Controlling power switching elements using sensing switching elements

Abstract

The invention relates to controlling power switching elements using sensing switching elements. A circuit for controlling a power switching element includes: a drive switching element configured to couple a voltage source to a gate of the power switching element using a drive current; and a sensing switching element configured to generate an indication of a voltage drop at the driving switching element based on the reference current. The circuit also includes a drive circuit device configured to generate a drive current including a control current proportional to the reference current and a compensation current based on an indication of a voltage drop at the drive switching element.

Description

Technical Field

[0001] The present disclosure relates to circuits and techniques for controlling power switching elements. Background Art

[0002] The gate driver circuit activates a switching element (e.g., a power transistor) based on a switching signal. For example, the gate driver circuit can drive the switching element to couple a phase of the motor to a high voltage rail (e.g., a battery voltage) during a first portion of the switching signal and to couple the phase of the motor to a low voltage rail (e.g., a reference voltage or a ground voltage) during a second portion of the switching signal.

[0003] Public content

[0004] In general, the present disclosure relates to techniques for reducing variations in current used to drive power switching elements. During the charging and discharging phases, the output current used to control the gate of the power switching element may be affected by a voltage drop (e.g., a drain-source voltage drop) at the driving switching element. The techniques described herein compensate for the output current provided by the control circuit to reduce or eliminate power supply variations. For example, the sensing switching element can be configured to generate an indication of the voltage drop at the driving switching element based on a reference current. In this example, the driving circuit device can generate a driving current that includes both a control current and a compensation current, the control current being proportional to the reference current and the compensation current being based on an indication of the voltage drop at the driving switching element.

[0005] In one example, the present disclosure describes a circuit for controlling a power switching element. The circuit includes a drive switching element configured to couple a voltage source to a gate of the power switching element using a drive current; and a sense switching element configured to generate an indication of a voltage drop across the drive switching element based on a reference current. The circuit also includes a drive circuit device configured to generate the drive current, the drive current including both a control current and a compensation current, the control current being proportional to the reference current, and the compensation current being based on the indication of the voltage drop across the drive switching element.

[0006] In another example, the present disclosure describes a system including a power switching element and a drive switching element configured to couple a voltage source to a gate of the power switching element based on a drive current. The system also includes a sense switching element configured to generate an indication of a voltage drop across the drive switching element based on a reference current, and a drive circuit device configured to generate a drive current including both a control current and a compensation current, the control current being proportional to the reference current and the compensation current being based on the indication of the voltage drop across the drive switching element.

[0007] In one example, the present disclosure describes a method that includes generating an indication of a voltage drop across a drive switching element based on a reference current, and generating a drive current that includes both a control current and a compensation current, the control current being proportional to the reference current and the compensation current being based on the indication of the voltage drop across the drive switching element. The drive switching element is configured to couple a voltage source to a gate of a power switching element based on the drive current.

[0008] The details of these and other examples are set forth in the accompanying drawings and the description that follows.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 illustrating an example system for controlling a power switch element using a sensing switch element, in accordance with one or more techniques of this disclosure.

[0010] Figure 2 is a block diagram illustrating an example system for controlling power switching elements in motor control applications, in accordance with one or more techniques of this disclosure.

[0011] Figure 3 is a conceptual diagram illustrating an example system for controlling a power switching element, according to one or more techniques of this disclosure.

[0012] Figure 4 is a diagram illustrating a method for controlling a Figure 1 A block diagram details a first example of a system of power switching elements.

[0013] Figure 5 is a diagram illustrating one or more techniques according to the present disclosure Figure 4 A circuit diagram of an example detail of the system.

[0014] Figure 6 is a diagram illustrating a method for controlling a Figure 1 A block diagram details a second example of a system of power switching elements.

[0015] Figure 7 is a diagram illustrating one or more techniques according to the present disclosure Figure 6 A circuit diagram of an example detail of the system.

[0016] Figure 8 is a graph illustrating charging current error for various voltages at a 1 mA power supply, in accordance with one or more techniques of this disclosure.

[0017] Figure 9is a graph illustrating charging current error for various voltages at a 150 mA power supply, in accordance with one or more techniques of this disclosure.

[0018] Figure 10 is a graph illustrating charging current versus time at a 1 mA power supply, in accordance with one or more techniques of this disclosure.

[0019] Figure 11 is a graph illustrating charging current versus time at a 150 mA power supply, in accordance with one or more techniques of this disclosure.

[0020] Figure 12 is a flowchart illustrating an example process in accordance with one or more techniques of this disclosure. DETAILED DESCRIPTION

[0021] Figure 1 is a block diagram illustrating an example system 100 for controlling a power switch element 106 using a sense switch element 122, according to one or more techniques of this disclosure. Figure 1 As shown in the example, the system 100 may include a control circuit device 102 , a voltage source 104 , and a power switching element 106 .

[0022] The voltage source 104 can be configured to provide electrical power to one or more other components of the system 100. For example, the voltage source 104 can be configured to supply input power to activate the power switching element 106. In some examples, the voltage source 104 provides a voltage boosted from a battery voltage. In some examples, the voltage source 104 can be a charge pump configured to supply a voltage greater than the battery voltage (V BAT ) of the charge pump voltage (V CP ).

[0023] The power switch element 106 may be configured to generate a conductive channel based on a signal at the gate 107 of the power switch element 106. For example, the power switch element 106 may be configured to generate a conductive channel when a voltage at the gate 107 of the switch element 106 exceeds a threshold.

[0024] Examples of switching elements may include, but are not limited to, silicon-controlled rectifiers (SCRs), field-effect transistors (FETs), and bipolar junction transistors (BJTs). 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, depletion-mode p-channel MOSFETs (PMOS), enhancement-mode PMOS, depletion-mode n-channel MOSFETs (NMOS), enhancement-mode NMOS, double-diffused MOSFETs (DMOS), any other type of MOSFET, or any combination thereof. Examples of BJTs may include, but are not limited to, PNP, NPN, heterojunction, or any other type of BJT, or any combination thereof. The switching element may be a high-side or low-side switching element. For example, the power switching element 106 may include a high-side switching element. Additionally, the switching element may be voltage-controlled and / or current-controlled. Examples of current-controlled switching elements may include, but are not limited to, gallium nitride (GaN) MOSFETs, BJTs, or other current-controlled elements.

[0025] The control circuit device 102 may include a driver circuit device 112 and a driver switching element 120. The control circuit device 102 may include one or more processors, such as one or more microprocessors, digital signal processors (DSPs), application specific integrated circuits (ASICs), field programmable gate arrays (FPGAs), or any other equivalent integrated or discrete logic circuit devices, as well as any combination of these components. The term "processor" or "processing circuit device" may generally refer to any of the above logic circuit devices, alone or in combination with other logic circuit devices, or any other equivalent circuit.

[0026] The driver switching element 120 can be configured to couple the voltage source 104 to the gate 107 of the power switching element 106 using a drive current. As discussed in further detail below, the driver circuit device 112 can provide the drive current to the power switching element 106. For example, the driver circuit device 112 can provide the drive current to the gate 107 of the power switching element 106.

[0027] The driver circuit device 112 may include a sensing switch element 122. The sensing switch element 122 may be configured to generate an indication of a voltage drop at the driver switch element 120 based on a reference current. The driver circuit device 112 may use the indication of the voltage drop as described in further detail below to generate a compensation current (also referred to herein as a "comp. current"). The compensation current may correct for the voltage drop at the driver switch element 120. The driver circuit device 112 may be configured to generate a control current using the reference current. For example, the driver circuit device 112 may generate a drive current that includes a control current that is greater than the reference current by a ratio "K," where "K" is a positive integer greater than 1.

[0028] According to the technology of the present disclosure, the sensing switch element 122 can generate a voltage drop (V DS ). In this example, the driver circuit device 112 can generate a drive current to include both a control current and a compensation current, the control current being proportional to the reference current and the compensation current being based on an indication of a voltage drop across the drive switching element. The drive switching element 120 can be configured to couple the voltage source 104 to the gate 107 of the power switching element 106 based on the drive current. In this manner, the driver circuit device 112 can provide a more constant drive current to the drive switching element 120 than a system that does not include a compensation current, which can help reduce power dissipation in the system 100 and / or reduce the overall amount of radiation emitted by a device using the system 100.

[0029] Figure 2 is a block diagram illustrating an example system 200 for controlling a power switching element 206 in a motor control application, in accordance with one or more techniques of this disclosure. Figure 2 For example purposes only Figure 1 System 200 includes a control circuit device 202 , high-side switching elements 206 - 208 , low-side switching elements 250 - 252 , and a motor 254 . Control circuit device 202 includes a drive circuit device 212 , a drive switching element 220 , and a drive switching element 221 .

[0030] For high voltage gate driver circuits (e.g., used in motor control applications), the output current (e.g., for driving a half-bridge circuit) may vary with the supply voltage during the charging and / or discharging phases due to the voltage drop across the output stage. Figure 2 In the example of FIG, high-side switching elements 206-208 and low-side switching elements 250-252 can form a half-bridge in a motor control application. System 200 can receive a power supply voltage (VBAT), such as, for example, a 12V power supply voltage. The power supply voltage can be provided by, for example, a battery and / or other source.

[0031] exist Figure 2 In the example of , the high-side switch elements 206-208 can be turned on by increasing the gate voltage relative to the source voltage. For example, the high-side switch element 206 can be turned on by increasing the voltage at the gate of the high-side switch element 206 relative to the voltage at the source of the high-side switch element 206. Therefore, some systems can use a floating gate driver to support an increase in voltage relative to the power supply voltage (e.g., VBAT). After the high-side switch element 206 is turned on, the source of the high-side switch element 206 can be approximately equal to the power supply voltage (e.g., SHx~VBAT). The low-side switch elements 250-252 can be turned on by increasing the gate voltage relative to the source voltage. For example, the low-side switch element 250 can be turned on by increasing the voltage at the gate of the low-side switch element 250 relative to the voltage at the source of the low-side switch element 250. A resistor can be placed between the source and ground (GND) on one or more of the low-side switch elements 250-252 for current sensing. As used herein, ground can refer to a reference voltage and / or grounding.

[0032] The gate of the active high-side switching element can be pulled up to above the power supply voltage to fully turn on the active high-side switching element. For example, the switching element 206 can be pulled up to about 10V above the power supply voltage (e.g., to about 22V) to fully turn on the switching element 206. Figure 2 In the example, the voltage at the gate of switching element 206 can be pulled above the power supply voltage (e.g., VBAT) by injecting a controlled current into the gate of switching element 206, for example, using driver switching element 220, which is biased from a boosted power rail (VCP) that supplies a higher voltage than the power supply voltage (e.g., VCP > VBAT). When the charging phase begins, the voltage difference between the boosted power supply and the gate of switching element 206 can be equal to the boosted voltage (e.g., VCP), and during the charging phase, the voltage difference between the boosted power supply and the gate of switching element 206 can drop to several volts. Driver switching element 220 can have a poor output impedance (e.g., the output stage can be constructed with a high-voltage-compatible device with low output resistance). Therefore, voltage variations between before the start of the charging phase and during the charging phase can significantly affect the accuracy and / or performance of control circuit device 202. Furthermore, the inability to precisely control the rate of change of switching element 206 can also lead to radiation issues.

[0033] Figure 3 is a conceptual diagram illustrating an example system 300 for controlling a power switch element 306 according to one or more techniques of this disclosure. Figure 1-2 discuss Figure 3System 300 includes a control circuit device 302, a high-side power switch element 306 (also referred to herein as "power switch element 306"), and a low-side power switch element 350. System 300 may include an intrinsic capacitance 356 (e.g., a gate-source capacitance of power switch element 306) and an intrinsic capacitance 357 (e.g., a gate-source capacitance of low-side power switch element 350).

[0034] The control circuit device 302 can control the active power stage (eg, high-side and / or low-side power switching elements). For example purposes only, Figure 3 The active power stage is discussed with respect to the high-side power switch element, or more specifically, the high-side power switch element 306 (HSx). However, in some examples, the techniques described with respect to the high-side power switch element 306 (HSx) can be applied to other high-side power switch elements and / or low-side power switch elements (e.g., the low-side power switch element 350). The control circuit device 302 includes a reference current generator 310, a current mirror 360 (e.g., a 1:1 current mirror), a pre-driver stage 330, a current mirror 362, a compensation circuit device 341, a high-side driver stage 332 (also referred to herein as "driver stage 341"), and a low-side driver stage 333. The pre-driver stage 330 includes a reference transistor 364, a charging current transistor 366, and a resistive element 368. The driver stage 332 includes a resistive element 374, a driver switch element 320, a resistive element 375, and a driver switch element 321. The compensation circuit device 341 includes a charging current compensation circuit device 342 (which is Figure 4 、 Figure 5 ) and the drive current compensation circuit device 343 (which is discussed in further detail in Figure 6 、 Figure 7 (discussed in further detail in ).

[0035] To fully turn on the power switch element 306, the control circuit device 302 can pull the gate potential (GHx) of the power switch element 306 toward the boost voltage (VCP) by, for example, injecting a controlled current (e.g., Mchg) through the drive switch element 320. The process of turning on the power switch element 306 (e.g., HSx) has a direct impact on several performance parameters (such as, for example, power dissipation and / or electromagnetic radiation), so the current through Mchg can be precisely controlled by the control circuit device 302.

[0036] Reference current generator 310 can feed a reference current (Iref) into reference transistor 364 (e.g., Mref transistor) within pre-driver stage 330 (e.g., VGS_REF block). Reference current generator 310, together with reference transistor 364, can generate a corresponding VGS voltage, which is then converted to Ivgs current via resistive element 368 (e.g., R resistor). Control circuit device 302, including current mirror 362, feeds Ivgs current into resistive element 374 (e.g., a resistor placed on the Mchg gate) within driver stage 332, such that VGS_Mref = VGS_Mchg. Because these two devices (e.g., reference transistor 364 and switch element 320) have a ratio of 1:K (where K is a positive integer), the charging current is proportional to Iref. Consequently, gate control of power switch element 306 can be achieved using a drive current (e.g., driver stage 332) that is proportional to the internal reference current (VGS_REF). This Iref→IVgs→Iref conversion may be used to account for a high range of available charging current values, which may help ensure that both reference transistor 364 and switching element 320 (eg, Mref and Mchg) operate under the same conditions.

[0037] At the beginning of the conduction of the power switch element 306 (e.g., the HSx conduction phase), the drain-source voltage of the driver switch element 320 (e.g., VDS of Mchg) is approximately equal to the boost voltage (e.g., ~VCP), which may result in a charging current error caused by a finite output resistance. The present disclosure proposes two processes for correcting the current error caused by the finite output resistance. The two proposed processes for compensating the driver output current include: (1) sensing the VCP voltage and generating a correction term for the reference current (Iref compensation), which is indicated as the charging current compensation circuit device 342; and (2) sensing the drain-source voltage (VDS) of the driver output stage and generating a correction term for the charging device gate control current (Ivgs compensation), which is indicated as the driving current compensation circuit device 343.

[0038] Some advantages of using these processes (e.g., charge current compensation circuitry 342 and / or drive current compensation circuitry 343) can include one or more of the following: for example, improved drive performance, lower emissions, and the ability to use less expensive technology nodes with poor device performance. For example, during the charge / discharge phase, the output current of the driver (used to control the gate of the active device) is affected by the voltage drop across its output stage. Charge current compensation circuitry 342 and / or drive current compensation circuitry 343 can compensate the output current of the driver so that the output current of the driver is less sensitive to power supply variations, which can help improve rate of change control, potentially resulting in lower emissions and / or better performance. Compared to the case where no compensation is employed, a system using charge current compensation circuitry 342 and / or drive current compensation circuitry 343 can reduce the charge current error from approximately 20% to less than 2% compared to a system omitting both charge current compensation circuitry 342 and drive current compensation circuitry 343.

[0039] Figure 4 is a diagram illustrating a method for controlling a Figure 1 A block diagram of a first example detail of a system of power switching elements. For example purposes only, in conjunction with Figure 1-3 discuss Figure 4 The control circuit arrangement 402 is configured to drive the power switching element 406 . The control circuit arrangement 402 includes a reference current generator 410 and a driver circuit arrangement 412 . The driver circuit arrangement 412 includes a pre-driver stage 430 and a driver stage 432 .

[0040] The driver circuitry 412, or more specifically, the pre-driver stage 430, includes a compensation circuitry 442, which may be Figure 3 An example of a charging current compensation circuit arrangement 342 is shown. Compensation circuit arrangement 442 can be configured to generate a correction current using an indication of a voltage drop generated by sense switching element 422. In this example, charging current generator 440 can be configured to generate the charging current using a corrected reference current that includes a combination of a reference current output by reference current generator 410 and a correction current output by compensation circuit arrangement 442. Driver stage 432 can be configured to generate a drive current based on the charging current output by pre-driver stage 430. Using a corrected reference current to generate the charging current can help reduce variations in the current driving power switching element 406 compared to a system that generates the charging current using only a reference current.

[0041] Figure 5 is a diagram illustrating one or more techniques according to the present disclosure Figure 4 For example purposes only, the circuit diagram of the system is shown in detail. Figure 1-4 discuss Figure 5 The control circuit arrangement 502 includes a reference current generator 510, a current mirror 560 and a pre-driver stage 530. Although not shown, the control circuit arrangement 502 may include a driver stage, such as Figure 3 Driver stage 332. In some examples, control circuitry 502 can include a driver stage for one or more high-side switching elements and / or low-side switching elements.

[0042] The pre-driver stage 530 includes a charging current generator 540 and a compensation circuit device 542. The charging current generator 540 includes a reference transistor 564, a charging current transistor 566, and a resistive element 568. The reference transistor 564 can be configured to generate a reference voltage using a calibrated reference current. For example, the calibrated reference current can be represented by (1-α)*Iref, where α is a correction factor and Iref is a reference current generated by the reference current generator 510. The charging current transistor 566 can be configured to generate a charging current (e.g., Ivgs_chg) using the reference voltage using the resistive element 568.

[0043] exist Figure 5 In the example of FIG, a current mirror 560 (also referred to herein as the “first current mirror 560”) can be configured to output a corrected reference current. A reference transistor 564 includes a gate, a drain, and a source, the drain of which is configured to receive the corrected reference current from the current mirror 560. In this example, the sense switch element 522 includes a gate, a drain, and a source, the gate of which is coupled to the gate of the reference transistor 564, and the source of which is coupled to the source of the reference transistor 564. A current mirror 578 (also referred to herein as the “second current mirror 578”) can be configured to supply a correction current to the drain of the sense switch element 522 and subtract the correction current from the reference current to generate a corrected reference current.

[0044] exist Figure 5In an example, the sensing switch element 522 (e.g., Msns) can be similar to or identical to the reference transistor 564 (e.g., Mref) and biased with the same current and having approximately the same drain-source voltage (VDS) added to sense the boost voltage (e.g., VCP voltage). For example, the switch element 522 and the reference transistor 564 can be formed on the same die. Since the drain current varies with the drain-source voltage, the current through the sensing switch element 522 (e.g., Msns) is higher than the injected current (e.g., Iref). This difference can be fed to the current mirror 578 (e.g., M1-M2 mirror) and acts as a correction current that can be directly subtracted from the injected reference current (e.g., Iref). In this example, the reference transistor 564 (e.g., Mref) can be biased with an adjusted Iref value (e.g., (1-α)*Iref) depending on the boost voltage (e.g., VCP). Thus, driving the drive switch element (e.g., Figure 3 The charging current (eg, Ivgs_chg) of the driving switching element 320 may include a compensation factor (eg, α) that may help make the driving switching element drain current insensitive to variations in the boost voltage (eg, VCP).

[0045] Figure 6 is a diagram illustrating a method for controlling a Figure 1 A block diagram of a second example detail of a system of power switching elements. For example purposes only, in conjunction with Figure 1-5 discuss Figure 6 The control circuit arrangement 602 is configured to drive the power switching element 606 . The control circuit arrangement 602 includes a reference current generator 610 and a driver circuit arrangement 612 . The driver circuit arrangement 612 includes a pre-driver stage 630 and a driver stage 632 .

[0046] The driver circuit device 612, or more specifically, for example, the pre-driver stage 630 includes a charging current generator 640, which is configured to generate a control current based on the reference current output by the reference current generator 610. In this example, the driver stage 632 includes a compensation circuit device 643, which can be Figure 3An example of a drive current compensation circuit device 343 of FIG. The compensation circuit device 643 can be configured to generate a compensation current using an indication of a voltage drop generated by the sensing switch element 622. In this example, the compensation circuit device 643 can be configured to generate a corrected charging current based on the control current and the compensation current. The driver stage 632 can be configured to generate a drive current based on the corrected charging current. For example, the driver stage 632 can be configured to generate a drive current that is proportional to the corrected charging current (e.g., at a ratio of 1:K, where K is a positive integer). Generating a drive current based on the corrected charging current can help reduce variations in the current driving the power switching element 606 compared to a system that generates a charging current using a charging current generated based solely on the control current.

[0047] Figure 7 is a diagram illustrating one or more techniques according to the present disclosure Figure 6 For example purposes only, the circuit diagram of the system is shown in detail. Figure 1-6 discuss Figure 7 The control circuit device 702 is configured to drive a power switching element. The control circuit device 702 includes a reference current generator 710, transistors 780A and 780B forming a current mirror 780, and a driver stage 732. The driver stage 732 includes a compensation circuit device 743, a resistive element 775, and a driver switching element 744. The driver switching element 744 can be configured to generate a drive current based on the corrected charging current output by the compensation circuit device 743.

[0048] The compensation circuit device 743 may include a control current source 783 (also referred to herein as a first control current source 783) configured to output a control current. In this example, the sense transistor 722 (also referred to herein as the first sense transistor 722) includes a gate, a drain, and a source, wherein its gate is coupled to the control current source 783. The compensation circuit device 743 may also include a first resistive element 773 coupled in parallel with the gate of the sense transistor 722 and the source of the sense transistor 722. In this example, the sense transistor 722 may be configured to generate an indication of a voltage drop as a current flowing from the drain of the sense transistor 722 to the source of the sense transistor 722 in response to a voltage caused by the charging current flowing through the first resistive element 773.

[0049] The compensation circuitry 743 may further include a second sense transistor 786, a first current mirror 783, a second resistive element 788, and a third sense transistor 784. The second sense transistor 786 may include a gate, a drain, and a source. The first current mirror 783 may be configured to mirror the error current flowing from the drain of the first sense transistor 722 to the source of the first sense transistor 722 to the drain of the second sense transistor 786. The second resistive element 788 may be coupled in parallel with the gate and source of the second sense transistor 786. The third sense transistor 784 may include a gate, a drain, and a source, wherein its gate is coupled to the drain of the second sense transistor 786 and its source is coupled to the gate of the second sense transistor 786. The third sense transistor 784 may be configured to generate a compensation current at the drain of the third sense transistor 784. The first sense transistor 722 and the second sense transistor 786 may be matched to each other (eg, having a 1:1 ratio), and each matched to drive the switching element 744 (eg, having a 1:1 ratio, where K is a positive integer).

[0050] The compensation circuit device 743 may further include a second control current source 782 configured to output a current proportional to the control current. The current mirror 780 (also referred to herein as the fourth current mirror 780) may be configured to mirror a current proportional to the control current (e.g., 2*Ivgs) minus the compensation current to a corrected charging current (e.g., Ivgs_chg). The driver stage 732 may be configured to generate a drive current proportional to the corrected charging current. For example, the driver stage 732 may be configured to generate a drive current having a ratio of 1:K to the corrected charging current, where K is a positive integer.

[0051] Figure 7 The example circuit uses the principle of supply voltage monitoring, but Figure 6In the example of FIG, sensing is performed directly in the driver stage 732. The sense transistor 722 (e.g., having an aspect ratio of 1:K relative to Mchg and approximately the same VDS as Mchg_sns) can be biased with Ivgs through a second resistive element 788 (e.g., an Rs resistor). At the beginning of the charging phase, the VDS of the sense transistor 722 (e.g., Mchg_sns) can be approximately equal to the boost voltage (e.g., ~VCP). The error current (Ichg_sns) can be mirrored and become the reference current (Mcorr-RS) of another VGS_REF structure. The output of this structure is the VGS_Mcorr / R current and includes the VDS current error of the sense transistor 722, which is then subtracted from the main current 2*IVGS. The drive switch element 744 can be biased with an adjusted Ivgs_chg value depending on its VDS. Therefore, the output current of the drive switch element 744 includes a compensation factor, which can help make the drive switch element 744 insensitive to VDS variations.

[0052] Figure 8 is a graph illustrating the charge current error for various voltages at a 1 mA power supply according to one or more techniques of the present disclosure. Figure 1-7 discuss Figure 8 . Figure 8 A comparison is shown between charging current compensation circuitry 342 (also referred to herein as IVGS compensation), drive current compensation circuitry 343 (also referred to herein as IREF compensation), and no compensation. Figure 8 The horizontal axis represents the boost voltage (VCP) in volts (V), while Figure 8 The vertical axis represents a first charging current error 802 without compensation, a second charging current error 804 with the charging current compensation circuit device 342, and a third charging current error 806 with the driving current compensation circuit device 343. In order to emphasize the performance, the evaluation is performed for two extreme values ​​of the charging current. Figure 8 As shown, for a charging current (Imchg) set to 1 mA, the error rises to ∼25% for high supply voltage without compensation, while the proposed compensation technique reduces the error to below 1.5%.

[0053] Figure 9 is a graph illustrating the charge current error for various voltages at a 150mA power supply according to one or more techniques of the present disclosure. Figure 1-8 discuss Figure 9 . Figure 8 A comparison is shown between the charging current compensation circuitry 342 (also referred to herein as IVGS compensation), the driving current compensation circuitry 343 (also referred to herein as IREF compensation), and no compensation. Figure 9 The horizontal axis represents the boost voltage (VCP) in volts (V), while Figure 9 The vertical axis represents a first charging current error 902 without compensation, a second charging current error 904 with the charging current compensation circuit device 342, and a third charging current error 906 with the driving current compensation circuit device 343. In order to emphasize the performance, the evaluation is performed for two extreme values ​​of the charging current. Figure 9 As shown, the 150mA charging current behavior produces the same Figure 8 Similar results are shown for the 1mA behavior of the CMOS circuit, where the current error is kept below 2% using the proposed compensation technique. Any remaining DC offset can be easily removed by fine-tuning.

[0054] Figure 10 is a graph illustrating the charging current over time at 1 mA power supply according to one or more techniques of the present disclosure. Figure 1-9 discuss Figure 10 . Figure 10 The horizontal axis represents time, Figure 10 The vertical axis represents a first charging current 1002 without compensation, a second charging current 1004 with the charging current compensation circuit device 342, and a third charging current 1006 with the driving current compensation circuit device 343. As shown in the figure, using the charging current compensation circuit device 342 or the driving current compensation circuit device 343, the error of the 1mA charging current is less than 2%.

[0055] Figure 11 is a graph illustrating the charging current versus time at a 150 mA power source according to one or more techniques of the present disclosure. Figure 1-10 discuss Figure 11 . Figure 11 The horizontal axis represents time, and Figure 11 The vertical axis represents a first charging current 1102 without compensation, a second charging current 1104 with the charging current compensation circuit device 342, and a third charging current 1106 with the driving current compensation circuit device 343. As shown in the figure, using the charging current compensation circuit device 342 or the driving current compensation circuit device 343, the error of the 150mA charging current is less than 2%.

[0056] Figure 12 is a flowchart illustrating an example process according to one or more techniques of the present disclosure. Figure 1-11 discuss Figure 12The control circuitry 102 may generate an indication of a voltage drop across the drive switching element based on a reference current (1202). The control circuitry 102 may generate a drive current to include both a control current and a compensation current, the control current being proportional to the reference current and the compensation current being based on the indication of the voltage drop across the drive switching element (1204). The drive switching element 120 may be configured to couple the voltage source 104 to the gate of the power switching element 106 based on the drive current, wherein the drive switching element is configured to couple the voltage source to the gate of the power switching element based on the drive current.

[0057] For example, Figure 4 The compensation circuitry 442 can be configured to generate a correction current using an indication of the voltage drop generated by the sense switching element 422. In this example, the charge current generator 440 can be configured to generate the charge current using a corrected reference current. The corrected reference current can include a combination of the reference current and the correction current. The driver stage 432 can be configured to generate a drive current based on the charge current.

[0058] In some examples, Figure 6 The charging current generator 640 can be configured to generate a control current based on a reference current. In this example, the compensation circuitry 643 can be configured to generate a compensation current using an indication of a voltage drop generated by the sensing switching element, and to generate a corrected charging current based on the control current and the compensation current. The driver stage 632 can be configured to generate a drive current based on the corrected charging current.

[0059] The following clauses may describe one or more aspects of the present disclosure.

[0060] Item 1: A circuit for controlling a power switching element, the circuit comprising: a drive switching element configured to couple a voltage source to a gate of the power switching element using a drive current; a sense switching element configured to generate an indication of a voltage drop at the drive switching element based on a reference current; and a drive circuit device configured to generate the drive current, the drive current comprising both a control current and a compensation current, the control current being proportional to the reference current and the compensation current being based on the indication of the voltage drop at the drive switching element.

[0061] Item 2: The circuit of Item 1, wherein the driving circuit device includes: a compensation circuit device configured to generate a correction current using an indication of a voltage drop generated by a sensing switching element; a charging current generator configured to generate a charging current using a corrected reference current, the corrected reference current comprising a combination of a reference current and a correction current; and a driving stage configured to generate a driving current based on the charging current.

[0062] Clause 3: The circuit of clause 2, wherein the driver stage is configured to generate a drive current proportional to the charge current output by the charge current generator.

[0063] Clause 4: The circuit of clauses 2-3, wherein the charging current generator comprises: a reference transistor configured to generate a reference voltage using the corrected reference current; and a charging current transistor configured to generate the charging current using the reference voltage with a resistive element.

[0064] Item 5: The circuit of Item 4 further includes: a first current mirror configured to output a corrected reference current; wherein the reference transistor includes a gate, a drain, and a source, and its drain is configured to receive the corrected reference current from the first current mirror; wherein the sensing switch element includes a gate, a drain, and a source, its gate is coupled to the gate of the reference transistor, and its source is coupled to the source of the reference transistor; and a second current mirror configured to supply a correction current to the drain of the sensing transistor and subtract the correction current from the reference current to generate a corrected reference current.

[0065] Clause 6: The circuit of clause 1, wherein the drive circuit device includes: a charging current generator configured to generate a control current based on a reference current; a compensation circuit device configured to: generate a compensation current using an indication of a voltage drop generated by the sensing switching element; and generate a corrected charging current based on the control current and the compensation current; and a driver stage configured to generate the drive current based on the corrected charging current.

[0066] Clause 7: The circuit of clause 6, wherein the driver stage is configured to generate a drive current proportional to the corrected charging current.

[0067] Clause 8: The circuit of clauses 6-7, wherein the compensation circuit comprises: a control current source configured to output a control current; a sensing transistor, wherein the sensing transistor comprises a gate, a source, and a drain, the gate of which is coupled to the control current source; a first resistive element coupled in parallel with the gate of the sensing transistor and the source of the sensing transistor; and wherein to generate the indication of the voltage drop, the sensing transistor is configured to generate the indication of the voltage drop as a current flowing from the drain of the sensing transistor to the source of the sensing transistor in response to a voltage generated by the charging current flowing through the first resistive element.

[0068] Item 9: The circuit of Item 8, wherein the sensing transistor includes a first sensing transistor, and wherein the compensation circuit device further includes: a second sensing transistor including a gate, a drain, and a source; a first current mirror configured to mirror an error current flowing from the drain of the first sensing transistor to the source of the first sensing transistor to the drain of the second sensing transistor; a second resistive element coupled in parallel with the gate of the second sensing transistor and the source of the second sensing transistor; a third sensing transistor including a gate, a drain, and a source, the gate of which is coupled to the drain of the second sensing transistor and the source of which is coupled to the gate of the second sensing transistor; and wherein the third sensing transistor is configured to generate a compensation current at the drain of the third sensing transistor.

[0069] Item 10: The circuit of Item 9, wherein the compensation circuit device further includes a second control current source, the second control current source being configured to output a current proportional to the control current; and wherein the circuit further includes a fourth current mirror being configured to mirror a current proportional to the control current minus the compensation current into a corrected charging current.

[0070] Clause 11: The circuit of clause 10, wherein the driver stage is configured to generate a drive current proportional to the corrected charging current.

[0071] Clause 12: The circuit of clauses 1-11, wherein the power switching element comprises a high-side switching element.

[0072] Clause 13: The circuit of clauses 1-12, wherein the power switching element is configured to electrically couple a motor phase of the motor to the voltage source when activated by the drive current.

[0073] Clause 14: The circuit of clauses 1-13, wherein the circuit comprises a floating gate driver.

[0074] Clause 15: The circuit of clauses 1-14, wherein the voltage drop at the drive switching element comprises a drain-source voltage drop of the drive switching element.

[0075] Clause 16: The circuit of clauses 1-15, wherein the sense switch element and the drive switch element comprise an aspect ratio of 1:K, where K is a positive integer greater than 1.

[0076] Clause 17: A system comprising: a power switching element; a drive switching element configured to couple a voltage source to a gate of the power switching element based on a drive current; a sense switching element configured to generate an indication of a voltage drop at the drive switching element based on a reference current; and a drive circuit device configured to generate a drive current comprising both a control current and a compensation current, the control current being proportional to the reference current and the compensation current being based on the indication of the voltage drop at the drive switching element.

[0077] Clause 18: The system of clause 17, further comprising a motor coupled to the source of the power switching element.

[0078] Clause 19: The system of clauses 17-18, wherein the drive circuit device includes: a compensation circuit device configured to generate a correction current using an indication of a voltage drop generated by a sensing switching element; a charging current generator configured to generate a charging current using a corrected reference current, the corrected reference current comprising a combination of a reference current and a correction current; and a drive stage configured to generate a drive current based on the charging current.

[0079] Clause 20: A method comprising: generating an indication of a voltage drop at a drive switching element based on a reference current; and generating a drive current to include both a control current and a compensation current, the control current being proportional to the reference current, the compensation current being based on the indication of the voltage drop at the drive switching element, wherein the drive switching element is configured to couple a voltage source to a gate of the power switching element based on the drive current.

[0080] Various aspects have been described in this disclosure. These and other aspects are within the scope of the following claims.

Claims

1. A circuit for controlling a power switching element, the circuit comprising: a drive switching element configured to couple a voltage source to a gate of the power switching element using a drive current; a sense switching element configured to generate an indication of a voltage drop across the drive switching element based on a reference current; as well as A drive circuit device is configured to generate the drive current, the drive current comprising both a control current and a compensation current, the control current being proportional to the reference current, the compensation current being based on the indication of the voltage drop at the drive switching element.

2. The circuit of claim 1 , wherein the driver circuit device comprises: a compensation circuit device configured to generate a correction current using the indication of the voltage drop generated by the sense switching element; a charging current generator configured to generate a charging current using a corrected reference current, the corrected reference current comprising a combination of the reference current and the correction current; as well as The driving stage is configured to generate the driving current based on the charging current. 3 . The circuit of claim 2 , wherein the driver stage is configured to generate the drive current proportional to the charging current output by the charging current generator.

4. The circuit of claim 2 , wherein the charging current generator comprises: a reference transistor configured to generate a reference voltage using the corrected reference current; as well as A charging current transistor is configured to generate the charging current using the reference voltage with a resistive element.

5. The circuit according to claim 4, further comprising: a first current mirror configured to output the corrected reference current; wherein the reference transistor includes a gate, a drain configured to receive the corrected reference current from the first current mirror, and a source; wherein the sensing switch element includes a gate coupled to the gate of the reference transistor, a drain, and a source coupled to the source of the reference transistor; as well as A second current mirror is configured to supply the correction current to the drain of the sense transistor and subtract the correction current from the reference current to generate the corrected reference current.

6. The circuit of claim 1 , wherein the driver circuit device comprises: a charging current generator configured to generate the control current based on the reference current; A compensation circuit device is configured to: generating the compensation current using the indication of the voltage drop generated by the sense switching element; as well as generating a corrected charging current based on the control current and the compensation current; as well as The driving stage is configured to generate the driving current based on the corrected charging current. 7 . The circuit of claim 6 , wherein the driver stage is configured to generate the drive current proportional to the corrected charging current.

8. The circuit of claim 6 , wherein the compensation circuit comprises: a control current source configured to output the control current; the sense transistor, wherein the sense transistor includes a gate, a drain, and a source coupled to the control current source; a first resistive element coupled in parallel with the gate of the sensing transistor and the source of the sensing transistor; as well as wherein to generate the indication of the voltage drop, the sensing transistor is configured to generate the indication of the voltage drop as a current flowing from the drain to the source of the sensing transistor in response to a voltage caused by the charging current flowing through the first resistive element.

9. The circuit of claim 8 , wherein the sense transistor comprises a first sense transistor, and wherein the compensation circuit device further comprises: a second sensing transistor comprising a gate, a drain, and a source; a first current mirror configured to mirror an error current flowing from the drain of the first sensing transistor to the source of the first sensing transistor into the drain of the second sensing transistor; a second resistive element coupled in parallel with the gate of the second sensing transistor and the source of the second sensing transistor; a third sensing transistor including a gate coupled to the drain of the second sensing transistor, a drain, and a source coupled to the gate of the second sensing transistor; as well as The third sensing transistor is configured to generate the compensation current at the drain of the third sensing transistor.

10. The circuit according to claim 9, wherein the compensation circuit device further comprises a second control current source configured to output a current proportional to the control current; and The circuit further includes a fourth current mirror configured to mirror the current proportional to the control current minus the compensation current into the corrected charging current. 11 . The circuit of claim 10 , wherein the driver stage is configured to generate the drive current proportional to the corrected charging current.

12. The circuit of claim 1, wherein the power switch element comprises a high-side switch element.

13. The circuit of claim 1, wherein the power switching element is configured to electrically couple a motor phase of a motor to the voltage source when activated by the drive current.

14. The circuit of claim 1, wherein the circuit comprises a floating gate driver.

15. The circuit of claim 1, wherein the voltage drop at the drive switching element comprises a drain-source voltage drop of the drive switching element. 16 . The circuit of claim 1 , wherein the sense switch element and the drive switch element comprise an aspect ratio of 1:K, where K is a positive integer greater than 1.

17. A system comprising: Power switching components; a drive switching element configured to couple a voltage source to a gate of the power switching element based on a drive current; a sense switching element configured to generate an indication of a voltage drop across the drive switching element based on a reference current; as well as A drive circuit device is configured to generate the drive current, the drive current comprising both a control current and a compensation current, the control current being proportional to the reference current, the compensation current being based on the indication of the voltage drop at the drive switching element.

18. The system of claim 17, further comprising a motor coupled to the source of the power switching element.

19. The system of claim 17, wherein the driver circuit device comprises: a compensation circuit device configured to generate a correction current using the indication of the voltage drop generated by the sense switching element; a charging current generator configured to generate a charging current using a corrected reference current, the corrected reference current comprising a combination of the reference current and the correction current; as well as The driving stage is configured to generate the driving current based on the charging current.

20. A method comprising: generating an indication of a voltage drop across the driven switching element based on the reference current; as well as generating a drive current to include both a control current and a compensation current, the control current being proportional to the reference current, the compensation current being based on the indication of the voltage drop at the drive switching element, The driving switch element is configured to couple a voltage source to a gate of the power switching element based on the driving current.

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