Regulator circuit, corresponding system and method

Abstract

Embodiments of the present disclosure relate to regulator circuits, corresponding systems, and methods. A circuit includes an electronic switch configured to be coupled between a high voltage node and a low voltage circuit device and configured to couple the low voltage circuit device to the high voltage node. A voltage sense node is configured to be coupled to the high voltage node via a pull-up resistor. Another electronic switch can be switched to an on state to couple the voltage sense node and a control node of the electronic switch. A comparator compares a threshold to a voltage at the voltage sense node and turns on the other electronic switch in response to the voltage at the voltage sense node reaching the threshold. A charge pump coupled to a current flow path of the electronic switch is activated to an on state to pump charge from the current flow path of the electronic switch to the control node of the electronic switch via the other electronic switch switched to the on state.

Description

Technical Field

[0001] This manual relates to regulator circuits.

[0002] One or more embodiments can be applied to drive bypass field-effect transistors in high-voltage start-up regulators used in various products.

[0003] These products can include, for example, chargers / adapters, household appliances such as refrigerators or TVs, industrial machinery, telecommunications equipment, etc. Background Technology

[0004] Regulator circuitry such as a high-voltage start-up (HVS) regulator may include a bypass transistor (e.g., a MOSFET transistor), a pull-up resistor for biasing the gate of the bypass transistor, and a voltage clamp connected between the gate of the bypass transistor and ground to limit the gate voltage range and define the maximum supply voltage output.

[0005] This approach may exhibit certain limitations in terms of power consumption, application input range, and cost.

[0006] For example, in low-power applications, a constraint can be imposed on the minimum (minimum) resistance value of the pull-up resistor.

[0007] In these cases, the trade-off between achieving the minimum resistance value of the pull-up resistor and the lowest (minimum) high voltage input may become critical, while on the other hand, bypass components with gate bias current still represent an attractive and cost-effective solution. Summary of the Invention

[0008] One or more embodiments of this disclosure help to solve the aforementioned problems.

[0009] According to one or more embodiments, such technical features or benefits can be achieved by circuitry as will be described in further detail herein.

[0010] One or more embodiments may relate to a corresponding system. A switch-mode power supply (SMPS) system may be an example of such a system.

[0011] One or more embodiments may involve corresponding methods.

[0012] One or more embodiments can provide a cost-effective solution, primarily compared to using a dedicated HV-MOS with no gate leakage.

[0013] One or more embodiments may use a charge pump to sustain the gate leakage current. Such a charge pump may be provided by the source of a transistor, and its activation may involve pulling up the gate of the bypass transistor.

[0014] In one or more embodiments, the (electronic) switch may be inserted between the gate and the pull-up resistor.

[0015] In response to the input voltage reaching (i.e. rising to) the comparator threshold, the latched comparator can close the switch (i.e. turn it on).

[0016] The charge stored in the capacitor between the pull-up resistor (RHV) and ground helps to pull the gate up before the charge pump is turned on, and it has the ability to provide the supply energy consumed by the comparator / latch and support gate leakage.

[0017] One or more embodiments can effectively address certain limitations in terms of power consumption, application input range, and cost.

[0018] When the high-voltage start-up regulator is activated, the possible presence of the embedded charge pump may result in a negative current being detected on the high-voltage pin.

[0019] In at least one embodiment, a circuit is provided including a first electronic switch having a current flow path through the first electronic switch. The first electronic switch is configured to couple between a high-voltage node and a low-voltage circuit device. The first electronic switch has a control node configured to switch the first electronic switch to an ON state, wherein the first electronic switch electrically couples the low-voltage circuit device to the high-voltage node. A voltage sensing node is configured to be coupled to the high-voltage node via a pull-up resistor. A second electronic switch is coupled between the voltage sensing node and the control node of the first electronic switch. The second electronic switch is switchable to an ON state, wherein the second electronic switch electrically couples the voltage sensing node to the control node of the first electronic switch in response to receiving an ON signal. A comparator is coupled to the voltage sensing node and a threshold. The comparator is configured to compare a voltage at the voltage sensing node with the threshold and generate an ON signal in response to the voltage at the voltage sensing node reaching the threshold. A charge pump is coupled to the current flow path of the first electronic switch and configured to be activated by the second electronic switch switched to the ON state to pump charge from the current flow path of the first electronic switch to the control node of the first electronic switch via the second electronic switch switched to the ON state.

[0020] In at least one embodiment, a power supply system is provided, including a high-voltage source, a low-voltage circuit device, and a circuit. The circuit includes a high-voltage node coupled to the high-voltage source. A first electronic switch has a current flow path through the first electronic switch and is coupled between the high-voltage node and the low-voltage circuit device. The first electronic switch has a control node configured to switch the first electronic switch to an ON state, wherein the first electronic switch electrically couples the low-voltage circuit device to the high-voltage node. A pull-up resistor is coupled between a voltage sensing node and the high-voltage node. A second electronic switch is coupled between the voltage sensing node and the control node of the first electronic switch, and the second electronic switch is switchable to an ON state, wherein the second electronic switch electrically couples the voltage sensing node to the control node of the first electronic switch in response to receiving an ON signal. A comparator is coupled to the voltage sensing node and a threshold, and the comparator is configured to compare the voltage at the voltage sensing node with the threshold and generate an ON signal in response to the voltage at the voltage sensing node reaching the threshold. A charge pump is coupled to the current flow path of the first electronic switch and is configured to be activated by a second electronic switch switched to the on state to pump charge from the current flow path of the first electronic switch to the control node of the first electronic switch via the second electronic switch switched to the on state.

[0021] In at least one embodiment, a method is provided, the method comprising: coupling a first electronic switch between a high-voltage source and a low-voltage circuit device, the first electronic switch having a current flow path through the first electronic switch and a control node; electrically coupling the low-voltage circuit device to the high-voltage source by switching the first electronic switch to an on state via the control node; coupling a voltage sensing node to the high-voltage source via a pull-up resistor; coupling a second electronic switch between the voltage sensing node and the control node of the first electronic switch; coupling the voltage sensing node to the control node of the first electronic switch by switching the second electronic switch to an on state in response to a voltage at the voltage sensing node reaching a threshold; coupling a charge pump to the current flow path of the first electronic switch; and activating the charge pump with the second electronic switch switched to the on state to pump charge from the current flow path of the first electronic switch to the control node of the first electronic switch via the second electronic switch switched to the on state. Attached Figure Description

[0022] One or more embodiments will now be described by way of example only with reference to the accompanying drawings, in which:

[0023] Figure 1 This is an exemplary block diagram of a high-voltage start-up (HVS) regulator;

[0024] Figure 2 This is a block diagram of a high-voltage start-up (HVS) regulator according to one or more embodiments of the present disclosure;

[0025] Figure 3A and Figure 3B It is shown as follows Figure 2 The diagram shows the operation of the regulator;

[0026] Figure 4 This is a transistor-level representation of one or more embodiments of this disclosure;

[0027] Figure 5 This illustrates one or more embodiments. Figure 4 The circuit diagram shown illustrates the implementation of the component (charge pump).

[0028] Figure 6 It is a set of time diagrams illustrating the temporal behavior of a specific signal that may occur in a regulator according to one or more embodiments; and

[0029] Figure 7 This is a circuit diagram illustrating the use of a regulator according to one or more embodiments within the framework of a switch-mode power supply system. Detailed Implementation

[0030] In the following description, one or more specific details are shown to provide a thorough understanding of examples of embodiments described herein. Embodiments may be obtained without one or more specific details, or by utilizing other methods, components, materials, etc. In other instances, known structures, materials, or operations have not been shown or described in detail so as not to obscure certain aspects of the embodiments.

[0031] References to "an embodiment" or "an embodiment" within the framework of this specification are intended to indicate that a particular configuration, structure, or feature described with respect to that embodiment is included in at least one embodiment. Therefore, phrases such as "in an embodiment" or "in one embodiment" that may appear at one or more points in this specification do not necessarily refer to the same embodiment.

[0032] Furthermore, in one or more embodiments, specific conformations, structures, or features can be combined in any suitable manner.

[0033] The headings / references used herein are provided for convenience only and are not intended to limit the scope of protection or the scope of the embodiments.

[0034] Through the detailed description of the present invention, one can refer to... Figure 1 , Figure 1 The circuit diagram of a conventional high-voltage start (HVS) regulator, generally represented by 10, is reproduced.

[0035] This regulator is designed to supply low-voltage power from the high-voltage source VHVIN to the low-voltage section LV. Note that in various types of high-voltage power converters, such a high-voltage start-up regulator may only be used during the power-on phase, after which it can be replaced by a more efficient power supply.

[0036] like Figure 1 The high-voltage start-up regulator 10 shown includes a "bypass" electronic switch MBP (e.g., a MOSFET transistor) that is capable of withstanding the high voltage applied to it.

[0037] In this regard, those skilled in the art will understand that the MOSFET transistor referred to herein as a switch MBP is merely an example: other types of electronic switches (e.g., JFET, BJT, GaN) can be used as switch MBPs.

[0038] like Figure 1 As shown, the switch MBP is arranged such that the current path (source-drain in the case of a field-effect transistor such as a MOSFET) is coupled between the input node, where a high voltage VHVIN can be applied, and the low voltage portion LV, which can be assumed to be ground GND.

[0039] like Figure 1 As shown, the drain D of the MOSFET transistor MBP is connected to the high-voltage input node at VHVIN, while the source S of the MOSFET transistor MBP supplies power to the low-voltage circuit device LV.

[0040] The pull-up resistor RHV is used to bias the control node G (gate) of the bypass switch MBP, in the case of a field-effect transistor such as a MOSFET.

[0041] As shown in the figure, the pull-up resistor RHV is placed between the high-voltage input node at VHVIN and the gate G of the MBP.

[0042] A voltage clamp DZ (e.g., a Zener diode) is positioned between the gate G of the MBP and ground GND to limit the gate voltage range of the MBP and to limit the maximum (maximum) supply voltage for the low-voltage portion LV.

[0043] To achieve this voltage value, the input voltage is selected to be higher than the DZ voltage clamp.

[0044] In low-power applications, a minimum resistance value for RHV is set to limit power waste. Another specification is the minimum (minimum) input voltage (VHVIN) that the high-voltage regulator is expected to supply to downstream circuits. MIN ).

[0045] Assuming the MBP has a gate bias current (I0) GATEFor components, there may be a certain voltage drop on RHV, which establishes a wise trade-off between the constraint of minimum RHV and minimum high voltage input.

[0046] Problems arise when such a compromise cannot be satisfactorily achieved.

[0047] For example, RHV = 10MΩ, I GATE When the current is 10μA, the minimum input voltage is higher than 100V.

[0048] In principle, a lower resistor value can be considered for RHV to distribute the resistance more evenly. It should also be noted that the minimum value of this resistor is related to the desired reduction in standby power consumption, which introduces design constraints.

[0049] Furthermore, using components with leakage in a monolithic or system-in-package (SiP) arrangement can be an attractive option: for example, a high-voltage component with non-zero gate current can represent the only component available in a particular technology process and / or can represent a favorable option considering specific design characteristics.

[0050] For example, gallium nitride (GaN) technology can be chosen for the main switch in a converter due to its improved static and dynamic performance compared to silicon-based power MOS transistors. Adding dedicated components (SIPs with dedicated dies and / or processes) can be more expensive and complex.

[0051] Using a gate bias current I GATE The bypass component MBP can provide a cost-effective and attractive solution (e.g., producing a monolithic solution with only one usable component), the gate bias current I GATE It is forced to flow through the RHV and then into the gate of the MBP. This method may also exhibit various disadvantages: for example, it may be almost unsuitable for very low standby applications and / or may be rendered obsolete due to providing an undesirable, expensive, and complex solution.

[0052] One or more embodiments may be adopted Figure 2 The method shown is used to solve these problems.

[0053] In this respect, it should be understood that:

[0054] Unless the context otherwise requires, the same parts or elements are denoted by the same reference numerals in all the figures, and for the sake of brevity, detailed descriptions will not be repeated in each figure; therefore, they have been combined Figure 1 The parts or elements under discussion are indicated by the same reference numerals throughout the drawings and will not be discussed further.

[0055] For simplicity and ease of understanding, the same notation can be used here to represent nodes or lines in a circuit and the signals (e.g., voltage, current) that appear at those nodes or lines. See, for example, VHVIN as previously introduced;

[0056] The various components shown and discussed for ease of illustration (e.g., the source of the high-voltage VHVIN and the low-voltage circuit device LV) may be elements different from those in the embodiments.

[0057] In such Figure 2 In one or more embodiments shown, a circuit device generally designated as 100 is connected in the middle:

[0058] At a node HV between the resistor RHV and the voltage clamp DZ, and

[0059] The control node G (here, the gate) for switching the MBP.

[0060] As shown in the figure, the circuit device 100 includes an electronic switch SW1 (e.g., a MOSFET transistor) having a current path through it (source-drain in the case of a MOSFET field-effect transistor), the electronic switch SW1 being configured to connect the control node G of the "master" switch MBP to node HV in response to the switch SW1 being "on" (i.e., conducting), and thus to the pull-up resistor RHV.

[0061] As shown in the figure, circuit 100 also includes:

[0062] The capacitor CHV is inserted between node HV and ground (i.e., in parallel with voltage clamp DZ).

[0063] Comparator 102 is configured to sense the voltage at node HV (i.e., the voltage across capacitor CHV) using a threshold VTH (generated in a manner known to those skilled in the art).

[0064] Latch circuit 104 is configured to latch the output of latch comparator 102 and control the state of switch SW1 via its output; and

[0065] The charge pump 106 is inserted between node S (e.g., the source in the case of a field-effect transistor such as a MOSFET) and node HV, which is between the switch MBP and the low-voltage section LV. The charge pump 106 has the purpose of maintaining the bias current through the switch MBP while avoiding an unwanted voltage drop on RHV.

[0066] Figure 3A and Figure 3B Is it like this? Figure 2 Examples of possible operations of the regulator 10 shown.

[0067] Similarly, unless the context otherwise indicates, combinations have been made. Figure 1 and Figure 2 The part or element under discussion Figure 3A and Figure 3B The same reference numerals are used in the accompanying drawings, and for the sake of brevity, they will not be described again.

[0068] More specifically, Figure 3A and Figure 3B It is based on Figure 2 Examples of possible currents in the regulator 10 of the example embodiment:

[0069] Before turning on charge pump 106 ( Figure 3A ),

[0070] After charge pump 106 is turned on ( Figure 3B ).

[0071] When power is applied, assume SW1 is open (not conducting) and there is no current I. GATE It can flow through RHV to node G, and the voltage at node HV follows VHVIN.

[0072] In response to the voltage at node HV reaching the threshold VTH (for example, 20V) of comparator 102, the relevant information is stored by latch 104 and SW1 is closed (i.e. turned on) via the asserted signal SW1_ON.

[0073] During this phase, the charging of capacitor CHV is used to pull up the gate G of the switching MBP (e.g., utilizing the inherent gate-source capacitance) and provides current I to node G. GATE .

[0074] When the voltage across the source S of the MBP is sufficient (i.e., it exceeds the required lower threshold), the charge pump 106 begins to supply current to node HV, drawing current from the source S of the MBP (see...). Figure 3B ).

[0075] Therefore, charge pump 106 provides current I GATE and the current I used to charge the capacitor CHV to a voltage clamping value exceeding HV. GATE The current.

[0076] That is, during high-voltage regulator operation, resistor RHV supplies current I. GATE There is no significant contribution, and the voltage drop across RHV does not limit the minimum input voltage, which is independent of the resistance value of RHV and the strength of IGATE.

[0077] Figure 4 It is based on the latch current comparator 1024. Figure 2 An exemplary transistor-level diagram of a possible embodiment of the layout described herein, wherein the latching current comparator 1024 is configured to facilitate the current IHVtrig through resistor RHV, such that IHVtrig << <IGATE。

[0078] Similarly, unless the context otherwise indicates, combinations have been made. Figure 1 , Figure 2 as well as Figure 3A and Figure 3B The part or element under discussion Figure 4 The same reference numerals are used in the accompanying drawings, and for the sake of brevity, they will not be described again.

[0079] Essentially, the latch comparator 1024 is based on a current mirror M3, which includes two transistors Q1 (arranged as diodes) and Q2. Transistors Q1 and Q2 have current paths (emitter-collector, in the case of bipolar transistors as illustrated herein) running through them, and the current paths define corresponding current flow lines:

[0080] Between node HV and ground GND, via current clamp DZ (transistor Q1), and

[0081] Between the control node (gate) of switch SW1 and ground GND (transistor Q2).

[0082] The interconnected bases of transistors Q1 and Q2 are coupled to node HV via a current flow path (source-drain in the case of a MOSFET transistor as illustrated herein) through another electronic switch M1. The control node of this other electronic switch M1 (gate in the case of a MOSFET transistor as illustrated herein) is coupled to the control node of switch SW1 via a line that applies a switching signal SW1_ON, wherein the parallel connection of another voltage clamp DZUP and another pull-up resistor Rup couples this line to the line / node HV.

[0083] exist Figure 4 In the diagram, the main current before startup is represented by a continuous line. The dashed line represents the main current during startup, while the dotted-dash line represents the main current in a stable state after the charge pump 106 is activated.

[0084] The charge pump 106 can be of any conventional type, such as Dickson, etc. Figure 5 exemplified in .

[0085] Figure 6 Includes a setup time graph of exemplary possible temporal behaviors, which is mapped relative to a common time (horizontal axis) scale for the following signals:

[0086] "High" voltage VHVIN (continuous line)

[0087] Signal SW1_ON (dashed line)

[0088] Voltage at node HV (link)

[0089] The voltage at node G (a mixture of dashed lines and cross lines – + – +, which is ultimately superimposed on the voltage at node HV)

[0090] Voltage S (mixed dashed lines and double cross lines --++--++--).

[0091] Figure 6 The diagram is an example of possible initiation sequences, including events represented by numbers from 1 to 5, for example:

[0092] 1 - Node HV reaches the threshold VTH that triggers SW1 closure (at time tstart);

[0093] 2 - The intrinsic capacitance at node G is charged via charge sharing with capacitor CHV;

[0094] 3 - Charge sharing causes a voltage drop on node HV until the voltage at that node equals the voltage at node G (at time tcharge after tstart);

[0095] The 4-S node follows the node G, the voltage drop between them approaches the threshold of the MBP, and the MBP begins to power the charge pump 106 (time tstartCHP).

[0096] 5 - Charge pump 106 recharges capacitor CHV to voltage clamp.

[0097] Figure 7 This is an exemplary circuit diagram of the possible use of the aforementioned circuit 10 within the framework of a switch-mode power supply (i.e., an electronic power supply system that incorporates a switching regulator to efficiently convert power).

[0098] Similarly, unless the context otherwise requires, parts or elements already discussed in conjunction with the preceding figures... Figure 7 The same reference numerals are used in the accompanying drawings, and for the sake of brevity, they will not be described again.

[0099] Figure 7 Possible uses of embodiments related to a system-in-package (SIP) switch-level package (SIP) switch-mode power controller are illustrated.

[0100] Figure 7This illustrates a possible use of an embodiment in which the main power switch PM (e.g., a power MOSFET transistor) is integrated with a portion of circuitry 10 included in the controller (e.g., clamping circuitry DZ, bypass FET driver 100, and switch MBP) in a switching power controller (with a flyback topology in the purely exemplary case shown), while other components (e.g., resistors RHV) may be external components different from circuitry 100 (and 10).

[0101] For example, this could be the case of a high-voltage source VHVIN, in Figure 7 The term is represented by a bridge rectifier BR, which is powered by an AC source ACin (e.g., the main distribution network) and has an associated smoothing capacitor Cin, which is designed to couple with the line or node VHVIN.

[0102] exist Figure 7 In the configuration shown, instead of being directly coupled to VHVIN as described above, the switch MBP is indirectly coupled to VHVIN (at its drain), i.e., via the primary winding of the converter transformer T.

[0103] exist Figure 7 In the arrangement shown, the low-voltage circuit device LV coupled to the switch MBP (here at the source) includes the power supply section of the SMPS controller, including the power node VDD.

[0104] The external network coupled to node VDD is illustrated as the windings driving the rectifier diodes and the smoothing capacitor Cvdd (not to be confused with the capacitor CHV discussed earlier), which provides an effective auxiliary power supply during regulation. The current generator Icharge is shown as an example of node VDD being charged with a controlled current. The current generator can be replaced by a diode, which is an example of the auxiliary power supply and the power supply from the HVS circuit being decoupled from each other.

[0105] Figure 7 The symbol PM in the designation represents the main switch of the switching converter. Advantageously, this can be the same type of switch, MBP (e.g., a GAN transistor).

[0106] Figure 7 Reference numeral 108 in the figure indicates the logic control circuit device of switch PM, which applies a PWM modulated control signal to the switch via driver 110.

[0107] This can occur in any conventional manner known to those skilled in the art. It should also be understood that... Figure 7 A fairly general representation of the switch controller is provided: therefore, refer to Figure 7 The SMPS converter controller described herein is merely exemplary and not a limitation thereof.

[0108] One or more embodiments can actually be applied to flyback, boost topologies and other types of bypass regulators as high-voltage start-up current generators.

[0109] One or more embodiments can provide various advantages, such as:

[0110] Reduce power consumption

[0111] Remove the restrictions on the application's input range.

[0112] It provides a cost-effective solution compared to using a dedicated HV-MOS that has no gate leakage.

[0113] The gate leakage current flowing in resistor RHV when energized is prevented by switch SW1.

[0114] The comparator and latch circuitry (i.e., 102, 104, 1024) exhibit low power consumption before switch SW1 is turned on.

[0115] A simple charge pump circuit is used to maintain bypass FET gate leakage.

[0116] In short, one or more embodiments eliminate the limitations of conventional high-voltage start-up regulators that use electronic switches with (high) bias current as bypass components.

[0117] In this regard, it should be noted again that although MOSFET transistors are referred to throughout as examples of switching MBPs, other types of electronic switches (e.g., JFETs, BJTs, GaN) can be used for the same purpose.

[0118] This limitation relates to the voltage drop across a pull-up resistor (e.g., RHV), one end of which is used to bias the bypass switch gate, and the other end of which is connected to the main input voltage.

[0119] One or more embodiments use a charge pump to maintain gate leakage current.

[0120] This charge pump can be provided by the source of a transistor, and its activation involves pulling up the gate of the bypass switch MBP.

[0121] In one or more embodiments, the electronic switch SW1 is inserted between the control node (e.g., the gate) of the bypass switch MBP gate and the pull-up resistor. Once the input voltage reaches the comparator threshold, the switch closes (e.g., via a latched comparator).

[0122] By utilizing the ability to supply (and maintain) both the consumption of the comparator / latch and gate leakage before the charge pump is turned on, the charge stored in a capacitor (e.g., CHV) connected between RHV and GND promotes gate pull-up.

[0123] In short, a circuit as illustrated herein (e.g., 10) may include:

[0124] An electronic switch (e.g., MBP) having a current path (e.g., S, D) flowing therethrough, the electronic switch being configured to couple between a high-voltage node (e.g., VHVIN) and a low-voltage circuit device (e.g., LV), the electronic switch having a control node (e.g., G) configured to switch the electronic switch to an ON state, wherein the low-voltage circuit device is coupled to the high-voltage node.

[0125] The circuit illustrated herein may further include a voltage sensing node (e.g., HV) configured to be coupled to a high-voltage node via a pull-up resistor (e.g., RHV).

[0126] Another electronic switch (e.g., SW1) located between the voltage sensing node and the control node of the electronic switch can switch to an ON state in response to an asserted ON signal (e.g., SW1_ON) to couple the voltage sensing node and the control node of the electronic switch.

[0127] A comparator (e.g., 102), coupled to the voltage sensing node and a threshold, is configured to compare the voltage at the voltage sensing node with the threshold, and to assert the turn-on signal in response to the voltage at the voltage sensing node reaching the threshold.

[0128] A charge pump (e.g., 106), coupled to the current flow path of the electronic switch, and configured to be activated by another electronic switch switched to the on state, to transfer charge (e.g., I) via the other electronic switch switched to the on state. GATE The current is pumped from the current flow path of the electronic switch to the control node of the electronic switch.

[0129] The circuits illustrated in this article may include a charging capacitor (e.g., CHV) coupled (e.g., via HV) to a charge pump to be charged, thereby being charged via a charge exceeding the charge pumped to the control node of the electronic switch.

[0130] In the circuit illustrated herein, a charge pump is coupled to a voltage sensing node and configured to pump charge from a current flow path originating from an electronic switch.

[0131] One example circuit described herein may include a latching circuit (e.g., 104) located between a comparator and another electronic switch to latch the turn-on signal therein in response to the voltage at the voltage sensing node reaching the threshold.

[0132] In the circuit illustrated herein, the voltage sensing node is configured as a high-voltage node coupled between the pull-up resistor (e.g., RHV) and a voltage clamp (e.g., DZ) at a reference ground (e.g., GND), the voltage clamp being configured to clamp the voltage at the voltage sensing node to a limit.

[0133] In the circuit illustrated herein, an electronic switch (e.g., MBP) has a first node (e.g., D) configured to couple to a high-voltage node (e.g., VHVIN) and a second node (e.g., S) configured to couple to a low-voltage circuit device (e.g., LV), wherein a charge pump is coupled to the current flow path of the electronic switch at the second node (e.g., S).

[0134] In the circuit illustrated herein, electronic switches and other electronic switches may include field-effect transistors, and optionally MOSFET transistors.

[0135] The power system illustrated here may include:

[0136] High voltage source (e.g., BR, Cin),

[0137] The circuit illustrated herein (e.g., 10) has the high-voltage node (e.g., VHVIN) coupled to a high-voltage source (e.g., BR, Cin), and

[0138] A low-voltage circuit device (e.g., LV) is coupled (e.g., at S) to an electronic switch, wherein the low-voltage circuit device is coupled to a high-voltage node in response to the electronic switch switching to the on state.

[0139] The methods illustrated herein may include supplying low-voltage circuitry (e.g., LV) from a high-voltage source (e.g., BR, Cin) in the following manner:

[0140] An electronic switch (e.g., MBP) is coupled between the high-voltage source and the low-voltage circuit device. The electronic switch has a current flow path (e.g., S, D) and a control node (e.g., G) through it.

[0141] The electronic switch is switched to the ON state via the control node of the electronic switch to couple the low-voltage circuit device to the high-voltage source.

[0142] The voltage sensing node is coupled to the high-voltage source via a pull-up resistor (e.g., RHV).

[0143] Another electronic switch (e.g., SW1) is provided between the voltage sensing node and the control node of the electronic switch.

[0144] A control node that switches another electronic switch (e.g., SW1_ON) to the ON state in response to the voltage at the voltage sensing node reaching a threshold (e.g., VTH) to couple the voltage sensing node and the electronic switch.

[0145] A charge pump (e.g., 106) provides a current flow path coupled to the electronic switch, and

[0146] The charge pump is activated by switching another electronic switch to the on state, so that the charge (e.g., I) is transferred via another electronic switch (SW1) switched to the on state. GATE The current is pumped from the current flow path of the electronic switch to the control node of the electronic switch.

[0147] Without departing from the basic principles, details and embodiments may be changed, even significantly changed, relative to what has been described by example only, without departing from the scope of protection.

[0148] A circuit (10) can be summarized as including: an electronic switch (MBP) having a current flow path (S, D) through the electronic switch, the electronic switch (MBP) being configured to couple between a high-voltage node (VHVIN) and a low-voltage circuit device (LV), the electronic switch (MBP) having a control node (G) configured to switch the electronic switch (MBP) to an ON state, wherein the low-voltage circuit device (LV) is coupled to the high-voltage node (VHVIN), a voltage sensing node (HV) being configured to couple to the high-voltage node (VHVIN) via a pull-up resistor (RHV), and another electronic switch (SW1) located between the voltage sensing node (HV) and the control node (G) of the electronic switch (MBP), the other electronic switch (SW1) being switchable to an ON state to couple the voltage sensing node in response to an asserted ON signal (SW1_ON). The control node (G) of the electronic switch (MBP) includes a comparator (102) coupled to the voltage sensing node (HV) and a threshold (VTH), the comparator (102) being configured to compare the voltage at the voltage sensing node (HV) with the threshold (VTH) and, in response to the voltage at the voltage sensing node (HV) reaching the threshold (VTH), cause (104) to assert the on signal (SW1_ON), ​​and a charge pump (106) coupled to the current flow path of the electronic switch (MBP) and configured to be activated by the other electronic switch (SW1) switched to the on state to pump charge (IGATE) from the current flow path of the electronic switch (MBP) to the control node (G) of the electronic switch (MBP) via the other electronic switch (SW1) switched to the on state.

[0149] Circuit (10) may include a charging capacitor (CHV) coupled (HV) to a charge pump (106) to pump charge (I) to the control node (G) of the switch (MBP). GATE (to charge with excess charge).

[0150] The charge pump (106) can be coupled to the voltage sensing node (HV) and configured to pump charge from the current flow path originating from the electronic switch (MBP).

[0151] The circuit (10) may include a latching circuit (104) between the comparator (102) and another electronic switch (SW1) to latch the turn-on signal (SW1_ON) therein in response to the voltage at the voltage sensing node (HV) reaching the threshold (VTH).

[0152] A voltage sensing node (HV) can be configured to couple to a high-voltage node (VHVIN) between the pull-up resistor (RHV) and a voltage clamp (DZ) at a reference ground (GND), the voltage clamp (DZ) being configured to clamp the voltage at the voltage sensing node (HV) to a limit. An electronic switch (MBP) can have a first node (D) configured to couple to the high-voltage node (VHVIN) and a second node (S) configured to couple to a low-voltage circuit device (LV), wherein a charge pump (106) can be coupled to the current flow path of the electronic switch (MBP) at the second node (S). The electronic switch (MBP) and another electronic switch (SW1) can include field-effect transistors, preferably MOSFET transistors.

[0153] A power supply system can be summarized as including: a high-voltage source (BR, Cin), the circuit (10) described above, the circuit having the high-voltage node (VHVIN) coupled to the high-voltage source (BR, Cin), and a low-voltage circuit device (LV) coupled (S) to the electronic switch (MBP), wherein the low-voltage circuit device (LV) can be coupled to the high-voltage node (VHVIN) in response to the electronic switch (MBP) being switched to an on state.

[0154] A method for supplying a low-voltage circuit device (LV) from a high-voltage source (BR, Cin) can be summarized as follows: coupling an electronic switch (MBP) between the high-voltage source (VHVIN; BR, Cin) and the low-voltage circuit device (LV), the MBP having a current flow path (S, D) through it and a control node (G); switching the electronic switch (MBP) to an on state via its control node (G) to couple the low-voltage circuit device (LV) to the high-voltage source (VHVIN; BR, Cin); coupling a voltage sensing node (HV) to the high-voltage source (VHVIN; BR, Cin) via a pull-up resistor (RHV); and connecting the voltage sensing node (HV) and the control node (G) of the electronic switch (MBP). An intermediate electronic switch (SW1) is provided, which, in response to the voltage at the voltage sensing node (HV) reaching a threshold (VTH), switches (SW1_ON) the other electronic switch (SW1) to the on state to couple the voltage sensing node (HV) and the control node (G) of the electronic switch (MBP), and provides a charge pump (106) that couples to the current flow path of the electronic switch (MBP), and activates the charge pump (106) by using the other electronic switch (SW1) switched to the on state to pump charge (IGATE) from the current flow path of the electronic switch (MBP) to the control node (G) of the electronic switch (MBP) via the other electronic switch (SW1) switched to the on state.

[0155] The various embodiments described above can be combined to provide further embodiments. These and other changes can be made to the embodiments based on the detailed description above. Generally, the terminology used in the following claims should not be construed as limiting the claims to the specific embodiments disclosed in the specification and claims, but should be interpreted to include all possible embodiments and the full scope of the authorized equivalents of these claims. Therefore, the claims are not limited to this disclosure.

Claims

1. A circuit, comprising: a first electronic switch having a current flow path through the first electronic switch, the first electronic switch configured to be coupled between a high voltage node and a low voltage circuitry, the first electronic switch having a control node configured to switch the first electronic switch to a conductive state in which the first electronic switch electrically couples the low voltage circuitry to the high voltage node; a voltage sense node configured to be coupled to the high voltage node via a pull-up resistor; a second electronic switch coupled between the voltage sense node and the control node of the first electronic switch, the second electronic switch switchable to a conductive state in which the second electronic switch electrically couples the voltage sense node to the control node of the first electronic switch in response to receiving an enable signal; a comparator coupled to the voltage sense node and a threshold, the comparator configured to compare a voltage at the voltage sense node to the threshold and generate the enable signal in response to the voltage at the voltage sense node reaching the threshold; and a charge pump coupled to the current flow path of the first electronic switch and configured to be activated with the second electronic switch switched to the conductive state to pump charge from the current flow path of the first electronic switch to the control node of the first electronic switch via the second electronic switch switched to the conductive state.

2. The circuit of claim 1, comprising a charging capacitor coupled to the charge pump, the charging capacitor configured to be charged by the charge pump with charge in excess of the charge pumped to the control node of the first electronic switch.

3. The circuit of claim 1, wherein the charge pump is coupled to the voltage sense node and the charge pump is configured to pump charge from the current flow path of the first electronic switch to the voltage sense node.

4. The circuit of claim 1, comprising a latch circuit coupled between the comparator and the second electronic switch, the latch circuit configured to latch the enable signal in response to the voltage at the voltage sense node reaching the threshold.

5. The circuit of claim 1, further comprising a voltage clamp coupled between a ground node and the voltage sense node, wherein the voltage clamp is configured to clamp the voltage at the voltage sense node to a limit.

6. The circuit of claim 1, wherein the first electronic switch has a first node configured to be coupled to the high voltage node and a second node configured to be coupled to the low voltage circuitry, and wherein the charge pump is coupled to the current flow path of the first electronic switch at the second node.

7. The circuit of claim 1, wherein the first electronic switch and the second electronic switch are MOSFET transistors.

8. A power supply system, comprising: a high voltage source; a low voltage circuitry; and a circuit, comprising: a high voltage node coupled to the high voltage source; ​ ​ a first electronic switch having a current flow path through the first electronic switch, the first electronic switch coupled between the high voltage node and a low voltage circuitry, the first electronic switch having a control node configured to switch the first electronic switch to a conductive state in which the first electronic switch electrically couples the low voltage circuitry to the high voltage node; a pull-up resistor coupled between a voltage sense node and the high voltage node; a second electronic switch coupled between the voltage sense node and the control node of the first electronic switch, the second electronic switch switchable to a conductive state in which the second electronic switch electrically couples the voltage sense node to the control node of the first electronic switch in response to receiving an enable signal; a comparator coupled to the voltage sense node and a threshold, the comparator configured to compare a voltage at the voltage sense node to the threshold and generate the enable signal in response to the voltage at the voltage sense node reaching the threshold; and a charge pump coupled to the current flow path of the first electronic switch and configured to be activated with the second electronic switch switched to the conductive state to pump charge from the current flow path of the first electronic switch to the control node of the first electronic switch via the second electronic switch switched to the conductive state.

9. The power supply system of claim 8, comprising a charge capacitor coupled to the charge pump, the charge capacitor configured to be charged by the charge pump with charge in excess of charge pumped to the control node of the first electronic switch.

10. The power supply system of claim 8, wherein the charge pump is coupled to the voltage sense node and the charge pump is configured to pump charge from the current flow path of the first electronic switch to the voltage sense node.

11. The power supply system of claim 8, comprising a latch circuit coupled between the comparator and the second electronic switch, the latch circuit configured to latch the enable signal in response to the voltage at the voltage sense node reaching the threshold.

12. The power supply system of claim 8, further comprising a voltage clamp coupled between a ground node and the voltage sense node, wherein the voltage clamp is configured to clamp the voltage at the voltage sense node to a limit.

13. The power supply system of claim 8, wherein the first electronic switch has a first node configured to be coupled to the high voltage node and a second node configured to be coupled to the low voltage circuitry, and wherein the charge pump is coupled to the current flow path of the first electronic switch at the second node.

14. The power supply system of claim 8, wherein the first electronic switch and the second electronic switch are MOSFET transistors.

15. A method comprising: coupling a first electronic switch between a high voltage source and a low voltage circuit device, the first electronic switch having a current flow path through the first electronic switch and a control node; electrically coupling the low voltage circuit device to the high voltage source by switching the first electronic switch to an on state via the control node; coupling a voltage sense node to the high voltage source via a pull-up resistor; coupling a second electronic switch between the voltage sense node and the control node of the first electronic switch; coupling the voltage sense node to the control node of the first electronic switch by switching the second electronic switch to an on state in response to a voltage at the voltage sense node reaching a threshold value; coupling a charge pump to the current flow path of the first electronic switch; and activating the charge pump with the second electronic switch switched to the on state to pump charge from the current flow path of the first electronic switch to the control node of the first electronic switch via the second electronic switch switched to the on state.

16. The method of claim 15, comprising: charging a charge capacitor with charge in excess of charge pumped to the control node of the first electronic switch by the charge pump.

17. The method of claim 15, comprising: pumping charge from the current flow path of the first electronic switch to the voltage sense node by the charge pump.

18. The method of claim 15, comprising: latching an enable signal by a latch circuit coupled between a comparator and the second electronic switch in response to the voltage at the voltage sense node reaching the threshold value.

19. The method of claim 15, comprising: clamping the voltage at the voltage sense node to a limit value by a voltage clamp coupled between a ground node and the voltage sense node.

20. The method of claim 15, comprising: coupling a first node of the first electronic switch to the high voltage source; coupling a second node of the first electronic switch to the low voltage circuit device; and coupling the charge pump to the current flow path of the first electronic switch at the second node. ​ ​

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