# US 2017/0288662 A1 · System and Method for a High-Side Power Switch > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2017/0288662 A1 - Document ID: US20170288662A1 - Status: Published application - Kind: A1 - Application number: 15/087,342 - Filed: 2016-03-31 - Published: 2017-10-05 - Earliest claimed: 2016-03-31 - Assignees: Infineon Technologies AG - Applicants: Infineon Technologies AG - Inventors: Christian Djelassi; Alexander Mayer; Robert Illing - Web page: https://patentgrep.com/patent/US20170288662A1 ## CPC - H03K 17/687: the devices being field-effect transistors - H03K 17/08122: {in field-effect transistor switches} - H03K 17/0822: {in field-effect transistor switches} - H03K 17/162: {without feedback from the output circuit to the control circuit} - H03K 2217/0063: High side switches, i.e. the higher potential [DC] or life wire [AC] being directly connected to the switch and not via the load - 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 system and method for a high-side power switch includes a gate driver configured to be coupled to a power switch, a voltage measurement circuit configured to be coupled directly to the power switch, a switch monitoring circuit configured to be coupled to the power switch, the switch monitoring circuit configured to measure an output current of the power switch, a current limitation circuit coupled to the gate driver and the switch monitoring circuit, the current limitation circuit configured to regulate gate-source voltage of the gate driver when the output current exceeds a threshold value, and a controller coupled to the current limitation circuit and the voltage measurement circuit, the controller configured to determine a mode of operation according to a startup voltage measured by the voltage measurement circuit during a startup sequence, the controller further configured to provide the threshold value to the current limitation circuit according to the mode of operation and a switch voltage measured by the voltage measurement circuit ## Claims ### Claim 1 A device comprising: a gate driver configured to be coupled to a power switch; a voltage measurement circuit configured to be coupled directly to the power switch; a switch monitoring circuit configured to be coupled to the power switch, the switch monitoring circuit configured to measure an output current of the power switch; a current limitation circuit coupled to the gate driver and the switch monitoring circuit, the current limitation circuit configured to regulate gate-source voltage of the gate driver when the output current exceeds a threshold value; and a controller coupled to the current limitation circuit and the voltage measurement circuit, the controller configured to determine a mode of operation according to a startup voltage measured by the voltage measurement circuit during a startup sequence, the controller further configured to provide the threshold value to the current limitation circuit according to the mode of operation and a switch voltage measured by the voltage measurement circuit. ### Claim 2 (depends on 1) The device of claim 1, wherein the current limitation circuit is further configured to disable the gate driver when regulating the gate-source voltage of the gate driver. ### Claim 3 (depends on 1) The device of claim 1, wherein the threshold value is computed by the controller according to a sum of a continuous threshold and a discrete threshold, the continuous threshold being inversely proportion to the switch voltage, the discrete threshold being a first value when the switch voltage exceeds the startup voltage and a second value when the startup voltage exceeds the switch voltage, the second value being greater than the first value. ### Claim 4 (depends on 3) The device of claim 3, wherein the continuous threshold has a maximum value, and wherein the discrete threshold includes a hysteresis. ### Claim 5 (depends on 1) The device of claim 1, wherein the controller comprises: a voltage comparator configured to generate a control current according to the switch voltage measured by the voltage measurement circuit; and a latch configured to store a startup current according to the startup voltage measured during the startup sequence, the latch configured to provide the threshold value according to whether the control current exceeds the startup current. ### Claim 6 (depends on 5) The device of claim 5, wherein the controller further comprises: a current source coupled to the latch, the current source configured to deliver the threshold value from the latch. ### Claim 7 (depends on 1) The device of claim 1, further comprising: a logic circuit coupled to the gate driver and the controller, the logic circuit configured to restart the controller when the current limitation circuit regulates the gate driver. ### Claim 8 (depends on 7) The device of claim 7, wherein restarting the controller comprises determining the mode of operation according to a second startup voltage measured by the voltage measurement circuit during the restart. ### Claim 9 (depends on 1) The device of claim 1, further comprising the power switch. ### Claim 10 (depends on 9) The device of claim 9, wherein the power switch, the gate driver, the voltage measurement circuit, the switch monitoring circuit, the current limitation circuit, and the controller are disposed on a semiconductor substrate. ### Claim 11 (depends on 1) The device of claim 1, wherein the current limitation circuit is a comparator. ### Claim 12 A method comprising: storing a startup drain-source voltage of a power switch during a startup sequence; measuring a drain-source voltage of the power switch directly at a source terminal and a drain terminal of the power switch; producing a first threshold value as a continuous function of the measured drain-source voltage; producing a second threshold value as a discrete function of the measured drain-source voltage; measuring an output value of the power switch; and disabling the power switch when the output value of the power switch exceeds one of the first threshold value or the second threshold value. ### Claim 13 (depends on 12) The method of claim 12, further comprising: providing a combined threshold value, the combined threshold value being the first threshold value when the measured drain-source voltage is less than the startup drain-source voltage, the combined threshold value being a sum of the first threshold value and the second threshold value when the measured drain-source voltage is greater than the startup drain-source voltage, wherein the power switch is disabled when the output value of the power switch exceeds the combined threshold value, and wherein the combined threshold value is limited to a maximum threshold value. ### Claim 14 (depends on 12) The method of claim 12, wherein the output value of the power switch is an output impedance. ### Claim 15 (depends on 12) The method of claim 12, wherein the output value of the power switch is an output current. ### Claim 16 (depends on 12) The method of claim 12, wherein storing the startup drain-source voltage of the power switch during the startup sequence comprises: measuring an operating temperature of the power switch; and filtering the stored startup drain-source voltage according to the operating temperature. ### Claim 17 (depends on 16) The method of claim 16, wherein filtering the stored startup drain-source voltage comprises reducing the stored startup drain-source voltage when the operating temperature exceeds a threshold. ### Claim 18 (depends on 16) The method of claim 16, further comprising filtering the stored startup drain-source voltage according to measured electromagnetic interference. ### Claim 19 A device comprising: a switch monitoring circuit configured to be coupled to a power switch, the switch monitoring circuit configured to produce a signal proportional to a measured value of the power switch, the switch monitoring circuit configured to provide a first cutoff threshold for the power switch; a filter coupled to the switch monitoring circuit and configured to filter the signal and produce a filtered signal; a latch coupled to the filter and configured to be coupled to a reset line, the latch configured to store the filtered signal in response to an assertion of the reset line; and a current source coupled to the latch and the switch monitoring circuit, the current source configured to provide a second cutoff threshold for the power switch when the signal exceeds the filtered signal stored in the latch. ### Claim 20 (depends on 19) The device of claim 19, wherein the filter comprises a temperature sensor, and wherein producing the filtered signal comprises reducing the signal when a temperature measured by the temperature sensor exceeds a threshold. ### Claim 21 (depends on 19) The device of claim 19, wherein the measured value of the power switch is a source-drain voltage of the power switch, and wherein the switch monitoring circuit is directly coupled to a source terminal and a drain terminal of the power switch. ### Claim 22 (depends on 19) The device of claim 19, further comprising the power switch. ### Claim 23 (depends on 22) The device of claim 22, wherein the power switch is disabled when the measured value of the power switch exceeds a sum of the first cutoff threshold and the second cutoff threshold, wherein the sum is limited to a maximum value. ### Claim 24 (depends on 23) The device of claim 23, wherein the measured value of the power switch is one of resistance or current produced by the power switch.