Driver circuit with multifunctional pins for on-line characterization of power switches

Abstract

The invention relates to a driver circuit with multifunctional pins for on-line characterization of a power switch. A driver circuit configured to control a power switch is disclosed. The driver circuit may include: an output pin, wherein the driver circuit is configured to deliver a drive signal from the output pin to the power switch to control turn-on of the power switch; a multifunctional pin; and a state machine configured to define operation of the driver circuit using the multi-function pin, where the state machine is configured to select between a soft turn-off mode, a clamp mode, and an online characterization mode.

Description

Technical Field

[0001] The present disclosure relates to driver circuits for controlling power switches, and more particularly to techniques and driver circuits for measuring characteristics of power switches. Background Art

[0002] Power switches are used in various applications to control the power delivered to a load. As an example, the power switch may include a field effect transistor (FET), a bipolar junction transistor (BJT), a gallium nitride (GaN) switch, or a silicon carbide (SiC) switch, or may include a silicon controlled rectifier (SCR). Examples of FETs may include, but are not limited to, junction field effect transistors (JFETs), metal oxide semiconductor FETs (MOSFETs), dual-gate MOSFETs, insulated gate bipolar transistors (IGBTs), any other type of FET, or any combination thereof. Examples of MOSFETs may include, but are not limited to, PMOS, NMOS, DMOS, or any other type of MOSFET, or any combination thereof. MOSFETs may be formed of silicon, gallium nitride, silicon carbide, or other materials. Examples of BJTs may include, but are not limited to, PNP, NPN, heterojunction, or any other type of BJT, or any combination thereof.

[0003] The power switch is typically controlled by a driver circuit via a modulated control signal, such as pulse width modulation (PWM), pulse frequency modulation (PFM), pulse duration modulation, pulse density modulation, or another type of modulated control signal. The modulated control signal can be applied to the gate of the power switch to control the on / off of the power switch, thereby controlling the average amount of power delivered to the load through the power switch. The on / off of the power switch effectively chops its power delivery into discrete portions. The average value of the voltage and / or current fed to the load can be controlled by turning the switch on and off at a fast rate. The longer the switch is on compared to the off period, the higher the total power supplied to the load. In many applications, two different power switches are configured in a high-side and low-side configuration, and the on / off of the two power switches is synchronized so that the desired power is delivered to the switch node positioned between the high-side and low-side switches. Summary of the invention

[0004] In general, the present disclosure describes circuits and techniques that facilitate in-line characterization of a power switch. In-line characterization refers to characterization that occurs during field operation of a power switch, i.e., after the power switch is disposed within a vehicle or within another device or system. According to the present disclosure, a driver circuit includes a multi-function pin, which can be used for in-line characterization measurements of the power switch and other power switch control functions, such as soft shutdown or clamping. For example, a current source for a soft shutdown multi-function pin can be reused to facilitate in-line characterization measurements. Moreover, in-line characterization measurements can be performed during the shutdown of the power switch, which can provide differences and advantages over other techniques.

[0005] In some examples, the present disclosure describes a driver circuit configured to control a power switch. The driver circuit may include: an output pin, wherein the driver circuit is configured to transmit a drive signal from the output pin to the power switch to control the turning on of the power switch; a multi-function pin; and a state machine configured to define the operation of the driver circuit using the multi-function pin, wherein the state machine is configured to select between a soft-off mode, a clamping mode, and an online characterization mode.

[0006] In some examples, the present disclosure describes a method of operating a driver circuit for controlling a power switch, the method comprising: delivering a drive signal from an output pin to the power switch to control the turning on of the power switch; and controlling a multi-function pin via a state machine, wherein the state machine is configured to select between a soft-off mode of the power switch, a clamping mode of the power switch, and an online characterization mode of the power switch.

[0007] In some examples, the present disclosure describes a system including: a power switch; a driver circuit configured to control the power switch based on a drive signal; and a processor configured to deliver a control signal to the driver circuit, wherein the control signal defines the drive signal. The driver circuit includes: an output pin, wherein the driver circuit is configured to deliver the drive signal from the output pin to the power switch to control the turning on of the power switch; a multi-function pin; and a state machine configured to define the operation of the driver circuit using the multi-function pin, wherein the state machine is configured to select between a soft-off mode, a clamping mode, and an online characterization mode.

[0008] The details of these and other examples are set forth in the following drawings and description.Other features, objects, and advantages will be apparent from the description and drawings, and from the claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 is a block diagram of an example system including a power switch circuit, a driver circuit, and a controller.

[0010] Figure 2is a block diagram of an example gate driver circuit consistent with one or more examples of the present disclosure.

[0011] Figure 3 is a set of graphs illustrating detection of voltage thresholds associated with power switches.

[0012] Figure 4 is a set of graphs illustrating detection of gate charge parameters associated with power switches.

[0013] Figure 5 is a graph showing determination of the on-time and off-time of a power switch.

[0014] Figure 6 is a graph of gate voltage values ​​measured by an analog-to-digital converter (ADC) at equidistant time stamps that can be used to determine the turn-on delay and turn-off delay of a power switch.

[0015] Figure 7 is a graph of gate voltage values ​​that can be identified by a comparator, where the DESAT function is used for time measurement that can be used to determine the turn-on delay of the power switch.

[0016] Figure 8 is a flow chart illustrating a method consistent with the present disclosure. DETAILED DESCRIPTION

[0017] The present disclosure describes circuits and techniques used by driver circuits in controlling and characterizing power switches. In particular, the present disclosure describes circuits and techniques that facilitate in-line characterization of a power switch, which refers to characterization that occurs during operation of the power switch in the field, i.e., after the power switch is deployed in a vehicle or in another device or system.

[0018] According to the present disclosure, the driver circuit includes a multi-function pin. The driver circuit may also include a state machine to control the operating state of the multi-function pin. The multi-function pin may be used to control functions such as a soft shut-off function or a clamping function. In addition, the multi-function pin may also be used to perform online characterization measurements on a power switch. A current source associated with the multi-function pin may be configured to deliver different current levels to the multi-function pin for different functions. Therefore, the same current source used for the soft shut-off or clamping function may be utilized and used for online characterization measurements without the need for an additional current source. Moreover, the online characterization measurements may be performed during the shutdown period of the power switch, which may provide differences and advantages over other technologies.

[0019] Figure 11 is a block diagram of an example system 100 including a power switch circuit 18, a driver circuit 10, and a controller processor 120. The processor 120 may include a microprocessor or other type of controller circuit configured to control the driver circuit 10. In particular, the processor 120 sends command signals to the driver circuit 10 via the input pin 112. Based on these command signals, the driver circuit 10 sends an on / off signal (e.g., a gate control signal) to the power switch circuit 110 to turn the power switch on or off.

[0020] The driver circuit 10 can control the power switch 110 via a modulation signal on the output pin 114, which can control the on / off of the power switch 110 within the power switch circuit 18. In particular, the driver circuit 10 is configured to deliver a drive signal (e.g., a modulation signal) from the output pin 114 to the power switch 110 to control the on (and off) of the power switch 110. For example, the modulation signal can include a pulse width modulation (PWM) signal, a pulse frequency modulation (PFM) signal, a pulse duration modulation signal, a pulse density modulation signal, or another type of modulation control signal for controlling a power transistor. In normal operation, the signal from the driver circuit 10 via the output pin 114 can be applied to the gate (or other control terminal) of the power switch 110 to control the on / off of the power switch 110, thereby controlling the power delivered to the load ( Figure 1 In the most general sense, the driver circuit 10 may include any type of driver for any type of power switch, such as a high-side switch driver, a low-side switch driver, or any driver used in any circuit arrangement that controls the on / off of one or more power switches.

[0021] The power switch 110 may include a transistor. For example, the power switch 110 may include an insulated gate bipolar transistor (IGBT) or a field effect transistor (FET), such as a metal oxide field effect transistor (MOSFET) or a gallium nitride FET. The MOSFET may be formed in silicon, in which case the MOSFET may be referred to as a silicon MOSFET. Alternatively, the FET may be formed in another semiconductor material, such as silicon carbide (SiC) or gallium nitride (GaN), in which case the FET may be referred to as a SiC MOSFET or a GaN FET.

[0022] The driver circuit 10 may include logic 12 connected to the power switch circuit 18 for performing detection, control and / or monitoring functions. The logic 12 may be implemented in a circuit system. The logic 12 may include a so-called desaturation (DESAT) logic 102 connected to a DESAT detection pin 116. The DESAT logic 102 refers to logic configured to determine whether the power switch 110 in the power switch circuit 18 is operating in a desaturation mode or an overcurrent state. The DESAT detection pin 116 may be configured to receive a signal associated with the power switch 110 (as well as associated with other circuit elements in the power switch circuit), and the DESAT logic 102 may be configured to detect whether the power switch 110 is in a desaturation mode. The desaturation mode defined herein may generally refer to a desaturation state of an IBGT or an overcurrent state of a MOSFET. For example, the DESAT logic 102 may be configured to disable the power switch 110 in response to detecting that the power switch 110 is operating in a desaturation mode. In the desaturation example, to detect whether the power switch is in a desaturation mode, the DESAT logic 102 can be configured to compare the signal amplitude of the signal on the DESAT detection pin 116 to a desaturation threshold. For example, the signal detected on the DESAT detection pin 116 can include a measure of the voltage drop across the power switch 110 within the power switch circuit 18. In some cases, this voltage drop across the power switch 110 can be referred to as a "Vce" voltage, which generally indicates the voltage between the collector and emitter of an IGBT. In the case of a MOSFET, the voltage drop across the power switch 110 detected on the DESAT detection pin 116 refers to the drain to source voltage.

[0023] According to the present disclosure, the driver circuit 10 includes a multi-function pin 118 and a state machine 16, which is configured to define the operation of the driver circuit 10 using the multi-function pin 18. The state machine 16 can be implemented by dedicated hardware or a processing circuit system. In other words, the state machine 16 can be implemented in a circuit system as part of the driver circuit 10. For example, the state machine 16 can configure the driver circuit 10 to operate in a functional mode to functionally control the power switch 110, or to operate in an online characterization mode to perform characterization measurements on the power switch 110. In some examples, the functional mode may include a soft-off mode for turning off the power switch 110 and a clamping mode for clamping the power switch 110. Therefore, the state machine 16 can be configured to configure the driver operation of the multi-function pin 118 between a soft-off mode, a clamping mode, and an online characterization mode.

[0024] The multifunction logic 104 includes a characterization logic 106 configured to perform an online characterization process to measure one or more circuit parameters of the power switch in response to the state machine 16 defining the operation of the multifunction pin 118 for the online characterization mode. For example, the online characterization process performed by the characterization logic 106 may include a measurement of a voltage threshold associated with the power switch during the off phase, wherein the turn-on delay is determined based on the voltage threshold associated with the power switch during the off phase. The turn-on behavior of the power switch 110 may generally reflect the turn-off behavior of the power switch 110, and therefore, the turn-on delay may be determined based on the voltage threshold associated with the power switch during the off phase. Moreover, in some examples, measurements performed during the off phase may provide advantages relative to measurements performed during the on phase. For example, current sources for soft turn-off and clamping functionality may be reused by the characterization logic 106 for the online characterization process, thereby avoiding the need for additional current sources for the online characterization process.

[0025] In some examples, for additional accuracy in the characterization process, the online characterization process performed by the characterization logic 106 can include a first measurement of a voltage threshold associated with the power switch during an on phase and a second measurement of the voltage threshold associated with the power switch during an off phase, wherein the voltage threshold associated with the power switch is defined based on a combination of the first measurement and the second measurement. In this case, two current sources may be required, one for performing the characterization measurement during the on phase and one for performing the characterization measurement during the off phase. Moreover, in some examples, the voltage threshold associated with the power switch 110 can be defined as a function of temperature based on a combination of the first measurement and the second measurement and based on one or more temperature measurements associated with the power switch 110. If on and off measurements are used, the voltage threshold associated with the power switch 110 can be defined based on an average (or another combined indicator) of the first measurement and the second measurement.

[0026] Typically, the online characterization process may include one or more measurements of a gate voltage associated with the power switch 110. Additionally, the online characterization process performed by the characterization logic 106 may include one or more measurements of a delay associated with turning the power switch on or off. In some examples, the online characterization process performed by the characterization logic 106 includes one or more measurements of a gate voltage associated with the power switch 110 during an off phase of the power switch, and the driver circuit 10 (e.g., the characterization logic 106) may be configured to determine a parameter of a delay associated with the power switch 110 during the off phase of the power switch based on the one or more measurements of the gate voltage.

[0027] Moreover, in some examples, the DESAT detection pin 114 can be used in an online characterization process. For example, the driver circuit 10 can include a DESAT detection pin 116 and a comparator ( Figure 1 In this case, the comparator may be configured to perform one or more measurements of the gate voltage associated with the power switch 110, wherein the driver circuit 10 further includes a timer ( Figure 1 ), the timer includes a clock and a counter, the counter being configured to track a delay parameter associated with the power switch, wherein the timer is triggered based on an event detected by a DESAT detection pin 116 of the driver circuit 10.

[0028] In some examples, the driver circuit 10 may include an analog-to-digital converter ( Figure 1 Instead of using a comparator, the analog-to-digital converter can be configured to perform one or more measurements of a gate voltage associated with the power switch. In this example, the driver circuit 10 can include a timer including a clock for identifying equidistant time points at which the ADC performs one or more measurements of the gate voltage.

[0029] In some examples, the online characterization process performed by the characterization logic 106 may include: one or more measurements of a gate voltage associated with the power switch during a turn-off phase of the power switch, and one or more measurements of the gate voltage associated with the power switch during a turn-on phase of the power switch. In this case, the driver circuit 10 (e.g., the characterization logic 106) may determine one or more measurements of a turn-off delay associated with the power switch based on one or more measurements of the gate voltage during the turn-off phase and one or more measurements of the gate voltage during the turn-on phase; and determine one or more measurements of a turn-on delay associated with the power switch based on one or more measurements of the gate voltage during the turn-off phase and one or more measurements of the gate voltage during the turn-on phase. Analog-to-digital converter ( Figure 1114 ) can be configured to perform one or more measurements of a gate voltage associated with the power switch during an on phase and during an off phase; and a timer, including a clock for identifying equidistant time points at which the ADC performs one or more measurements of the gate voltage during the off phase and during the on phase. The circuit parameters may include a delay parameter, and the driver circuit 10 may also be configured to determine a gate charge parameter based on the delay parameter and the current level used on the multi-function pin 118. The driver circuit 10 may also be configured to determine a capacitance associated with the power switch based on the gate charge and the gate voltage. Alternatively, the gate charge and / or capacitance may be determined by the processor 120, and the driver circuit may communicate the measured parameters back to the processor 120 using a digital interface (e.g., via the input pin 112), whereby the driver circuit 10 is configured to output one or more online characterization parameters to the processor 120 in response to operating in an online characterization mode.

[0030] The driver circuit 10 may include one or more current sources connected to the multi-function pin 118. In some examples, the one or more current sources may be configured to define three different current levels on the multi-function pin 118, wherein the first current level is defined for the soft-off mode, the second current level is defined for the clamping mode, and the third current level is defined for the online characterization mode. The state machine 16 may select the correct current level of the multi-function pin 118 for each mode. As an example, the first current level may be approximately 1 ampere, the second current level may be approximately 10 amperes, and the third current level (i.e., for online characterization) may be in the range of 100 microamperes to 1 milliampere. In the soft-off mode, the driver circuit 10 may be configured to use the multi-function pin 118 to turn off the power switch 110 when the power switch is turned on. In the clamping mode, the driver circuit 10 may be configured to use the multi-function pin 118 to ensure that the power switch 110 remains turned off when the power switch 110 is turned off. In the online characterization mode, the driver circuit 10 may be configured to use the multi-function pin 118 to perform one or more measurements of one or more operating characteristics of the power switch 110.

[0031] Figure 2 is a block diagram of an example gate driver circuit 20 consistent with one or more examples of the present disclosure. In some examples, Figure 2 The gate driver circuit 20 may correspond to Figure 1 The gate driver circuit 10 is configured to control the power switch circuit 24. The processor ( Figure 2 Not shown, but in Figure 1 The processor 120 (shown in FIG. 1 ) can send commands from the gate driver circuits 20 , 10 and receive signals (eg, measurements or fault signals).

[0032] The power switch 24 may include a transistor. For example, the power switch 24 may include an IGBT or a FET, such as a MOSFET or a gallium nitride FET. The MOSFET may be formed in silicon, in which case the MOSFET may be referred to as a silicon MOSFET. Alternatively, the FET may be formed in another semiconductor material, such as SiC or GaN, in which case the FET may be referred to as a SiC MOSFET or a GaN FET.

[0033] The driver circuit 20 can be connected via the output pin (T ON Pin 264 and T OFF The modulation signal on the pin 266) controls the power switch 24, which can control the on / off of the power switch 24. In particular, the turn-on circuit 220 can be turned on at T ON Pin 264 transmits a turn-on signal, which passes through R ON Resistor 278 is provided to deliver an appropriate turn-on voltage to the gate of power switch 24. Similarly, shutdown circuit 222 may be provided at T OFF Pin 266 transmits a shutdown signal, which passes through R OFF Resistor 280 is provided to deliver an appropriate turn-off voltage to the gate of power switch 24. Ground pin 270 is connected to a reference voltage and the source / emitter of power switch 24.

[0034] The driver circuit 20 may include logic 22 configured to cause the driver circuit 20 to perform detection, control and / or monitoring functions with respect to the power switch 24. The logic 22 may include so-called desaturation DESAT logic connected to the DESAT detection pin 262. The DESAT logic refers to logic configured to determine whether the power switch is operating in a desaturation mode or an overcurrent state. The DESAT detection pin 262 may be configured to receive a signal associated with the power switch 24 and associated with other external DESAT circuit elements (i.e., DESAT capacitor 272, DESAT resistor 274, and DESAT diode 276) of the power switch circuit. In particular, the DESAT diode 276 is arranged as a reverse biased diode relative to the power switch 24, and the DESAT diode 276 is arranged in series with the DESAT resistor 274. The DESAT capacitor 272 is connected to ground and is arranged in parallel with the DESAT resistor 274 and the DESAT diode 276.

[0035] In this example, the DESAT logic may include a current source enable logic 202 configured to enable a current source 252 for DESAT functionality. The fault generation logic 204 is configured to pass any DESAT fault signals to an external processor. The threshold generator 206 is configured to define a DESAT threshold voltage stored in the charge cell 248 and applied during the DESAT detection process. The clamp enable logic 208 is configured to control the clamp transistor 254 to clamp the voltage on the DESAT pin 262 during the DESAT detection process. The DESAT comparator 246 compares the threshold defined in the threshold generator 206 with the voltage detected on the DESAT pin 262 to determine whether the power switch 24 is operating in a desaturation mode (i.e., desaturation of the IGBT or overcurrent of the MOSFET).

[0036] According to the present disclosure, the driver circuit 20 includes a multi-function pin 268 (labeled as "SAFETY / SENSING PIN") and a state machine 26 configured to define the operation of the driver circuit 20 using the multi-function pin 268. For example, the state machine 26 can configure the driver circuit 20 to operate in a functional mode to functionally control the power switch 24 via the multi-function pin 268, or alternatively, the state machine 26 can configure the driver circuit to operate in an online characterization mode to perform characterization measurements on the power switch 24 via the multi-function pin 268. In some examples, the functional mode can include a soft-off mode controlled by the soft-off logic 210 to turn off the power switch 24. The functional mode can also include a clamping mode controlled by the clamping logic 212 to clamp the power switch 24. The characterization logic 214 is configured to enable the characterization mode using the multi-function pin 268. Thus, the state machine 26 can be configured to select between the soft shutdown mode, the clamping mode, and the online characterization mode via the multi-function pin 268 based on an enable signal from the logic element 210, 212, or 214 (collectively referred to as the multi-function logic 210, 212, 214). For example, the state machine 26 can select the correct current level of the multi-function pin 268 for each mode.

[0037] The multifunction logic 210, 212, 214 includes a characterization logic 214 configured to perform an online characterization process to measure one or more circuit parameters of the power switch in response to the operation of the multifunction pin 268 defined by the state machine 26 for the online characterization mode. For example, the online characterization process performed by the characterization logic 214 may include a measurement of a voltage threshold associated with the power switch during the off phase, wherein the turn-on delay is determined based on the voltage threshold associated with the power switch during the off phase. The turn-on behavior of the power switch 24 may generally reflect the turn-off behavior of the power switch 24, and therefore, the turn-on delay may be determined based on the voltage threshold associated with the power switch during the off phase. Moreover, in some examples, measurements performed during the off phase may provide advantages relative to measurements performed during the on phase. For example, the current source 258 (e.g., at the off voltage Vee2) that may be used for soft turn-off and clamping functionality may be reused by the characterization logic 214 for the online characterization process, thereby avoiding the need for an additional current source for the online characterization process. The additional current source 256 is optional, and in some cases it may be desirable to avoid the additional current source 256 .

[0038] Figure 2 The example of 214 shows an additional current source 256 (again optional). In some examples, for a higher level of accuracy in the characterization process, the online characterization process performed by the characterization logic 214 may include a first measurement of a voltage threshold associated with the power switch during the turn-on phase (using the additional current source 256 operating at the turn-on voltage Vcc2) and a second measurement of the voltage threshold associated with the power switch during the turn-off phase (using the pre-existing current source 258 operating at the turn-off voltage Vee2). In this case, the voltage threshold associated with the power switch 24 is defined based on a combination of the first measurement and the second measurement. In this case, two current sources 256, 258 are required, one for performing the characterization measurement during the turn-on period and one for performing the characterization measurement during the turn-off period. Moreover, in some examples, based on the combination of the first measurement and the second measurement and based on one or more temperature measurements of the temperature sensor 240 associated with the power switch 24, the voltage threshold associated with the power switch 24 can be defined as a function of temperature (e.g., determined by the temperature sensor 240 associated with the power switch 24). If on and off measurements are used, a voltage threshold associated with the power switch 24 may be defined based on an average of the first and second measurements (or another combined indicator).

[0039] Typically, the online characterization process may include one or more measurements of a gate voltage associated with the power switch 24. Additionally, the online characterization process performed by the characterization logic 214 may include one or more measurements of a delay associated with turning the power switch on or off. In some examples, the online characterization process performed by the characterization logic 214 includes one or more measurements of a gate voltage associated with the power switch 24 during an off phase of the power switch. The driver circuit 20 (e.g., the characterization logic 214) may be configured to determine a parameter of a delay associated with the power switch 24 during an off phase of the power switch based on the one or more measurements of the gate voltage.

[0040] Moreover, in some examples, the DESAT detection pin 262 can be used for an online characterization process. For example, the driver circuit 20 can include a measurement unit 242 in the form of a comparator and a timing unit 244 in the form of a clock and a counter. In this case, the measurement unit 242 in the form of a comparator can be configured to perform one or more measurements of the gate voltage associated with the power switch 24, and the timing unit 244 including the clock and the counter can be configured to track the delay parameter associated with the power switch 24, wherein the timing unit 244 is triggered based on an event detected by the DESAT detection pin 262 of the driver circuit 20.

[0041] In some examples, driver circuit 20 may include an analog-to-digital converter (ADC) rather than using a comparator. In this case, measurement unit 242 includes an ADC, and timing unit 244 includes a clock for identifying equidistant time points at which the ADC performs one or more measurements of the gate voltage of power switch 24. Additional details of examples using a comparator and examples using an ADC are provided below when discussing various graphs in the accompanying drawings.

[0042] In some examples, the online characterization process performed by the characterization logic 214 may include: one or more measurements of a gate voltage associated with the power switch during the off phase of the power switch, and one or more measurements of the gate voltage associated with the power switch during the on phase of the power switch. In this case, the driver circuit 20 (e.g., the characterization logic 214) may determine one or more measurements of a turn-off delay associated with the power switch based on one or more measurements of the gate voltage during the off phase and one or more measurements of the gate voltage during the on phase; and determine one or more measurements of a turn-on delay associated with the power switch based on one or more measurements of the gate voltage during the off phase and one or more measurements of the gate voltage during the on phase. The measurement unit 242 in the form of an ADC may be configured to perform one or more measurements of the gate voltage associated with the power switch during the on phase and during the off phase, and the timing unit 244 including a clock may be configured to identify equidistant time points at which the ADC of the measurement unit 242 performs one or more measurements of the gate voltage during the off phase and during the on phase. The circuit parameters may include delay parameters, and in some examples, the driver circuit 20 may include gate charge determination logic 216 configured to determine the gate charge parameter based on the delay parameter and the current level used on the multi-function pin 268. The driver circuit 20 may also be configured to determine the capacitance associated with the power switch based on the gate charge and the gate voltage. Alternatively, the gate charge and / or capacitance may be determined by an external processor, in which case the driver circuit 20 may communicate the measured parameters back to the processor using a digital interface. In this case, the driver circuit 20 may be configured to output one or more online characterization parameters to the processor in response to operating in an online characterization mode.

[0043] In some examples, the current source 258 can be configured to define three different current levels on the multi-function pin 268, where the first current level is defined for the soft shutdown mode, the second current level is defined for the clamping mode, and the third current level is defined for the online characterization mode. As an example, the first current level can be approximately 1 amp, the second current level can be approximately 10 amps, and the third current level (i.e., for online characterization) can be in the range of 100 microamps to 1 milliamps. The state machine 26 can define the correct current level of the current source 258 for the operation of the multi-function pin 268 in different modes. The additional current source 256 (if used) can also define a third current level (i.e., for online characterization), which can be in the range of 100 microamps to 1 milliamps.

[0044] In the soft-off mode, the soft-off logic 210 can be configured to use the multi-function pin 268 to turn off the power switch 24 when the power switch is on. In the clamp mode, the clamp logic 212 can be configured to use the multi-function pin 268 to ensure that the power switch 24 remains off when the power switch 24 is off. In the online characterization mode, the characterization logic 214 can be configured to use the multi-function pin 268 to perform one or more measurements of one or more operating characteristics of the power switch 24.

[0045] It is expected that online characterization of the power switch will help identify and predict problems before they occur. Thus, using online characterization, predictive maintenance of the power switch 24 can be improved, such as alerting of possible power switch problems or trends before a power switch failure occurs, and allowing a replacement power switch to be installed before a problem occurs.

[0046] It is expected that several different independent functions (characterization mode of external switch, soft turn-off, active Miller clamp) can be implemented using shared pins and programmable current sources as well as dedicated state machines for generating the required current values ​​in the current sources and related evaluation circuits.

[0047] The safety shutdown functionality is a desired function in response to a severe fault, where the power switch 24 must be turned off in a safe manner. With other techniques, a safe shutdown can be performed using an independent external resistor via an additional internal clamping stage to the negative voltage rail. The clamping feature clamps the gate in a low impedance path to prevent parasitic turn-on of Miller current generation within the half-bridge topology when the power switch 24 is turned off. With other techniques, the clamping is usually completed by an additional independent clamping stage to Vee2. According to the present disclosure, a configurable current source can be used to measure the characteristics of a power semiconductor by configuring a small current, combining information from the gate timing and the DESAT voltage detector. The technology of the present disclosure can combine three features, requiring only a single current source 258 and a dedicated state machine (i.e., state machine 26) to change the current value of the current source 258 with respect to three different functions. Since the driver circuit 20 never uses these three functions at the same time, this very compact multi-function implementation is possible. The measured characteristics of the power switch 24 can be saved or used in the driver circuit 20, which can send an alert to the processor if a problem is identified, or the driver circuit 20 can send the measurement information back to an external processor to compare the actual measurement results with previous measurements or expectations to determine if there may be a problem. In the event that the driver circuit cannot detect the voltage change on the DESAT pin, the gate shape of the turn-off sequence can be measured during the characterization phase using an internal ADC.

[0048] The disclosed techniques may enable the characterization of a power switch during use within a system. Using the characterization information, the power switch customer may react to the aging process and improve the detectability of predictive maintenance of the power switch within the customer's system. The disclosed techniques provide the opportunity to measure characteristic data of a power switch over its lifetime. Using this, reliability models may be updated based on the measured characteristics and predictive maintenance may be performed before a power switch failure occurs.

[0049] Online characterization refers to the characterization of the power switch when it is used. Online characterization can measure or calculate key technical parameters (such as Vgs threshold, Crss, turn-on delay, turn-off delay, charge or other parameters) during the life of the power switch. Similarly, online characterization can help improve the predictive maintenance of power switches within vehicles or other systems, and as more and more vehicles are directly connected to the cloud (i.e., computer networks), system-level information can be provided. For example, for the safety of the main inverter of the vehicle, predictive maintenance requirements are sometimes desired. Dynamic life control is not possible without updating the characterization of power semiconductor aging. In some examples, online characterization of power switch parameters can enable more efficient parallelization and driving, for example, using configurable current sources.

[0050] The technology of this disclosure uses a combination of three independent functionalities:

[0051] -Soft shutdown

[0052] -Gate / Clamp

[0053] -Online Characterization

[0054] All three of these features are independent and never used at the same time, so all features can be combined into a single pin of the driver circuit. Depending on the operating mode of the driver circuit, the pin can be controlled by an internal state machine. The state machine can define the required current level for each of the three different functionalities via a programmable current source. The state machine can be controlled by an external processor during runtime or during a power-up / power-down procedure.

[0055] In some online characterization parameter identification processes, a first loop can be used to measure the voltage threshold of a power switch, and a second loop can be used to measure the gate-to-source voltage (or collector-to-emitter voltage) as a function of time. During the first loop, a comparator can be triggered, and samples can be stored before and after the trigger event. During the second loop, gate-to-source capacitance, gate-to-drain charge, and on-state capacitance can be determined.

[0056] Figure 3is a collection of graphs illustrating detection of voltage thresholds associated with a power switch.This example may involve initiating a one-time threshold measurement via an external pin or via a digital communication interface such as a serial peripheral interface (SPI). Figure 3 The top curve in FIG32 illustrates the DESAT voltage as a function of time. The voltage threshold (V DESAT The bottom graph 34 is the corresponding gate-to-source voltage Vgs of the power switch. In some examples, the techniques of the present disclosure may use the DESAT pin to identify V DESAT The occurrence of the threshold value is used to determine when to measure the Vgs threshold value 38 associated with the off state. In some examples, as mentioned, the VGS threshold value 36 at the on state may also be used, in which case the Vgs threshold value may be determined based on the average of the Vgs threshold value 38 associated with the off state and the Vgs threshold value 36 at the on state.

[0057] The online characterization process can include using a configurable current source (e.g. Figure 2 The current source 256 of the power supply 242 is charged to change the voltage on the DESAT pin 262 from high to low, which indicates that the power switch threshold is a low value. In some examples, the driver circuit 20 can measure this value using an integrated ADC within the measurement unit 242 (with optional oversampling). Then, a configurable current source (e.g. Figure 2 The current source 258 of the present disclosure is discharged to change DESAT from low to high. The techniques of the present disclosure can use the optional oversampling of the ADC to measure the Vgs threshold. Moreover, these techniques can combine the measurement results with one or more internal or external temperature measurements, such as based on the temperature sensor 240, to obtain a temperature-dependent Vgs measurement.

[0058] The disclosed techniques can provide more accurate measurements based on temperature dependency and based on high and low threshold measurements. The average of the high and low thresholds can be used to more accurately determine the actual Vgs threshold of the power switch based on temperature. In some examples, the disclosed techniques can also compensate for the effects of DESAT timing on the measurements.

[0059] Figure 4 is a collection of graphs illustrating detection of a gate charge parameter associated with a power switch that may be determined as a function of drain voltage 44 and gate voltage 42 over time based on measurements performed. Figure 4Any gate charge parameter "Q" shown can be determined by the gate driver circuit or processor by measuring the gate to source voltage threshold Vth and possibly by identifying the start and end of the Miller plateau. For example, the parameters that can be determined can include the gate to source charge when turned on Qgs1, the gate to drain charge Qgd during the Miller plateau, the switch charge Qsw, the gate charge Qg, and the gate to source charge during the turn-off Qgs2. The gate to source charge Qgs can be determined as the difference between the gate charge Qg and the gate to drain charge Qgd. The gate to source charge can also be determined as the sum of Qgs1 and Qgs2. It can be determined by the gate driver or a processor that receives the measured parameters from the gate driver.

[0060] The gate input terminal (G) of a MOSFET is insulated, so the amount of charge Q seen by the gate is an important characteristic, as Figure 4 As shown and defined, and further explained in Table 1 below:

[0061] Table 1

[0062]

[0063]

[0064] Figure 5 is a graph showing the determination of the on-time and off-time of the power switch. In particular, Figure 5 shows the gate-to-source voltage V GS 52 (eg, input waveform) and the drain-to-source voltage V of the power switch DS 54 Corresponding curve graph (e.g. output waveform) changing with time. on The delay may correspond to V GS The rise time and tr (which is determined by V GS The rise caused by V DS toff delay may correspond to V GS The fall time and t f (This is due to V GS The drop in V DS rise time). Since T on Delay and T off Delays often mimic each other, and in some examples, T off The measured value is T on of measurement and vice versa.

[0065] Figure 6is a graph of gate voltage values ​​measured by the ADC at equidistant time stamps that can be used to determine the turn-on delay and turn-off delay of the power switch. In this example, the power switch 24 is turned off via the multi-function pin 268 and based on the low current provided by the current source 258. The state machine 26 can define the current level for characterizing the process. The measurement unit 242 including the ADC can measure V at equidistant time stamp events. gs The voltage is sampled. Point 62 may define the beginning of the Miller plateau and may be at V gs When the change is less than the threshold change amount (for example, when ΔV gs Similarly, point 64 may define the end of the Miller plateau, and point 64 may be at V gs When the change is greater than the threshold change amount (for example, when ΔV gs Of course, if the ADC uses faster or slower sampling to achieve better accuracy (faster ADC sampling) or lower cost implementation (slower ADC sampling), different values ​​may be used for the expected change and the change at the Miller plateau.

[0066] For example, Figure 6 Techniques for measuring turn-on delay and turn-off delay are shown. In some examples, since the turn-on reflects the turn-off curve after the Miller plateau, the turn-on delay can be measured during the turn-off process.

[0067] according to Figure 6 , the current source 258 can use the multi-function pin 268 to turn off the power switch 24 in a controlled, slow manner to measure all the desired electrical characteristics of the power switch. The switch is turned on and then turned off using a controlled, configurable current source as the ADC samples the turn-off and searches for the trigger point. The delta voltage reduction is defined by two adjacent ADC measurements, which can be compared to define the voltage slope and determine the onset of the Miller plateau.

[0068] Figure 7 is a graph of gate voltage values ​​that can be identified by a comparator, where the DESAT function is used for time measurement, which can be used to determine the turn-on delay of the power switch. In this example, the power switch 24 is turned off via the multi-function pin 268 and based on the low current provided by the current source 258. The state machine 26 can define the current level for characterizing the process. The measurement unit 242 including the comparator can determine the Ton delay Qgs1 by starting or stopping the timer when Vgsth_high occurs based on the measured DESAT signal on the DESAT pin 262. The event at point 72 corresponds to a measure of the Toff delay combined with the Miller plateau (e.g., Toffdel+Tsw).

[0069] exist Figure 7 In the illustrated technique, the DESAT pin 262 monitors the drain to source (or collector to emitter for IBGTs), and this measurement can be used to detect the turning on and off of the power switch. The measurement unit 242 includes a comparator that is configured to start a timer 244 at the beginning of the process and end the timer when the switch turns off after the Miller plateau is detected at the DESAT pin.

[0070] Therefore, using Figure 6 In the example of , the measurement unit 242 includes an ADC, and the timer 244 is a clock that defines the equidistant times at which the ADC should perform its measurements. Figure 7 In an example, the measurement unit 242 includes a comparator and the timer 244 includes a clock and a counter for determining the length of time of the Ton delay after point 72 until Vgs reaches the low threshold value defined by the comparator of the measurement unit 242.

[0071] The gate driver or external processor can then use the measured parameters to calculate the charge (Q) associated with the power switch. Since I = Q / t and the current I is a known value (the current from the current source 258 during the characterization process), when T (turn-on delay or turn-off delay) is measured, the processor or driver circuit can calculate Q as the sum of T and I. The capacitance of the switch can also be determined based on Q and voltage, and these values ​​can be defined based on the temperature measured by the temperature sensor 240 to provide a good characterization of the power switch.

[0072] By using very low currents during the calibration process, the turn-on and turn-off can be slowed down to facilitate easier measurements. Also, as mentioned above, the turn-off can use the existing current source 258, which is already required for soft turn-off and clamping (e.g. at Vee2 for turn-off). The additional current source 256 (at Vcc2 for turn-on) is optional to allow better measurements by combining and using the average of the measurements during turn-on and turn-off.

[0073] In some examples, the present disclosure describes a multi-function pin with an integrated state machine for performing functional operations (clamping and soft shutdown) and characterization operations. In some examples, the present disclosure uses DESAT information changes to measure the voltage threshold of a power switch. The techniques of the present disclosure can be performed at shutdown (utilizing existing current sources required for soft shutdown functionality, or can be completed using switching on and off, in which case the combined information can help compensate for the effects of the DESAT circuit system. The combined information measured at switching on and off can also be combined with internal and external temperature measurements to characterize the device as a function of operating temperature. The parameters measured or determined can include Qgs, Qgd, Tondel, Tsw, and Toffdel.

[0074] In some examples, using off to characterize the power switch can provide advantages over using on. On is primarily defined by the thresholds, temperature, and gm of the external switch components. Off is primarily defined by the internal current source and the capacitive load at the DESAT pin. For this reason, off can be more accurate than on, and as mentioned, a combination of on and off can provide a more accurate characterization measurement than using only on or only off.

[0075] The total gate charge Qg can be measured by integrating the current with a dedicated timer running. In some cases, the measurement of Qgs occurs before and after the threshold to determine Qgs1 and Qgs2. In some examples, the measurement of Qgs2+Qgd may occur in response to a change in DESAT information (e.g., Vdesat_th_low to _DESAT_th_high). The timer start and stop criteria can be performed via ADC measurements. Q (charge) information can also be used to determine capacitance, for example, via a driver circuit or via a processor. For systems without an ADC, a comparator can be used to start and stop the timer based on the determined DESAT.

[0076] Figure 8 is a flow chart illustrating a method consistent with the present disclosure. Figure 8As shown, the driver circuit 10, 20 is configured to drive the power switch 110, 24 (802), such as by delivering a PWM signal to the gate of the power switch 110, 24. The logic 12, 22 of the driver circuit 10, 20 selects an operating mode for the multi-function pin 118, 268. In a first mode (mode 1), the driver circuit 10, 20 uses the multi-function pin 118, 268 to perform a soft shutdown of the power switch 110, 24 (806). For mode 1, the state machine 16, 26 can program the current source 258 to a first current level of approximately 1 ampere. In a second mode (mode 2), the driver circuit 10, 20 uses the multi-function pin 118, 268 to perform a clamping operation on the power switch 110, 24 (808). For mode 2, the state machine 16, 26 can program the current source 258 to a second current level of approximately 10 amperes. In a third mode (Mode 3), the driver circuit 10, 20 performs an online characterization process (810) on the power switch 110, 24 using the multi-function pin 118, 268. For Mode 3, the state machine 16, 26 may program the current source 258 (and optionally the current source 256) to a third current level in the range of 100 microamperes to 1 milliampere.

[0077] The technology described in the present disclosure can be implemented at least in part in circuit systems, hardware, software, firmware or any combination thereof. Such hardware, software and firmware can be implemented in the same device or in separate devices to support the various operations and functions described in the present disclosure. In addition, any of the described units, modules or components can be implemented together or individually as discrete logic but interoperable circuits or devices. The depiction of different features as modules or units is intended to emphasize different functional aspects, and does not necessarily mean that such modules or units must be implemented by separate hardware. On the contrary, the functionality associated with one or more modules or units can be performed by separate hardware or circuits, or integrated in common components or circuits. One or more aspects of the present disclosure may also be performed in software, in which case those aspects of the technology described in the present disclosure may also be implemented or encoded in a computer-readable medium.

[0078] The following numbered aspects demonstrate one or more aspects of the disclosure.

[0079] Item 1: A driver circuit configured to control a power switch, the driver circuit comprising: an output pin, wherein the driver circuit is configured to transmit a drive signal from the output pin to the power switch to control the turning on of the power switch; a multi-function pin; and a state machine configured to define the operation of the driver circuit using the multi-function pin, wherein the state machine is configured to select between a soft shutdown mode, a clamping mode, and an online characterization mode.

[0080] Clause 2: The driver circuit of clause 1, wherein the driver circuit further comprises: a DESAT detection pin configured to receive a signal associated with the power switch; and a DESAT circuit element and DESAT logic configured to detect whether the power switch is in a desaturation mode.

[0081] Clause 3: A driver circuit according to clause 1 or 2, wherein the driver circuit comprises one or more current sources connected to the multi-function pin, wherein the one or more current sources are configured to define three different current levels on the multi-function pin, wherein the first current level is defined for a soft shutdown mode, the second current level is defined for a clamping mode, and the third current level is defined for an online characterization mode.

[0082] Clause 4: The driver circuit of clause 3, wherein the first current level is approximately 1 ampere, wherein the second current level is approximately 10 amperes, and wherein the third current level is in the range of 100 microamperes to 1 milliampere.

[0083] Clause 5: A driver circuit according to any one of clauses 1 to 4, wherein the soft-off mode is configured to turn off the power switch when the power switch is turned on, wherein the clamping mode is configured to ensure that the power switch remains turned off when the power switch is turned off, and wherein the online characterization mode is configured to perform one or more measurements of one or more operating characteristics of the power switch.

[0084] Clause 6: The driver circuit of any of Clauses 1 to 5, wherein the driver circuit is configured to perform an online characterization process to measure one or more circuit parameters of the power switch in response to the state machine selecting an online characterization mode.

[0085] Clause 7: The driver circuit of clause 6, wherein the online characterization process includes a measurement of a voltage threshold associated with the power switch during a turn-off phase, wherein the turn-off delay is determined based on the voltage threshold associated with the power switch during the turn-off phase.

[0086] Clause 8: A driver circuit according to clause 6 or 7, wherein the online characterization process includes a first measurement value of a voltage threshold associated with the power switch during a turn-on phase and a second measurement value of the voltage threshold associated with the power switch during a turn-off phase, wherein the voltage threshold associated with the power switch is defined based on a combination of the first measurement value and the second measurement value.

[0087] Clause 9: The driver circuit of clause 8, wherein a voltage threshold associated with the power switch is defined as a function of temperature based on a combination of the first measurement and the second measurement and based on one or more temperature measurements associated with the power switch.

[0088] Clause 10: The driver circuit of clause 8 or 9, wherein a voltage threshold associated with the power switch is defined based on an average of the first measurement value and the second measurement value.

[0089] Clause 11: The driver circuit of any of Clauses 6 to 10, wherein the online characterization process comprises one or more measurements of a gate voltage associated with the power switch.

[0090] Clause 12: The driver circuit of any of Clauses 6 to 11, wherein the online characterization process includes one or more measurements of delays associated with turning the power switch on or off.

[0091] Clause 13: A driver circuit according to any of clauses 6 to 12, wherein the online characterization process includes one or more measurements of a gate voltage associated with the power switch during a turn-off phase of the power switch, and wherein the driver circuit is configured to determine a parameter of a delay associated with the power switch during the turn-off phase of the power switch based on the one or more measurements of the gate voltage.

[0092] Clause 14: A driver circuit according to clause 13, wherein the driver circuit includes a DESAT detection pin and a comparator configured to perform one or more measurements of a gate voltage associated with the power switch, wherein the driver circuit includes a timer, the timer including an hour hand and a counter, the counter configured to track a delay parameter associated with the power switch, wherein the timer is triggered based on an event detected by the DESAT detection pin of the driver circuit.

[0093] Clause 15: The driver circuit of clause 13, wherein the driver circuit comprises an ADC configured to perform one or more measurements of a gate voltage associated with the power switch.

[0094] Clause 16: The driver circuit of clause 15, wherein the driver circuit comprises a timer comprising a clock for identifying equidistant points in time at which the ADC performs one or more measurements of the gate voltage.

[0095] Clause 17: A driver circuit according to any one of clauses 6 to 16, wherein the online characterization process includes: one or more measured values ​​of a gate voltage associated with the power switch during a turn-off phase of the power switch, and one or more measured values ​​of the gate voltage associated with the power switch during a turn-on phase of the power switch, wherein the driver circuit is configured to: determine one or more measured values ​​of a turn-off delay associated with the power switch based on the one or more measured values ​​of the gate voltage during the turn-off phase and the one or more measured values ​​of the gate voltage during the turn-on phase; and determine one or more measured values ​​of a turn-on delay associated with the power switch based on the one or more measured values ​​of the gate voltage during the turn-off phase and the one or more measured values ​​of the gate voltage during the turn-on phase.

[0096] Item 18: A driver circuit according to item 17, wherein the driver circuit includes: an ADC configured to perform one or more measurements of a gate voltage associated with a power switch during an on-phase and during an off-phase; and a timer including a clock for identifying equidistant time points at which the ADC performs one or more measurements of the gate voltage during the off-phase and during the on-phase.

[0097] Clause 19: The driver circuit of any of clauses 6 to 18, wherein the circuit parameter comprises a delay parameter, and the driver circuit is further configured to determine the gate charge parameter based on the delay parameter and a current level used on the multi-function pin.

[0098] Clause 20: The driver circuit of any of clauses 6 to 19, wherein the driver circuit is further configured to determine a capacitance associated with the power switch based on the gate charge and the gate voltage.

[0099] Clause 21: The driver circuit of any of clauses 6 to 20, wherein the driver circuit comprises a digital interface to the processor, and wherein the driver circuit is configured to output one or more online characterization parameters to the processor in response to operating in the online characterization mode.

[0100] Item 22: A method of operating a driver circuit for controlling a power switch, the method comprising: transmitting a drive signal from an output pin to the power switch to control the turning on of the power switch; and controlling a multi-function pin via a state machine, wherein the state machine is configured to select between a soft-off mode of the power switch, a clamping mode of the power switch, and an online characterization mode of the power switch.

[0101] Item 23: A system comprising: a power switch; a driver circuit configured to control the power switch based on a drive signal; and a processor configured to transmit a control signal to the driver circuit, wherein the control signal defines the drive signal, wherein the driver circuit comprises: an output pin, wherein the driver circuit is configured to transmit the drive signal from the output pin to the power switch to control the turning on of the power switch; a multi-function pin; and a state machine configured to define the operation of the driver circuit using the multi-function pin, wherein the state machine is configured to select between a soft shutdown mode, a clamping mode, and an online characterization mode.

[0102] Clause 24: The system of clause 23, wherein the driver circuit comprises the features of any one of clauses 2-21.

[0103] Various aspects have been described in this disclosure. These and other aspects are within the scope of the following claims.

Claims

1. A driver circuit configured to control a power switch, the driver circuit comprising: an output pin, wherein the driver circuit is configured to transmit a driving signal from the output pin to the power switch to control the turning on of the power switch; Multi-function pins; as well as A state machine is configured to define operation of the driver circuit using the multi-function pin, wherein the state machine is configured to select between a soft-off mode, a clamping mode, and an in-circuit characterization mode.

2. The driver circuit according to claim 1, wherein the driver circuit further comprises: a desaturation detection pin DESAT configured to receive a signal associated with the power switch; as well as The DESAT circuit element and the DESAT logic are configured to detect whether the power switch is in a desaturation mode.

3. The driver circuit of claim 1 , wherein the driver circuit comprises one or more current sources connected to the multi-function pin, wherein the one or more current sources are configured to define three different current levels on the multi-function pin, wherein a first current level is defined for the soft-off mode, a second current level is defined for the clamping mode, and a third current level is defined for the online characterization mode.

4. The driver circuit of claim 3, wherein the first current level is approximately 1 ampere, wherein the second current level is approximately 10 amperes, and wherein the third current level is in the range of 100 microamperes to 1 milliampere.

5. The driver circuit of claim 1 , wherein the soft-off mode is configured to turn off the power switch when the power switch is turned on, wherein the clamping mode is configured to ensure that the power switch remains off when the power switch is turned off, and wherein the online characterization mode is configured to perform one or more measurements of one or more operating characteristics of the power switch. 6 . The driver circuit of claim 1 , wherein the driver circuit is configured to perform an online characterization process to measure one or more circuit parameters of the power switch in response to the state machine selecting the online characterization mode.

7. The driver circuit of claim 6, wherein the online characterization process includes a measurement of a voltage threshold associated with the power switch during a turn-off phase, wherein a turn-off delay is determined based on the voltage threshold associated with the power switch during a turn-off phase.

8. The driver circuit of claim 6 , wherein the online characterization process comprises a first measurement of a voltage threshold associated with the power switch during an on-phase and a second measurement of the voltage threshold associated with the power switch during an off-phase, wherein the voltage threshold associated with the power switch is defined based on a combination of the first measurement and the second measurement.

9. The driver circuit of claim 8, wherein the voltage threshold associated with the power switch is defined as a function of temperature based on the combination of the first measurement and the second measurement and based on one or more temperature measurements associated with the power switch.

10. The driver circuit of claim 8, wherein the voltage threshold associated with the power switch is defined based on an average of the first measurement value and the second measurement value.

11. The driver circuit of claim 6, wherein the online characterization process includes one or more measurements of a gate voltage associated with the power switch.

12. The driver circuit of claim 6, wherein the online characterization process includes one or more measurements of delays associated with turning the power switch on or off.

13. The driver circuit of claim 6, wherein the online characterization process includes one or more measurements of a gate voltage associated with the power switch during an off phase of the power switch, and wherein the driver circuit is configured to determine a parameter of a delay associated with the power switch during the off phase of the power switch based on the one or more measurements of the gate voltage.

14. The driver circuit of claim 13 , wherein the driver circuit comprises a desaturation (DESAT) detection pin and a comparator configured to perform the one or more measurements of a gate voltage associated with the power switch, wherein the driver circuit comprises a timer comprising an hour hand and a counter configured to track a delay parameter associated with the power switch, wherein the timer is triggered based on an event detected by the DESAT detection pin of the driver circuit. 15 . The driver circuit of claim 13 , wherein the driver circuit comprises an analog-to-digital converter (ADC) configured to perform the one or more measurements of a gate voltage associated with the power switch.

16. The driver circuit of claim 15, wherein the driver circuit comprises a timer including a clock for identifying equidistant points in time at which the ADC performs the one or more measurements of the gate voltage.

17. The driver circuit of claim 6, wherein the online characterization process comprises: one or more measurements of a gate voltage associated with the power switch during an off phase of the power switch, and one or more measurements of a gate voltage associated with the power switch during an on-phase of the power switch, The driver circuit is configured as follows: determining one or more measurements of a turn-off delay associated with the power switch based on the one or more measurements of the gate voltage during the turn-off phase and the one or more measurements of the gate voltage during the turn-on phase; as well as Based on the one or more measurements of the gate voltage during the turn-off phase and the one or more measurements of the gate voltage during the turn-on phase, one or more measurements of a turn-on delay associated with the power switch are determined.

18. The driver circuit according to claim 17, wherein the driver circuit comprises: an analog-to-digital converter ADC configured to perform the one or more measurements of a gate voltage associated with the power switch during the on-phase and during the off-phase; as well as A timer includes a clock for identifying equidistant points in time at which the ADC performs the one or more measurements of the gate voltage during the off phase and during the on phase.

19. The driver circuit of claim 6, wherein the circuit parameter comprises a delay parameter, and the driver circuit is further configured to determine a gate charge parameter based on the delay parameter and a current level used on the multi-function pin.

20. The driver circuit of claim 6, wherein the driver circuit is further configured to determine a capacitance associated with the power switch based on a gate charge and a gate voltage.

21. The driver circuit of claim 6, wherein the driver circuit comprises a digital interface to a processor, and wherein the driver circuit is configured to output one or more online characterization parameters to the processor in response to operating in the online characterization mode.

22. A method of operating a driver circuit for controlling a power switch, the method comprising: Delivering a driving signal from an output pin to the power switch to control the power switch to be turned on; as well as The multi-function pin is controlled via a state machine, wherein the state machine is configured to select between a soft-off mode of the power switch, a clamping mode of the power switch, and an in-circuit characterization mode of the power switch.

23. A system comprising: Power switch; a driver circuit configured to control the power switch based on a drive signal; as well as a processor configured to deliver a control signal to the driver circuit, wherein the control signal defines the drive signal, wherein the driver circuit comprises: an output pin, wherein the driver circuit is configured to transmit the drive signal from the output pin to the power switch to control the turning on of the power switch; Multi-function pins; and A state machine is configured to define operation of the driver circuit using the multi-function pin, wherein the state machine is configured to select between a soft-off mode, a clamping mode, and an in-circuit characterization mode.

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