# US 11,309,785 B2 · Control circuit for controlling a power switch and associated control method > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,309,785 B2 - Document ID: US11309785B2 - Status: Granted - Kind: B2 - Application number: 17/134,040 - Filed: 2020-12-24 - Published: 2021-05-20 - Granted: 2022-04-19 - Earliest claimed: 2019-12-27 - Assignees: Shenzhen Kiwi Instruments Corporation - Applicants: Shenzhen Kiwi Instruments Corporation - Inventors: Xiufeng Yu; Bo Zhang; Weixiang Jin - Web page: https://patentgrep.com/patent/US11309785B2 ## CPC - H02M 1/0025: {Arrangements for modifying reference values, feedback values or error values in the control loop of a converter} - H02M 1/08: Circuits specially adapted for the generation of control voltages for semiconductor devices incorporated in static converters - H02M 1/44: Circuits or arrangements for compensating for electromagnetic interference in converters or inverters - H03K 4/06: having triangular shape - H03K 5/24: the characteristic being amplitude - H03K 17/162: {without feedback from the output circuit to the control circuit} - H02M 3/156: with automatic control of output voltage or current, e.g. switching regulators - 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) - H03K: PULSE TECHNIQUE (measuring pulse characteristics G01R; modulating sinusoidal oscillations with pulses H03C; transmission of digital information H04L; discriminator circuits detecting phase difference between two signals by counting or integrating cycles of oscillation H03D3/04; automatic control, starting, synchronisation or stabilisation of generators of electronic oscillations or pulses where the type of generator is irrelevant or unspecified H03L; coding, decoding or code conversion, in general H03M) ## Abstract A control circuit for controlling a power switch in a SMPS has a signal jittering circuit and a comparing circuit. The signal jittering circuit adds an overlapping signal into a current sensing signal indicative of current flowing through the power switch or into a current threshold signal, wherein the overlapping signal has a first frequency and an enveloping line of the overlapping signal has a second frequency, and wherein the second frequency is lower than the first frequency. The comparing circuit compares the current sensing signal and the current threshold signal, wherein when the current sensing signal is higher than the current threshold signal, the control circuit c turns off the power switch. ## Claims ### Claim 1 A control circuit for controlling an power switch in a Switching Mode Power Supply (SMPS), the control circuit comprising: a signal jittering circuit configured to add an overlapping signal into a current sensing signal indicative of a current flowing through the power switch to update the current sensing signal or into a current threshold signal to update the current threshold signal, wherein the overlapping signal has a first frequency and an enveloping line of the overlapping signal has a second frequency, and wherein the second frequency is lower than the first frequency; and a comparing circuit configured to compare the current sensing signal with the current threshold signal, wherein when the current sensing signal is higher than the current threshold signal, the control circuit is configured to turn off the power switch. ### Claim 2 (depends on 1) The control circuit of claim 1, further comprising an overlapping signal generating circuit configured to provide the overlapping signal, wherein the overlapping signal generating circuit generates the overlapping signal based on a first control signal and a second control signal, and wherein the first control signal corresponds to the first frequency and the second control signal corresponds to the second frequency. ### Claim 3 (depends on 2) The control circuit of claim 2, wherein the first control signal has the first frequency and the second control signal has the second frequency. ### Claim 4 (depends on 2) The control circuit of claim 2, wherein the first control signal is in a form of a triangle wave signal corresponding to the first frequency and the second control signal is in a form of a triangle wave signal corresponding to the second frequency. ### Claim 5 (depends on 2) The control circuit of claim 2, wherein the first control signal is in a form of an approximate sine wave signal having a higher frequency and the second control signal is in a form of an approximate sine wave signal having a lower frequency. ### Claim 6 (depends on 1) The control circuit of claim 1, wherein the first frequency is lower than the switching frequency of the power switch. ### Claim 7 (depends on 1) The control circuit of claim 1, wherein the overlapping signal in one first cycle period corresponding to the first frequency is scaled into at least three levels by the switching period of the power switch. ### Claim 8 (depends on 7) The control circuit of claim 7, wherein scaled values among different first cycle periods in one second cycle period corresponding to the second frequency are different. ### Claim 9 (depends on 1) The control circuit of claim 1, further comprising a first control module and a second control module, wherein the first control module is configured to control the overlapping signal to periodically vary at the first frequency, and the second control module is configured to control the enveloping line of the overlapping signal to periodically vary at the second frequency. ### Claim 10 (depends on 9) The control circuit of claim 9, wherein: the first control module comprises a first counter and a first decoder coupled to the first counter configured to assign at least three values to the overlapping signal in a first cycle period corresponding to the first frequency; and the second control module comprises a second counter and a second decoder coupled to the second counter configured to control the enveloping line of the overlapping signal in a second cycle period corresponding to the second frequency. ### Claim 11 (depends on 9) The control circuit of claim 9, further comprising a frequency divider having an input coupled to the first control module and having an output coupled to the second control module. ### Claim 12 (depends on 1) The control circuit of claim 1, wherein when the current flowing through the power switch decreases to zero, the power switch is turned on. ### Claim 13 A control circuit for controlling a power switch in an SMPS, comprising a peak current control circuit configured to turn off the power switch when a current flowing through the power switch exceeds a threshold, and the peak current control circuit further configured to control a peak value of the current to vary at a first frequency and control an enveloping line of the peak value to vary at a second frequency, wherein the second frequency is lower than the first frequency. ### Claim 14 A control method for controlling a power switch in a SMPS, comprising: jittering a current sensing signal indicative of current flowing through the power switch with an overlapping signal or jittering a current threshold signal with the overlapping signal, wherein the overlapping signal varies with a first frequency and an enveloping line of the overlapping signal varies with a second frequency, and wherein the first frequency is higher than the second frequency; and comparing the current sensing signal with the current threshold signal, and turning off the power switch when the current sensing signal is higher than the current threshold signal. ### Claim 15 (depends on 14) The control method of claim 14, wherein step of jittering the current sensing signal or current threshold signal with the overlapping signal comprises: generating the overlapping signal according to a first control signal and a second control signal, and wherein the first control signal corresponds to the first frequency and the second control signal corresponds to the second frequency; and adding the overlapping signal into the current sensing signal or the current threshold signal. ### Claim 16 (depends on 15) The control method of claim 15, wherein the first control signal is in a form of a triangle wave signal having the first frequency and the second control signal is in a form of a triangle wave signal having the second frequency. ### Claim 17 (depends on 15) The control method of claim 15, wherein the first control signal is in a form of a sine wave signal having the first frequency and the second control signal is in a form of a sine wave signal having the second frequency. ### Claim 18 (depends on 14) The control method of claim 14, wherein the first frequency is lower than the switching frequency of the power switch. ### Claim 19 (depends on 14) The method of claim 14, wherein peak current of the power switch has at least three different values in one first cycle period corresponding to the first frequency, and wherein peak current values between each two adjacent first cycle periods are different.