# US 10,122,259 B2 · Over power protection for power converter > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,122,259 B2 - Document ID: US10122259B2 - Status: Granted - Kind: B2 - Application number: 15/042,357 - Filed: 2016-02-12 - Published: 2017-03-16 - Granted: 2018-11-06 - Earliest claimed: 2015-09-16 - Assignees: Semiconductor Components Industries, LLC - Applicants: Semiconductor Components Industries, LLC - Inventors: Vaclav Drda; Roman Stuler - Web page: https://patentgrep.com/patent/US10122259B2 ## CPC - H02M 1/32: Means for protecting converters other than automatic disconnection - H02M 3/3376: {with automatic control of output voltage or current} - H02M 1/0012: {Control circuits using digital or numerical techniques (in DC/DC converters H02M3/157, H02M3/33515; in DC-AC converters H02M7/53873)} - H02M 1/0058: {by employing soft switching techniques, i.e. commutation of transistors when applied voltage is zero or when current flow is zero (using an auxiliary actively switched resonant commutation circuit connected to an intermediate DC voltage or between two push-pull branches of an inverter bridge H02M7/4811; in resonant inverters H02M7/4815; in inverters operating from a resonant DC source H02M7/4826)} - H02M 3/157: with digital control - H02M 3/33515: {with digital control} - H02M 7/529: using digital control - 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 conversion circuit is provided. A power level of the power conversion circuit is determined by taking a first sample of a voltage potential of a resonant capacitor at a first time. A second sample of the voltage potential of the resonant capacitor voltage is taken at a second time. An electric current is determined based on the first sample and second sample. ## Claims ### Claim 1 A power conversion circuit, comprising: an average current circuit including an input coupled for receiving a sampling signal representative of a current through a primary winding, wherein the average current circuit measures the sampling signal at a first time and a second time; a power level circuit including a first input coupled to an output of the average current circuit and a second input coupled for receiving an input voltage of the power conversion circuit to determine an input power of the power conversion circuit as a product of the input voltage and a difference between the measurements of the sampling signal at the first time and second time; a first amplifier including a first input coupled for receiving a power reference and a second input coupled to an output of the power level circuit; a variable feedback clamp including a control input coupled to an output of the first amplifier; and a second amplifier including a first input coupled for receiving the sampling signal and a second input coupled to the variable feedback clamp and further coupled for receiving a feedback signal of the power conversion circuit. ### Claim 2 (depends on 1) The power conversion circuit of claim 1, further including: a first power transistor including a first conduction terminal coupled for receiving the input voltage, a second conduction terminal coupled to the primary winding, and a control input coupled to an output of the second amplifier; and a second power transistor including a first conduction terminal coupled to the second conduction terminal of the first transistor, a second conduction terminal coupled to a ground terminal, and a control input coupled to the output of the second amplifier. ### Claim 3 (depends on 2) The power conversion circuit of claim 2, further including a driver logic circuit including an input coupled to the output of the second amplifier, a first output coupled to the control input of the first power transistor, and a second output coupled to the control input of the second power transistor. ### Claim 4 (depends on 1) The power conversion circuit of claim 1, further including a voltage offset circuit coupled between the sampling signal and the first input of the second amplifier. ### Claim 5 (depends on 1) The power conversion circuit of claim 1, further including: a first circuit node adapted for coupling to the primary winding of the power conversion circuit; a resonant capacitor coupled between the first circuit node and a ground terminal; a first capacitor coupled between the first circuit node and a second circuit node; and a second capacitor coupled between the second circuit node and ground terminal, wherein the second circuit node provides the sampling signal. ### Claim 6 (depends on 5) The power conversion circuit of claim 5, further including a resistor coupled between the second circuit node and the ground terminal. ### Claim 7 A power conversion circuit, comprising: an average current circuit including an input coupled for receiving a sampling signal representative of a current through a primary winding, wherein the average current circuit measures the sampling signal at a first time and a second time; and a power level circuit including a first input coupled to an output of the average current circuit and a second input coupled for receiving an input voltage of the power conversion circuit to determine an input power of the power conversion circuit as a product of the input voltage and a difference between the measurements of the sampling signal at the first time and second time. ### Claim 8 (depends on 7) The power conversion circuit of claim 7, further including a first amplifier including a first input coupled for receiving a power reference and a second input coupled to an output of the power level circuit. ### Claim 9 (depends on 8) The power conversion circuit of claim 8, further including: a variable feedback clamp including a control input coupled to an output of the first amplifier; and a second amplifier including a first input coupled for receiving the sampling signal and a second input coupled to the variable feedback clamp and further coupled for receiving a feedback signal of the power conversion circuit. ### Claim 10 (depends on 9) The power conversion circuit of claim 9, further including: a first power transistor including a first conduction terminal coupled for receiving the input voltage, a second conduction terminal coupled to the primary winding, and a control input coupled to an output of the second amplifier; and a second power transistor including a first conduction terminal coupled to the second conduction terminal of the first transistor, a second conduction terminal coupled to a ground terminal, and a control input coupled to the output of the second amplifier. ### Claim 11 (depends on 10) The power conversion circuit of claim 10, further including a driver logic circuit including an input coupled to the output of the second amplifier, a first output coupled to the control input of the first power transistor, and a second output coupled to the control input of the second power transistor. ### Claim 12 (depends on 9) The power conversion circuit of claim 9, further including a voltage offset circuit coupled between the sampling signal and the first input of the second amplifier. ### Claim 13 (depends on 7) The power conversion circuit of claim 7, further including: a first circuit node adapted for coupling to the primary winding of the power conversion circuit; a resonant capacitor coupled between the first circuit node and a ground terminal; a first capacitor coupled between the first circuit node and a second circuit node; and a second capacitor coupled between the second circuit node and ground terminal, wherein the second circuit node provides the sampling signal. ### Claim 14 A method of determining an input power for a power conversion circuit, comprising: measuring a sampling signal representative of a current through a primary winding at a first time and a second time; and determining the input power as a product of an input voltage of the power conversion circuit and a difference between the measurements of the sampling signal at the first time and second time. ### Claim 15 (depends on 14) The method of claim 14, further including comparing the determined input power and a power reference. ### Claim 16 (depends on 15) The method of claim 15, further including clamping a feedback signal of the power conversion circuit in response to comparing the determined input power and the power reference. ### Claim 17 (depends on 16) The power conversion circuit of claim 16, further including comparing the sampling signal to the clamped feedback signal. ### Claim 18 (depends on 17) The power conversion circuit of claim 17, further including controlling a power transistor in response to comparing the sampling signal to the clamped feedback signal. ### Claim 19 (depends on 14) The method of claim 14, further including sensing the current through the primary winding as a voltage across a resonant capacitor. ### Claim 20 (depends on 19) The method of claim 19, further including dividing down the voltage across the resonant capacitor as the sampling signal.