# US 12,768,725 B2 · Method for determining a temperature of a depletion layer of a semiconductor switch, and device > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,768,725 B2 - Document ID: US12768725B2 - Status: Granted - Kind: B2 - Application number: 18/572,285 - Filed: 2022-05-31 - Published: 2024-08-29 - Granted: 2026-10-20 - Earliest claimed: 2021-06-21 - Assignees: Robert Bosch GmbH - Applicants: Robert Bosch GmbH - Inventors: Kanuj Sharma; Ingmar Kallfass - Web page: https://patentgrep.com/patent/US12768725B2 ## CPC - G01K 7/01: using semiconducting elements having PN junctions (G01K7/02, G01K7/16, G01K7/30 take precedence) - G01K 7/427: {Temperature calculation based on spatial modeling, e.g. spatial inter- or extrapolation} - G01K 2217/00: Temperature measurement using electric or magnetic components already present in the system to be measured - G01K: MEASURING TEMPERATURE; MEASURING QUANTITY OF HEAT; THERMALLY-SENSITIVE ELEMENTS NOT OTHERWISE PROVIDED FOR (radiation pyrometry G01J5/00) ## Abstract The invention relates to a method for determining a temperature of a depletion layer of a semiconductor switch (2), wherein a first electrical voltage (VS′S) between a source terminal (S) of the semiconductor switch (2) and a Kelvin source terminal (S′) of the semiconductor switch (2) is monitored at least during a switch-on process of the semiconductor switch (2), and wherein the temperature of the depletion layer is determined in accordance with the first voltage (VS′S). According to the invention, it is monitored whether a temperature-independent first trigger is present; it is monitored whether a temperature-dependent second trigger is present, wherein, if a first voltage (VS′S) exceeding a predefined first threshold value (Vref1) is detected, it is established that the second trigger is present; a first time interval, which begins when the first trigger is detected and ends when the second trigger is detected, is determined; and the temperature of the depletion layer is determined in accordance with the first time interval. ## Claims ### Claim 1 A method for determining a temperature of a depletion layer of a semiconductor switch (2), the method comprising: monitoring a first voltage (VS′S) between a source terminal (S) of the semiconductor switch (2) and a Kelvin source terminal (S′) of the semiconductor switch (2) at least during a switch-on process of the semiconductor switch (2) including determining whether a temperature-independent first trigger is present, and determining whether a temperature-dependent second trigger is present, it being established that the second trigger is present when the first voltage (VS′S) exceeding a predefined first threshold value (Vref1) is detected; determining a first time interval which begins with a detection of the first trigger and ends with a detection of the second trigger; and determining the temperature of the depletion layer as a function of the first time interval and of the first voltage (VS′S), wherein it is established that the first trigger is present when the first voltage (VS′S) falls below a second threshold value, the second threshold value being predefined. ### Claim 2 (depends on 1) The method according to claim 1, wherein a gate driver circuit (5) assigned to the semiconductor switch (2) provides the first trigger. ### Claim 3 (depends on 1) The method according to claim 1, wherein a second voltage (VGS′) is monitored between the gate terminal (G) of the semiconductor switch (2) and the source terminal (S) of the semiconductor switch (2), and the temperature of the depletion layer is determined as a function of the second voltage (VGS′) detected at the end of the first time interval. ### Claim 4 (depends on 1) The method according to claim 1, the method further comprising: monitoring the first voltage (VS′S) during a switch-off process of the semiconductor switch (2) including monitoring whether a temperature-independent third trigger is present, and monitoring whether a temperature-dependent fourth trigger is present, it being established that the fourth trigger is present when the first voltage (VS′S) falls below a predefined third threshold value (Vref3); determining a second time interval which begins with a detection of the third trigger and ends with a detection of the fourth trigger; and determining the temperature of the depletion layer as a function of the second time interval. ### Claim 5 (depends on 4) The method according to claim 4, wherein the gate driver circuit (5) provides the third trigger. ### Claim 6 (depends on 4) The method according to claim 4, wherein it is established as a function of the first voltage (VS′S) that the third trigger is present. ### Claim 7 (depends on 1) The method according to claim 1, wherein an electrical load current (ID) flowing through the semiconductor switch (2) is monitored, and the temperature of the depletion layer is determined as a function of the load current (ID). ### Claim 8 (depends on 1) The method according to claim 1, wherein the temperature of the depletion layer is calculated as a function of at least one coefficient stored in a lookup table. ### Claim 9 (depends on 1) A device for determining a temperature of a depletion layer of a semiconductor switch (2), wherein the device (40) comprises an evaluation unit (15) and a sensor unit (13) for monitoring a first electrical voltage (VS′S) between a source terminal (S) of the semiconductor switch (2) and a Kelvin source terminal (S′) of the semiconductor switch (2), wherein the device (40) is specifically configured to carry out the method according to claim 1. ### Claim 10 (depends on 9) The device according to claim 9, wherein the evaluation unit (15) is designed as a microcontroller (15). ### Claim 11 (depends on 9) The device according to claim 9, wherein the evaluation unit (15) comprises at least one flip-flop circuit (20, 21, 28, 29).