 1/0009: {Devices or circuits for detecting current in a converter} - 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 - Y02E 40/50: Arrangements for eliminating or reducing asymmetry in polyphase networks - 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) - H02J: ELECTRIC POWER NETWORKS; CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY - G05F: SYSTEMS FOR REGULATING ELECTRIC OR MAGNETIC VARIABLES - Y02B: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS - Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION ## Abstract A multi-phase DC-to-DC buck converter for receiving an input voltage and delivering an output voltage to a load by splitting the load current between a plurality of DC-to-DC buck converter cells. The converter includes a plurality of current sense circuits for sensing current in a respective converter cell, each of the current sense circuits configured to generate a respective current sense signal, an averaging circuit for receiving each of the respective current sense signals and generating an average signal, a plurality of imbalance detector circuits for comparing a respective current sense signal with the average signal and generating a respective current imbalance signal, and a plurality of ON time generators for activating a converter cell for a predetermined time interval and altering the predetermined time interval in accordance with a time integral of a respective current imbalance signal. ## Claims ### Claim 1 A multi-phase DC-to-DC buck converter for receiving an input voltage and delivering an output voltage to a load by splitting the load current between a plurality of DC-to-DC buck converter cells, the converter comprising: a plurality of current sense circuits each configured to sense current in a respective one of the plurality of converter cells, each of the plurality of current sense circuits configured to generate a respective current sense signal; an averaging circuit configured to receive each of the respective current sense signals and generate an average signal; a plurality of imbalance detector circuits each configured to compare a respective current sense signal with the average signal and generate a respective current imbalance signal; and a plurality of ON time generators each configured to activate a respective one of the plurality of converter cells for a predetermined time interval and to alter the predetermined time interval in accordance with a time integral of a respective current imbalance signal. ### Claim 2 (depends on 1) The converter of claim 1, wherein each of the plurality of ON time generators comprises: a source of predetermined current; a timing capacitor configured to integrate a sum of the predetermined current and a respective current imbalance signal and generate a ramp voltage; and a comparator for terminating the altered predetermined time interval upon the ramp voltage exceeding a threshold. ### Claim 3 (depends on 2) The converter of claim 2, wherein the predetermined current is substantially proportional to the input voltage. ### Claim 4 (depends on 2) The converter of claim 2, wherein the threshold is substantially proportional to the output voltage. ### Claim 5 (depends on 2) The converter of claim 2, further comprising a plurality of transconductor circuits, wherein each of the plurality of transconductor circuits is configured to transform a respective current imbalance signal to current. ### Claim 6 (depends on 1) The converter of claim 1, further comprising: a plurality of multiplier-divider circuits, wherein each of the plurality of multiplier-divider circuits is configured to multiply a respective current imbalance signal by a ratio of the input voltage and the output voltage, and to generate a normalized current imbalance signal, wherein a respective one of the plurality of ON time generators alters the predetermined time interval in accordance with a time integral of a respective normalized current imbalance signal. ### Claim 7 (depends on 1) The converter of claim 1, further comprising: a plurality of multiplier circuits, wherein each of the plurality of multiplier circuits is configured to multiply a respective current imbalance signal by a duty cycle of a respective one of the plurality of DC-to-DC buck converter cells and to generate a normalized current imbalance signal, wherein a respective one of the plurality of ON time generators alters the predetermined time interval in accordance with a time integral of a respective normalized current imbalance signal. ### Claim 8 (depends on 6) The converter of claim 6, wherein each of the plurality of multiplier-divider circuits includes a corresponding transconductor circuit, wherein each corresponding transconductor circuit is configured to transform a respective current imbalance signal to current. ### Claim 9 A method in a multi-phase DC-to-DC buck converter for receiving an input voltage and delivering an output voltage to a load by splitting the load current between a plurality of DC-to-DC buck converter cells, the method comprising: sensing current in a respective one of the plurality of converter cells and generating a respective current sense signal; receiving each of the respective current sense signals and generating an average signal; comparing a respective current sense signal with the average signal and generating a respective current imbalance signal; and activating a respective one of the plurality of converter cells for a predetermined time interval and altering the predetermined time interval in accordance with a time integral of a respective current imbalance signal. ### Claim 10 (depends on 9) The method of claim 9, further comprising: integrating a sum of a predetermined current and a respective current imbalance signal and generating a ramp voltage; and terminating the altered predetermined time interval upon the ramp voltage exceeding a threshold. ### Claim 11 (depends on 10) The method of claim 10, wherein the predetermined current is substantially proportional to the input voltage. ### Claim 12 (depends on 10) The method of claim 10, wherein the threshold is substantially proportional to the output voltage. ### Claim 13 (depends on 10) The method of claim 10, further comprising transforming a respective current imbalance signal to current. ### Claim 14 (depends on 9) The method of claim 9, further comprising: multiplying a respective current imbalance signal by a ratio of the input voltage and the output voltage to generate a normalized current imbalance signal; and altering the predetermined time interval in accordance with a time integral of a respective normalized current imbalance signal. ### Claim 15 (depends on 9) The method of claim 9, further comprising: multiplying a respective current imbalance signal by a duty cycle of a respective one of the plurality of DC-to-DC buck converter cells to generate a normalized current imbalance signal; and altering the predetermined time interval in accordance with a time integral of a respective normalized current imbalance signal. ### Claim 16 A multi-phase DC-to-DC buck converter for receiving an input voltage and delivering an output voltage to a load by splitting the load current between a plurality of DC-to-DC buck converter cells, the converter comprising: a plurality of current sense circuits each configured to sense current in a respective one of the plurality of converter cells, each of the plurality of current sense circuits configured to generate a respective current sense signal; an averaging circuit configured to receive each of the respective current sense signals and generate an average signal; a plurality of imbalance detector circuits each configured to compare a respective current sense signal with the average signal and generate a respective current imbalance signal; a plurality of transconductor circuits, wherein each of the plurality of transconductor circuits is configured to transform a respective current imbalance signal to current; a plurality of multiplier-divider circuits, wherein each of the plurality of multiplier-divider circuits is configured to multiply a respective current imbalance signal by a ratio of the input voltage and the output voltage, and to generate a normalized current imbalance signal; and a plurality of ON time generators each configured to activate a respective one of the plurality of converter cells for a predetermined time interval and to alter the predetermined time interval in accordance with a time integral of a respective normalized current imbalance signal; each of the ON time generators comprising: a source of predetermined current; a timing capacitor configured to integrate a sum of the predetermined current and a respective current imbalance signal and generate a ramp voltage; and a comparator for terminating the altered predetermined time interval upon the ramp voltage exceeding a threshold. ### Claim 17 A multi-phase DC-to-DC buck converter for receiving an input voltage and delivering an output voltage to a load by splitting the load current between a plurality of DC-to-DC buck converter cells, the converter comprising: a plurality of current sense circuits each configured to sense current in a respective one of the plurality of converter cells, each of the plurality of current sense circuits configured to generate a respective current sense signal; an averaging circuit configured to receive each of the respective current sense signals and generate an average signal; a plurality of imbalance detector circuits each configured to compare a respective current sense signal with the average signal and generate a respective current imbalance signal; a plurality of transconductor circuits, wherein each of the plurality of transconductor circuits is configured to transform a respective current imbalance signal to current; a plurality of multiplier circuits, wherein each of the plurality of multiplier circuits is configured to multiply a respective current imbalance signal by a duty cycle of a respective one of the plurality of DC-to-DC buck converter cells, and to generate a normalized current imbalance signal; and a plurality of ON time generators each configured to activate a respective one of the plurality of converter cells for a predetermined time interval and to alter the predetermined time interval in accordance with a time integral of a respective normalized current imbalance signal; each of the ON time generators comprising: a source of predetermined current; a timing capacitor configured to integrate a sum of the predetermined current and a respective current imbalance signal and generate a ramp voltage; and a comparator for terminating the altered predetermined time interval upon the ramp voltage exceeding a threshold.