Preventing thermal events in multi-phase voltage regulator device

Abstract

The present disclosure relates to preventing thermal events in a multi-phase voltage regulator device, in particular to a multi-phase voltage regulator device, a system including the multi-phase voltage regulator device, and a method. A multi-phase voltage regulator device (VRD) includes power stages coupled in parallel between a power input and a voltage regulator power output, each power stage including a power output stage and a control circuit connected to the power output stage. The VRD also includes a controller connected to the control circuitry of each power stage and a plurality of current sensors, where each current sensor measures an amount of current flowing through a power output stage of one of the power stages. The controller is configured to, in response to a measured amount of current flowing through any of the power stages being greater than a predetermined current threshold, apply a hard short circuit signal to the control circuits of one or more power stages. Upon receiving the hard short circuit signal, the control circuit is configured to maintain an output power stage of the power stage in a hard short circuit condition by connecting the power input to ground.

Description

Technical Field

[0001] This disclosure relates to the operation and control of multiphase voltage regulators. Background Technology

[0002] Multiphase voltage regulator devices (VRDs) are an efficient method for delivering power to high-current loads, such as central processing units (CPUs), application-specific integrated circuits (ASICs), and graphics processing units (GPUs). In a multiphase VRD, there are two or more power stages. Each power stage is used to incrementally supply energy to the load. The total current and energy from all power stages is far greater than the current and energy that a single power stage could provide.

[0003] A faulty power stage can fail at any time, such as during initial power-up, shortly after power-up, or even long afterward in a production data center. If a VRD suffers a catastrophic failure, smoke, fire, and / or open flame may occur. If the event is severe, these conditions could trigger fire suppression systems and cripple the entire data center. Therefore, it is crucial to implement protective measures to prevent catastrophic power stage failures from escalating into events that result in smoke, fire, or open flame.

[0004] All power stages in a VRD are controlled by a VRD controller, which can be implemented as a separate VRD controller chip. Under normal conditions, the VRD sends pulse-width modulation (PWM) pulses to the power stages to control the power output from the VRD to the load. The VRD controller constantly checks for anomalies in the VRD's operation and attempts to prevent runaway VRD failures. To prevent a power stage failure from developing into an undesirable event beyond the VRD's control, it is important to quickly disconnect the body voltage rail or input voltage rail (e.g., 12V) supplying energy to the faulty power stage. All modern multiphase VRD controllers can sense when a power stage is operating outside its normal operating conditions. For example, a multiphase VRD controller can detect if any power stage is experiencing current exceeding its established current limit, temperature exceeding its established temperature limit, or excessively high output voltage. When the VRD controller detects a serious problem with any power stage, it will attempt to disable all power stages to prevent the problem from escalating to the point where smoke, fire, or flame may occur. Typically, the VRD controller will disable all power stages by ceasing to send PWM pulses to them. Summary of the Invention

[0005] Some embodiments provide a multiphase voltage regulator device comprising: a plurality of power stages coupled in parallel between a power input and a voltage regulator power output, each power stage including a power output stage and control circuitry connected to the power output stage. The multiphase voltage regulator device further includes: a controller connected for communicating with the control circuitry of each power stage; and a plurality of current sensors, wherein each current sensor measures the amount of current flowing through the power output stage of one of the power stages. Furthermore, the controller is configured to apply a hard short-circuit signal to the control circuitry of one or more power stages in response to detecting that the measured current flowing through any of the power stages is greater than a predetermined current threshold, and wherein, for one or more power stages receiving the hard short-circuit signal, the control circuitry of the power stage is configured to maintain the output power stage of the power stage in a hard short-circuit condition by connecting the power input to a ground terminal in response to receiving the hard short-circuit signal.

[0006] Some embodiments provide a system comprising a multiphase voltage regulator device according to one or more embodiments described herein and a power supply having a power output connected to a power input of the multiphase voltage regulator device. The power input of the multiphase voltage regulator device is connected to a power output stage of each of the power stages, and the power supply automatically disconnects power from the multiphase voltage regulator device in response to detecting an overcurrent condition caused by a hard short-circuit condition in one or more power stages.

[0007] Some embodiments provide a system comprising a multiphase voltage regulator device according to one or more embodiments described herein, a power supply having a power output for supplying power to the multiphase voltage regulator device, and an electronic fuse connected between the power output and the power input of the multiphase voltage regulator device. The electronic fuse is configured to automatically disconnect power from the multiphase voltage regulator device in response to the electronic fuse detecting an overcurrent condition caused by a hard short circuit in one or more power stages.

[0008] Some embodiments provide a multiphase voltage regulator device comprising: a plurality of power stages coupled in parallel between a power input connector and a voltage regulator power output connector; a plurality of current sensors, each measuring the amount of current flowing through one of the power stages; and, further, field-effect transistors (FETs) not part of the power stages, having a source terminal connected to the power input connector, a drain terminal connected to a ground connector, and a gate. The multiphase voltage regulator device also includes a controller connected to each power stage, each current sensor, and the gate of the FET, wherein the controller is configured to: apply a hard short-circuit signal to the gate of the FET in response to detecting that a measured current flowing through any of the power stages exceeds a predetermined current threshold, and wherein the hard short-circuit signal turns on the FET and causes a hard short-circuit condition by electrically connecting the power input connector to the ground connector.

[0009] Some implementations provide a method comprising: controlling the operation of a plurality of power stages by a controller of a multiphase voltage regulator device, the plurality of power stages being coupled in parallel between a power input connector and a voltage regulator power output connector, wherein each power stage includes a power output stage and control circuitry connected to the power output stage and the controller. The method further comprises: monitoring current quantities measured by each of a plurality of current sensors by the controller, wherein each current sensor measures the current flowing through the power output stage of one of the power stages. Further, the method comprises: identifying, by the controller, that a measured current quantity flowing through the power output stage of any of the power stages is greater than a predetermined current threshold; and, in response to identifying that the measured current quantity through the power output stage of any of the power stages is greater than the predetermined current threshold, applying a hard short-circuit signal to the control circuitry of one or more of the power stages, wherein, for one or more power stages receiving the hard short-circuit signal, the control circuitry of the power stage is configured to: maintain the output power stage of the power stage in a hard short-circuit condition by electrically connecting the power input connector to a ground connector in response to receiving the hard short-circuit signal. Attached Figure Description

[0010] Figure 1 This is a diagram of a voltage regulator device (VRD) that includes multiple power stages and a VRD controller connected to each of the power stages.

[0011] Figure 2 This is a diagram of a single power stage, which consists of a high-side field-effect transistor (HS FET) coupled to the input voltage rail and a low-side field-effect transistor (LS FET) coupled to ground.

[0012] Figure 3 This is a diagram of an electronic fuse that cuts off power from the power source in response to the detection of an overcurrent condition.

[0013] Figure 4 This is a diagram of a voltage regulator device (VRD) according to an alternative implementation, wherein the VRD includes multiple power stages and a VRD controller connected to each of the power stages, as well as a dedicated FET for inducing a hard short circuit.

[0014] Figure 5 This is a perspective view of a dedicated FET inserted into a socket on a printed circuit board that supports a voltage regulator device. Detailed Implementation

[0015] Some embodiments provide a multiphase voltage regulator device comprising multiple power stages coupled in parallel between a power input and a voltage regulator power output, each power stage including a power output stage and control circuitry connected to the power output stage. The multiphase voltage regulator device also includes a controller connected for communication with the control circuitry of each power stage and multiple current sensors, wherein each current sensor measures the amount of current flowing through the power output stage of one of the power stages. Furthermore, the controller is configured to apply a hard short-circuit signal to the control circuitry of one or more power stages in response to detecting that a measured current flowing through any of the power stages is greater than a predetermined current threshold, and wherein, for the power stage receiving the hard short-circuit signal, the control circuitry of the power stage is configured to maintain the output power stage of the power stage in a hard short-circuit condition by connecting the power input to a ground terminal in response to receiving the hard short-circuit signal.

[0016] A multiphase voltage regulator device has its power input configured to connect to a power output from a power source, and its power output configured to connect to a load, such as one or more electronic components in a computer server, computing node, networking hardware, or other type of electronic device. The controller of the multiphase voltage regulator device is responsible for causing the control circuitry of each power stage to control the amount of power delivered to the voltage regulator's power output for use by the load. Furthermore, the controller monitors the amount of current passing through each power stage. For example, the controller may obtain current measurements from a current sensor within the power stage or from a separate current sensor connected to the output of the power stage. When the monitored current through each power stage is determined to be outside its normal operating range (i.e., greater than a predetermined current threshold), the controller applies a hard short-circuit signal to the control circuitry of one or more power stages. Specifically, the controller of the multiphase voltage regulator device may apply a hard short-circuit signal to any or all power stages in response to detecting that any power stage has a current exceeding an established current limit. Furthermore, the controller may be configured to apply a hard short-circuit signal to the control circuitry of one or more power stages in response to recognizing that a measured current flowing through any of the power stages is greater than a predetermined current threshold, without disabling one or more power stages.

[0017] The implementation described herein offers the following technical advantages: It responds to high current conditions in a power stage by detecting high current conditions that may be caused by a soft short circuit in a faulty power stage and intentionally inducing a hard short circuit in any or all power stages. A hard short circuit immediately causes the overcurrent protection limits in the upstream electronic fuse and / or PSU to be exceeded, such that the electronic fuse and / or PSU will rapidly disconnect power from all power stages (i.e., the 12V power rail) before the soft short circuit has time to generate high localized heating, smoke, combustion, or open flame. Intentionally inducing a hard short circuit causes a severe overcurrent condition, triggering the electronic fuse and / or power supply much faster than the point where localized heating and smoke, combustion, or open flame may occur.

[0018] A soft short circuit is defined as a short circuit between the input voltage (e.g., 12V) of a power stage and ground (GND) with a resistance low enough to cause a thermal event on the VRD power stage, but high enough that the resulting current draw will not be sufficient to trip an upstream electronic fuse or power supply unit (PSU) due to overcurrent protection limits. The resistance of a soft short circuit can be (but is not limited to) in the range of approximately tens to hundreds of mΩ. Over time, a soft short circuit will generate high localized heating, which can damage the power stage and nearby printed circuit boards and conductive traces. Localized heating may eventually lead to smoke, combustion, or open flame events. Ultimately, carbonization of materials (i.e., printed circuit board (PCB) traces, PCB vias, PCB epoxy, power stage packaging material, power stage die) may result in a resistance low enough that the amount of current flowing through the power stage will trip an upstream electronic fuse or PSU due to overcurrent protection. However, significant thermal damage may have already occurred by the time the overcurrent protection limit is reached. It should be recognized that the short circuit persists even if the controller commands the affected power stage to be disabled.

[0019] In contrast to a soft short circuit, a hard short circuit is defined as a short circuit (e.g., between the input voltage of a multiphase voltage regulator device and ground). A hard short circuit has lower resistance than a soft short circuit and causes current draw to trip the upstream electronic fuse or PSU due to overcurrent protection limitations. Intentionally creating a hard short circuit by clamping the power rail (e.g., a 12-volt (V) power rail) to ground (GND) through low-resistance paths on one or more power stages (e.g., some or all power stages connected in parallel) can potentially lead to additional electrical damage in one or more healthy power stages. However, preventing soft short circuits from becoming thermal events has a higher priority than preventing electrical damage to individual compute nodes or other individual units of the device, as smoke, burning, and / or fire events could ultimately cripple an entire rack or the entire data center. Furthermore, if a VRD's power stage has already exhibited a soft short circuit condition, the server motherboard must be replaced anyway, as the power stage is soldered to the motherboard and is unusable by the end user. Implementations utilize the capacity in at least the remaining good (healthy) power stages to indirectly shut down the server even if an electrical short circuit has been detected.

[0020] In some embodiments of multiphase voltage regulator devices, current sensors that measure the current flowing through the power output stage of each power stage can be included within the power stage. With each current sensor included within one or more corresponding power stages, the current sensors can be connected to the control circuitry of the same power stage and report the measured current to the control circuitry. Therefore, the control circuitry of each power stage can then report the measured current to the controller. Alternatively, the current sensors for each power stage can be external to a separate power stage but still connected to the controller, such that the measured current for each power stage is output to the controller from the corresponding current sensor.

[0021] In some implementations, the multiphase voltage regulator device may also include a dedicated conductor connecting from the controller to the control circuitry of each power stage for sending a hard short-circuit signal to each power stage. This dedicated conductor for the hard short-circuit signal may be separate from any other communication lines between the controller and the control circuitry, which may be used with other control signals such as pulse width modulation (PWM) signals. This dedicated control signal line (e.g., a “HARDSHORT” conductor trace) connects from the controller to each of the power stages to ensure that hard short-circuit operation is completed relatively quickly and reliably. In one option, the dedicated conductor includes a loop, a first branch connecting the loop to the controller, and, for each power stage, a branch connecting the loop to the control circuitry of that power stage. Including the loop in the dedicated conductor provides a degree of redundancy because the connection to some or all of the power stages is maintained even if one end of the dedicated conductor (i.e., the HARDSHORT conductor trace) is damaged. For example, a portion of the dedicated conductor may have been damaged due to a power stage failure.

[0022] In some implementations, each power stage of the multiphase voltage regulator device may include an internal pull-down resistor that connects a dedicated conductive line to ground. The internal pull-down resistor pulls the dedicated conductive line down to ground potential, preventing the power stage from being unintentionally hard-short-circuited.

[0023] In some implementations, each power stage (e.g., its power output stage) may include a high-side (HS) field-effect transistor (FET) having a source terminal connected to a power supply, a low-side (LS) FET having a drain terminal connected to ground, a power output terminal connected between the drain terminal of the HS FET and the source terminal of the LS FET, and an inductor connected between the power output terminal and a load. Furthermore, each power stage may include a first driver having an output connected to the gate of the HS FET and a second driver having an output connected to the gate of the LS FET. Control circuitry for each power stage is connected to an input of the first driver to control whether the first driver applies a signal to the gate of the high-side FET, and is connected to an input of the second driver to control whether the second driver applies a signal to the gate of the low-side FET.

[0024] The control circuitry for each power stage can perform various functions, including direct control of the first and second drivers (and therefore the HS FET and LS FET) and processing of current measurements output by the current sensors used for the power stage.

[0025] When the power stage receives a hard short-circuit signal from the controller, the control circuitry for the power stage will implement a hard short circuit, for example, by simultaneously turning on both the HS FET and LS FET to drive the power stage, and thus drive the multiphase voltage regulator device itself into a hard short-circuit and overcurrent condition. By rapidly driving the voltage regulator device into a high-current condition, the upstream electronic fuse or power supply unit (PSU) will quickly sense the high current condition and cut off power to the voltage regulator device to prevent or terminate a thermal event. For example, in the case where the multiphase voltage regulator device is a component of a server, a high current condition could cause the entire server to shut down immediately. However, rapidly and intentionally inducing a high current condition will quickly trigger a power cut-off from the multiphase voltage regulator device and prevent catastrophic failures in the multiphase voltage regulator device that could lead to smoke, fire, or open flame accidents.

[0026] When the controller of a multiphase voltage regulator outputs a hard short-circuit signal, the hard short-circuit signal is preferably sent to all power stages, including both "good power stages" and damaged / damaged soft-short-circuited power stages, and received and implemented by as many power stages as possible capable of doing so. However, implementations may cause a hard short circuit in any of one or more power stages (damaged power stages and / or one or more good power stages), as long as the resulting hard short circuit leads to a high current condition sufficient to trigger the upstream electronic fuse and / or PSU overcurrent protection. Hard shorting all power stages results in maximum current being drawn from one or more upstream power sources, and thus ensures that the electronic fuse and / or one or more power sources will quickly sense the short circuit and disconnect power to the voltage regulator.

[0027] In some embodiments of a multiphase voltage regulator device, each power stage includes a first driver and a second driver, wherein the first driver has a first driver input connected to control circuitry and a first driver output connected to the gate of a high-side field-effect transistor, and wherein the second driver has a second driver input connected to control circuitry and a second driver output connected to the gate of a low-side field-effect transistor. In one option, in response to a hard short-circuit signal, the control circuitry of each power stage receiving the hard short-circuit signal can be configured to maintain the output power stage of the power stage in a hard short-circuit state by causing the first driver to apply a first output voltage to the gate of the HSFET to turn on the HS FET and causing the second driver to apply a second output voltage to the gate of the LS FET to turn on the LS FET. Preferably, the hard short circuit is maintained until the voltage regulator no longer receives power.

[0028] Some implementations provide a system comprising a multiphase voltage regulator device and a power supply according to one or more embodiments described herein, the power supply having a power output connected to a power input of the multiphase voltage regulator device. The power input of the multiphase voltage regulator device is connected to a power output stage of each of the power stages, and in response to the power supply detecting an overcurrent condition caused by a hard short circuit in one or more power stages, the power supply automatically disconnects power from the multiphase voltage regulator device. The overcurrent condition is characterized by a current exceeding the overcurrent protection limit of the power supply. Therefore, keeping the output power stages of one or more power stages in a hard short circuit condition by the control circuitry will place the power supply in an overcurrent condition relatively quickly (if not immediately). Specifically, a hard short circuit causes the path between the power supply and ground to have a lower resistance than a soft short circuit. Therefore, a hard short circuit condition preferably causes the power supply to disconnect power from the multiphase voltage regulator device in a shorter time than waiting for a soft short circuit condition in any power stage to disconnect power from the multiphase voltage regulator device. In one option, the system may also include a computer server (or other computing or networking hardware), wherein the multiphase voltage regulator device has power output to provide power to multiple components of the computer server to operate, and wherein automatic power cut-off to the multiphase voltage regulator device prevents the computer server from experiencing smoke, fire or open flame events.

[0029] Some embodiments provide a system comprising a multiphase voltage regulator device according to one or more embodiments described herein, a power supply having a power output for supplying power to the multiphase voltage regulator device, and an electronic fuse connected between the power output and the power input of the multiphase voltage regulator device. The electronic fuse is configured to automatically disconnect power from the multiphase voltage regulator device in response to the electronic fuse detecting an overcurrent condition caused by a hard short circuit in one or more power stages.

[0030] Some implementations provide alternative multiphase voltage regulator devices comprising multiple power stages coupled in parallel between a power input connector and a voltage regulator power output connector. The multiphase voltage regulator device also includes multiple current sensors, each measuring the amount of current flowing through one of the power stages. Furthermore, the multiphase voltage regulator device includes a dedicated or external FET that is not part of the power stages, wherein the dedicated FET has a source terminal connected to the power input connector, a drain terminal connected to a ground connector, and a gate. The multiphase voltage regulator device also includes a controller connected to each power stage, each current sensor, and the gate of the dedicated FET, wherein the controller is configured to apply a hard short-circuit signal to the gate of the dedicated FET in response to detecting that a measured current flowing through any of the power stages is greater than a predetermined current threshold, and wherein the hard short-circuit signal turns on the dedicated FET and causes a hard short-circuit condition by electrically connecting the power input connector to the ground connector. The controller is preferably connected to the dedicated FET via a driver, wherein the driver input is connected to the controller and the driver output is connected to the gate of the dedicated FET.

[0031] Alternative multiphase voltage regulator devices can control dedicated FETs in the same manner as any previous implementation controlling the power output stage to place the power output stage in a hard short-circuit condition. However, the controller can have dedicated conductive lines to the dedicated FET without requiring any changes to the construction or operation of the power stage. For example, the controller can have a new output for sending a hard short-circuit signal to a dedicated FET that is not part of any power stage. Since the dedicated FET is not part of any power stage, a hard short circuit can be created by turning on the dedicated FET without needing to turn on both the HS FET and LS FET of one or more power stages as in previous implementations. Turning on this external dedicated FET connects the power rail (i.e., the 12V source) to ground, which relatively quickly leads to an overcurrent condition at the upstream electronic fuse or power supply. The power supply or electronic fuse will then relatively quickly or immediately disconnect power to the multiphase voltage regulator device.

[0032] In some implementations of alternative multiphase voltage regulator devices, the power stage, current sensor, dedicated FET, and controller can be mounted on a printed circuit board (PCB), where the dedicated FET is fixed in a socket on the PCB, making it field-replaceable. Therefore, if power to the voltage regulator is cut off before any power stage fails, the dedicated FET can be replaced if it fails during use, potentially increasing the PCB's lifespan.

[0033] In some implementations, the hard short-circuit signal issued by the controller can be a Power Good (PGOOD) signal. The Power Good (PGOOD) signal is an existing signal that can be used in place of the dedicated HARDSHORT signal. This simplifies the control logic used by the controller but may not require any changes to the physical configuration of the multiphase voltage regulator device described herein.

[0034] Some implementations provide a method comprising: a controller of a multiphase voltage regulator device controlling the operation of a plurality of power stages coupled in parallel between a power input connector and a voltage regulator power output connector, wherein each power stage includes a power output stage and control circuitry connected to the power output stage and the controller. The method further comprises: the controller monitoring a current quantity measured by each of a plurality of current sensors, wherein each current sensor measures a current quantity through the power output stage of one of the power stages. Further, the method comprises: the controller identifying that a measured current quantity flowing through the power output stage of any power stage is greater than a predetermined current threshold, and in response to identifying that the measured current quantity flowing through the power output stage of any power stage is greater than the predetermined current threshold, applying a hard short-circuit signal to the control circuitry of one or more power stages, wherein for one or more power stages receiving the hard short-circuit signal, the control circuitry of the power stage is configured to maintain the output power stage of the power stage in a hard short-circuit condition by electrically connecting the power input connector to a ground connector in response to receiving the hard short-circuit signal.

[0035] Operation of any method disclosed herein can be implemented as a computer program product comprising a non-volatile computer-readable medium and non-transitory program instructions implemented therein, the program instructions being configured to be executed by a processor to cause the processor to perform operations. For example, a controller may include at least one non-volatile storage device storing program instructions and at least one processor configured to process the program instructions.

[0036] Figure 1This is a diagram of a system 10 including a multiphase voltage regulator device (VRD) 20 having multiple power stages (six shown) 30 and a VRD controller 50 connected to each of the power stages 30. System 10 also includes a power supply 12 for supplying power to the multiphase voltage regulator device 20, which regulates the voltage of the power ultimately supplied to a load 14. For example, the load 14 may be a set of components in a server or other computing or networking hardware. In system 10, current from the power supply 12 reaches the multiphase voltage regulator device 20 via an optional electronic fuse 18 and a power cable 19. Within the multiphase voltage regulator device 20, current is supplied to each of the power stages (six shown) 30, and the output current from each of the power stages 30 is delivered to the load 14 via line 17. To support the operation of the multiphase voltage regulator device 20, each power stage 30 also has a connection 13 leading to ground (GND) 15.

[0037] The power supply 12 may have an overcurrent protection circuit 16, and / or the system may include a separate overcurrent protection circuit, such as an electronic fuse 18, connected in series between the power supply 12 and the multiphase voltage regulator device 20. However, the system 10 should have at least one overcurrent protection circuit 16, 18 to automatically disconnect power to the multiphase voltage regulator device 20 at any time when the current drawn by the multiphase voltage regulator device 20 exceeds the overcurrent protection limit established by the overcurrent protection circuit.

[0038] During normal operation of the multiphase voltage regulator device 20, the controller 50 communicates with each of the power stages 30 via communication line 52 to control or implement how each of the power stages 30 delivers current to the load 14. For example, the controller 50 may provide a pulse width modulation (PWM) signal to each power stage to control the duty cycle of the switches within the power stage 30, thereby controlling the average voltage output to the load 14. The same or similar (parallel) communication line 52 may also provide the controller 50 with current measurements from each power stage 30.

[0039] However, during the lifespan of the multiphase voltage regulator device 20, a faulty power stage 30 may experience a soft short circuit at any time. By monitoring the amount of current flowing through each power stage 30, the controller 50 can detect when the current exceeds a high current threshold, indicating the presence of a soft short circuit in a particular power stage 30. The controller 50 can then send a hard short circuit signal to the power stage 30 via a dedicated hard short circuit signal line 54. An optional loop 56 can be included in the dedicated hard short circuit signal line 54 to provide a degree of redundancy to the path of line 54 in the event that a portion of the path of line 54 is damaged by an developing soft short circuit. For example, if any single point in the loop is damaged and can no longer send a hard short circuit signal, the hard short circuit signal can still reach each of the power stages 30 via another path around loop 56. As shown, the dedicated hard short circuit signal line 54 also includes branches 58 leading from loop 56 to each individual power stage 30.

[0040] Figure 2 This is a diagram of a single power stage 30 with control circuitry 40 and a power output stage 32. The power output stage 32 includes a high-side field-effect transistor (HS FET) 34 and a low-side field-effect transistor (LS FET) 36. The HS FET 34 has a source terminal connected to the input voltage rail (or body voltage rail) 19, and the LS FET 36 has a drain terminal coupled to ground terminal (or ground) 15. The drain terminal of the HS FET 34 and the source terminal of the LS FET 36 are connected together at point 33, where current is transferred to the inductor 38 before being output to the load 14. Although power stage 30 is shown as having p-channel enhancement-mode FETs 34 and 36, it should be understood that in some embodiments, depending on the design of VRD 20 and / or the power requirements of load 14, different types of transistors (e.g., n-channel) may be used to implement HS FET 34 and / or LS FET 36. Furthermore, power stage 30 and its HS FET 34 and LS FET 36 may be configured differently (e.g., the orientation of the source and drain terminals of each FET may differ). Figure 2 (The orientation shown). In some embodiments, as an example, the HS FET 34 and / or LS FET 36 may be implemented using silicon (Si), silicon carbide (SiC), or gallium nitride (GaN). A current sensor 46 is also disposed in or along the power output to the load 14. The current sensor 46 measures the amount of current output by the power output stage 32 and transmits the measured current to the control circuit 40. The control circuit 40 then transmits the measured current to the controller 50, for example, via communication line 52.

[0041] Current sensor 46 may include circuitry comprising a sensing resistor and a sensor for measuring the voltage drop across the sensing resistor, wherein the current (I) is equal to the voltage (V) divided by the resistance (R). Alternatively, current sensing may be performed using a sensor for measuring the voltage drop across inductor 38. Furthermore, current sensing may be performed using a sensor for measuring the voltage drop across the drain and source pins of HS FET 34 and / or LS FET 36. FETs 34, 36 will have an on-resistance value (“Rds on”), which can be used to measure the current through the FET by measuring the voltage across the drain and source. However, the on-resistance value can be very small, resulting in a small voltage and susceptibility to errors due to noise. Additionally, power stage 30 may include a current mirror circuit that replicates the current through output power stage 32 and a current sensor within the current mirror circuit. In any of these configurations, the measured current is transmitted to control circuitry 40 and forwarded to controller 50.

[0042] During normal operation of the multiphase voltage regulator device 20, the control circuit 40 of the power stage 30 receives control signals, such as pulse width modulation signals, from the controller 50 via communication line 52. The control circuit 40 receives these control signals and applies them to the inputs of the first driver 42 and / or the second driver 44. The output of the first driver 42 is connected to the gate of the HSFET 34, and the output of the second driver is connected to the gate of the LSFET 36. Therefore, the control signals from the controller 50 can control the duty cycle or pulse width modulation of the HSFET 34 and / or the LSFET 36 to provide the desired voltage to the load 14.

[0043] If controller 50 determines that the current measured by current sensor 46 is greater than a high current threshold, the controller will provide a command or signal (e.g., a hard short signal) to control circuit 40 via communication line 58 to turn on both FETs 34 and 36. Pull-down resistor 59 connects dedicated conductive line 58 to ground terminal 15 to pull the dedicated conductive line down to ground potential, preventing power stage 30 from unintentionally hard short-circuiting. Simultaneously turning on and holding both FETs 34 and 36 in this state creates a low-resistance path between power line 12 and ground terminal 15, clamping power line 12 to ground terminal 15, resulting in a hard short circuit. For example, the low-resistance path may have a resistance of less than 10 mΩ, less than 1 mΩ, or much less than 1 mΩ, which is lower (and potentially much lower) than the tens to hundreds of mΩ resistance associated with a soft short circuit. This low-resistance path will cause an overcurrent condition, which will be triggered by power supply 12 or electronic fuse 18 (see...). Figure 1The power supply 12 or electronic fuse 18 will automatically and quickly or immediately cut off the power flowing to the multiphase voltage regulator device 20.

[0044] In one option, controller 50 may provide a HARDSHORT command or signal via communication line 58 while simultaneously stopping the provision of control signals or PWM signals via communication line 52. In another option, controller 50 may provide a HARDSHORT command or signal via communication line 58 without stopping the provision of control signals or PWM signals via communication line 52, or independently of stopping the provision of control signals or PWM signals via communication line 52, because performing the cessation of the provision of control signals or PWM signals via communication line 52 may cause calculation time and / or activity (e.g., by controller 50), delaying the shutdown of the multiphase voltage regulator device 20, and increasing the risk of damage to load 14 and / or other components in or outside system 10.

[0045] Figure 3 This is a diagram of an overcurrent protection circuit 60 in the form of an electronic fuse 18, which will cut off power from the power source 12 in response to detecting an overcurrent condition. The overcurrent protection circuit 60 can have any available design, and the embodiments disclosed herein are not limited to the disclosed design. Alternatively, the power source 12 may include a similar overcurrent protection circuit 60, making a separate electronic fuse 18 unnecessary.

[0046] As shown in the figure, the electronic fuse 18 includes a control logic device 62 and a current sensing resistor (R). sense The control logic device 62 monitors the current sensing resistor 64 to obtain a current measurement value and controls the field-effect transistor 66 via a connection to the gate of the field-effect transistor 66. Therefore, when the control logic device 62 detects that the measured current from the current sensing resistor 64 has exceeded the overcurrent protection limit, the control logic device 62 will assert or de-assert a signal to the gate of the field-effect transistor 66, thereby causing the field-effect transistor 66 to turn off (open circuit). Once the field-effect transistor 66 is turned off, power from the power supply 12 cannot reach the multiphase voltage regulator device 20.

[0047] Figure 4 This is a diagram of a multiphase voltage regulator device (VRD) 70 according to an alternative embodiment, wherein the multiphase voltage regulator device 70 includes a plurality of power stages 30 and a controller 50 connected to each of the power stages 30, and a dedicated FET 80 for inducing a hard short circuit. The power stages 30 may be compared with reference to... Figure 1 and Figure 2 The power stage 30 described is the same.

[0048] The alternative multiphase voltage regulator device 70 includes a dedicated FET 80, which is not part of the power stage 30 and is not included in the... Figure 1 In the voltage regulator device 20 shown, the dedicated FET 80 has a source terminal connected to the power input 19 (labeled 12V), a drain terminal connected to ground (GND15), and a gate connected to the dedicated hard short-circuit signal line 74. Figure 4 The dedicated FET 80 is shown as a p-channel enhancement-mode FET, but with... Figure 2 Similar to FETs 34 and 36, in some implementations, the dedicated FET 80 can be... Figure 4 Different types of dedicated FET 80 are shown. Controller 50 is configured to apply a hard short-circuit signal to the gate of dedicated FET 80 on dedicated hard short-circuit line 74 in response to detecting that the measured current through any power stage exceeds a predetermined current threshold. The hard short-circuit signal turns on dedicated FET 80 and induces a hard short-circuit condition by electrically connecting power input 19 to ground 15. The controller can be connected to dedicated FET 80 via a driver (not shown), where the driver input is connected to the controller and the driver output is connected to the gate of dedicated FET 80. Thus, turning on dedicated FET 80 connects the power rail (i.e., the 12V source) to ground, which quickly leads to an overcurrent condition at upstream electronic fuse 18 or power supply 12. Power supply 12 or electronic fuse 18 then immediately cuts off power to alternative multiphase voltage regulator device 70.

[0049] In one option, the dedicated FET 80 can be mounted in a socket (not shown) on a printed circuit board, thereby enabling the dedicated FET 80 to be field-replaceable (see [link to relevant documentation]). Figure 5 ).

[0050] In one option, the hard short-circuit signal applied by controller 50 to dedicated hard short-circuit circuit 74 can be the HARDSHORT signal discussed above. In another option, the hard short-circuit signal applied by controller 50 to dedicated hard short-circuit circuit 74 can be a power good (PGOOD) signal. The presence (or absence) of the PGOOD signal on dedicated hard short-circuit circuit 74 can cause dedicated FET 80 to turn on or conduct, thereby causing the hard short-circuit condition discussed above.

[0051] Figure 5This is a perspective view of a dedicated FET 80 inserted into a socket 82 on a printed circuit board supporting the voltage regulator device 70. The socket 82 includes three connectors 84, each configured to selectively receive pins 86 of the dedicated FET 80. One connector 84 connects the source of the dedicated FET 80 to power input line 19, one connector 84 connects the drain of the dedicated FET 80 to ground terminal 15, and one connector 84 connects the gate of the FET 80 to a dedicated hard-short circuit 74 from a controller (not shown). The illustrated configuration of the dedicated FET 80 and socket 82 allows for quick manual replacement of the dedicated FET 80 in the field.

[0052] As those skilled in the art will understand, implementations may take the form of systems, methods, or computer program products. Therefore, implementations may take the form of entirely hardware implementations, entirely software implementations (including firmware, resident software, microcode, etc.), or implementations combining software and hardware aspects, all of which may be collectively referred to herein as “circuit,” “module,” or “system.” Furthermore, implementations may take the form of computer program products embodied in one or more computer-readable media having computer-readable program code implemented thereon.

[0053] Any combination of one or more computer-readable storage media may be used. Computer-readable storage media can be, for example, but not limited to, electronic, magnetic, optical, electromagnetic, infrared, or semiconductor systems, apparatuses, or devices, or any suitable combination thereof. More specific examples (a non-exhaustive list) of computer-readable storage media may include: portable computer disks, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), portable optical disc read-only memory (CD-ROM), optical storage devices, magnetic storage devices, or any suitable combination thereof. In the context of this document, computer-readable storage media can be any tangible medium that can contain or store programs used by or in conjunction with an instruction execution system, apparatus, or device. Furthermore, for the avoidance of doubt, any program instructions or code implemented on such computer-readable storage media (including forms referred to as volatile memory) that are not transient signals are considered “non-transient”.

[0054] Program code implemented on a computer-readable storage medium can be transmitted using any suitable medium, including but not limited to wireless, wired, fiber optic cable, RF, or any suitable combination thereof. Computer program code for performing various operations can be written in any combination of one or more programming languages—including object-oriented programming languages ​​such as Java, Smalltalk, C++, etc., and conventional procedural programming languages ​​such as the "C" programming language or similar programming languages. The program code can be executed entirely on the user's computer, partially on the user's computer, as a standalone software package, partially on the user's computer and partially on a remote computer, or entirely on a remote computer or server. In the latter scenario, the remote computer can be connected to the user's computer via any type of network, including a local area network ("LAN") or a wide area network ("WAN"), or can be connected to an external computer (e.g., through the use of the Internet provided by an Internet service provider).

[0055] Implementation methods can be described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products. It is understood that each block in the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions / actions specified in one or more blocks of the flowchart illustrations and / or block diagrams.

[0056] These computer program instructions may also be stored on a computer-readable storage medium rather than as transient signals, so that the program instructions can instruct a computer, other programmable data processing apparatus or other device to function in a particular manner, and cause the program instructions stored in the computer-readable storage medium to produce an article of art.

[0057] Computer program instructions may also be loaded onto a computer, other programmable data processing apparatus or other equipment to cause a series of operational steps to be performed on the computer, other programmable apparatus or other equipment to produce a computer-implemented process, such that the instructions, which execute on the computer or other programmable apparatus, provide a process that implements the function / action specified in one or more boxes of a flowchart and / or block diagram.

[0058] The flowcharts and block diagrams in the figures illustrate the architecture, functionality, and operation of possible implementations of systems, methods, and computer program products. In this regard, each box in a flowchart or block diagram may represent a module, segment, or portion of instructions, which includes one or more executable instructions for implementing a specified logical function. It should also be noted that in some alternative implementations, the functions indicated in the boxes may not occur in the order shown in the figures. For example, two boxes shown consecutively may actually be executed substantially simultaneously, or these boxes may sometimes be executed in reverse order, depending on the functions involved. It should also be noted that each box in the block diagrams and / or flowcharts, and combinations of boxes in the block diagrams and / or flowcharts, may be implemented by a system based on dedicated hardware or a combination of dedicated hardware and computer instructions that performs the specified function or action.

[0059] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of this disclosure. As used herein, the singular forms (“(a)”, “(an)”) and “the” are also intended to include the plural forms unless the context clearly indicates otherwise. It will also be understood that, when used in this specification, the terms “conmprises” and / or “comprising” specify the presence of stated features, integers, steps, operations, elements, components, and / or groups, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof. The terms “preferred,” “ideally,” “preferred,” “optionally,” “may,” and similar terms are used to indicate that the mentioned item, condition, or step is an optional (not required) feature of the embodiment.

[0060] All means or steps plus functional elements in the appended claims are intended to include any structure, material, action, and equivalent that, in combination with other elements of the specifically claimed claims, perform the function. Embodiments have been presented for purposes of illustration and description, but are not intended to be exhaustive or limited to the embodiments disclosed. Many modifications and variations will be apparent to those skilled in the art upon reading this disclosure. The disclosed embodiments have been chosen and described as non-limiting examples to enable others skilled in the art to understand these embodiments and other embodiments involving modifications suitable for particular implementations.

Claims

1. A multiphase voltage regulator apparatus comprising: a plurality of power stages coupled in parallel between a power input and a voltage regulator power output, each power stage comprising a power output stage and a control circuit connected to the power output stage; a controller connected for communication with the control circuit of each power stage; and a plurality of current sensors, each configured to measure an amount of current flowing through the power output stage of a respective one of the power stages, wherein the controller is configured to apply a hard short signal to the control circuit of one or more of the power stages in response to identifying that the measured amount of current flowing through any of the plurality of power stages is greater than a predetermined current threshold, and wherein the control circuit of each power stage receiving the applied hard short signal is configured to, in response to receiving the applied hard short signal, hold the output power stage of the power stage in a hard short condition by connecting the power input to a ground terminal.

2. The multiphase voltage regulator apparatus of claim 1, wherein, For each of the power stages, the current sensor configured to measure an amount of current flowing through the power output stage is included in the power stage and is configured to report the amount of current to the control circuit of the power stage, and wherein for each of the power stages, the control circuit is configured to report the amount of current to the controller.

3. The multiphase voltage regulator apparatus of claim 1, wherein, The controller is configured to provide a control signal to each of the plurality of power stages, and wherein the controller is configured to apply the hard short signal to the control circuit of one or more of the power stages in response to identifying that the measured amount of current flowing through any of the power stages is greater than the predetermined current threshold without stopping providing the control signal to the one or more power stages.

4. The multiphase voltage regulator apparatus of claim 1, wherein, The one or more of the power stages to which the controller applies the hard short signal comprises all of the plurality of power stages of the multiphase voltage regulator apparatus.

5. The multiphase voltage regulator apparatus of claim 4, further comprising: a dedicated conductive line connected from the controller to the control circuit of each power stage for applying the hard short signal to each power stage.

6. The multiphase voltage regulator apparatus of claim 5, wherein, The dedicated conductive line comprises a loop, a first branch connecting the loop to the controller, and for each of the power stages, a branch connecting the loop to the control circuit of the power stage.

7. The multiphase voltage regulator apparatus of claim 5, wherein, Each power stage comprises an internal pull-down resistor connecting the dedicated conductive line to ground.

8. The multiphase voltage regulator apparatus of claim 1, wherein, Each power output stage comprises a high-side field effect transistor having a source terminal connected to the power source, a low-side field effect transistor having a drain terminal connected to ground, a power output terminal connected between a drain terminal of the high-side field effect transistor and a source terminal of the low-side field effect transistor, and an inductor connected between the power output terminal and the load.

9. The multiphase voltage regulator apparatus of claim 8, wherein, Each power stage includes a first driver and a second driver, where the first driver has a first driver input connected to the control circuit and a first driver output connected to a gate of the high-side field effect transistor, and where the second driver has a second driver input connected to the control circuit and a second driver output connected to a gate of the low-side field effect transistor.

10. The multiphase voltage regulator apparatus of claim 9, wherein, For each power stage, the control circuit of the power stage is configured to maintain an output power stage of the power stage in the hard short condition by causing the first driver to apply a first output voltage to the gate of the high-side field effect transistor to turn on the high-side field effect transistor and causing the second driver to apply a second output voltage to the gate of the low-side field effect transistor to turn on the low-side field effect transistor.

11. A system comprising: the multiphase voltage regulator device of claim 1; and a power supply having a power supply output connected to a power input of the multiphase voltage regulator device, where the power input is connected to a power output stage of each of the power stages, and where the power supply is configured to remove power from the multiphase voltage regulator device in response to the power supply detecting an overcurrent condition caused by a hard short condition of the one or more power stages.

12. The system of claim 11, wherein, maintaining the output power stage of the one or more power stages in the hard short condition places the power supply in the overcurrent condition.

13. The system of claim 11, wherein, the hard short causes a path between the power supply and ground to have a lower resistance than a soft short.

14. The system of claim 11, further comprising: a computer server, where the voltage regulator power output provides power to operate a plurality of components of the computer server.

15. The system of claim 11, wherein, the overcurrent condition is characterized by an amount of current that is greater than an overcurrent protection limit of the power supply.

16. A system comprising: the multiphase voltage regulator device of claim 1; a power supply having a power supply output for supplying power to the multiphase voltage regulator device; and an electronic fuse connected between the power supply output and a power input of the multi-stage voltage regulator device, where the electronic fuse is configured to remove power from the multi-stage voltage regulator device in response to the electronic fuse detecting an overcurrent condition caused by a hard short condition of the one or more power stages.

17. A multiphase voltage regulator device comprising: a plurality of power stages coupled in parallel between a power input connector and a voltage regulator power output connector; a plurality of current sensors, each current sensor measuring an amount of current flowing through one of the power stages; a dedicated field effect transistor separate from the power stages, where the dedicated field effect transistor has a source terminal connected to the power input connector, a drain terminal connected to a ground connector, and a gate; and a control circuit connected to the dedicated field effect transistor and the plurality of power stages, where the control circuit is configured to: cause the dedicated field effect transistor to turn on in response to the control circuit detecting a hard short condition of the one or more power stages. a controller connected to each power stage, each current sensor, and the gate of the dedicated field effect transistor, wherein the controller is configured to apply a hard short signal to the gate of the field effect transistor in response to identifying that a measured amount of current flowing through any of the power stages is greater than a predetermined current threshold, and wherein the hard short signal causes the dedicated field effect transistor to turn on and results in a hard short condition by electrically connecting the power input connector to the ground connector.

18. The multiphase voltage regulator apparatus of claim 17, wherein, the power stages, current sensors, dedicated field effect transistor, and controller are mounted on a printed circuit board, and wherein the field effect transistor is secured in a socket on the printed circuit board such that the external field effect transistor is field replaceable.

19. The multiphase voltage regulator apparatus of claim 17, wherein, the hard short signal applied to the gate of the dedicated field effect transistor is a power good signal.

20. A method comprising: controlling, by a controller of a multiphase voltage regulator device, operation of a plurality of power stages of the multiphase voltage regulator device, the plurality of power stages coupled in parallel between a power input connector and a voltage regulator power output connector, wherein each power stage includes a power output stage and a control circuit connected to the power output stage and the controller; monitoring, by the controller, an amount of current measured by each of a plurality of current sensors, each current sensor configured to measure an amount of current flowing through the power output stage of a respective one of the plurality of power stages; identifying, by the controller, that the measured amount of current flowing through the power output stage of any of the power stages is greater than a predetermined current threshold; and applying, by the controller, a hard short signal to the control circuit of one or more of the power stages in response to identifying that the measured amount of current flowing through the power output stage of any of the power stages is greater than the predetermined current threshold, wherein for one or more of the power stages that receive the hard short signal, the control circuit of the power stage is configured to maintain the output power stage of the power stage in a hard short condition in response to receiving the hard short signal by electrically connecting the power input connector to a ground connector.

Images