Embedded substrate voltage regulator

Abstract

Embodiments of the present disclosure relate to embedded substrate voltage regulators. A voltage converter inlay module is provided for embedding within a package substrate and is configured to power a processor or similar digital circuit mounted to the package substrate. The package substrate is typically mounted to a circuit board or the like. The circuit board provides high voltage, low current power to the voltage converter module which in turn provides low voltage, high current power to the processor. The voltage converter inlay provides most of the vertical current conduction from the circuit board to the processor, thereby reducing conduction losses caused by lateral current conduction. The location of the voltage converter inlay between the circuit board and the microprocessor minimizes the radiation of electromagnetic interference. Since the voltage converter inlay draws a relatively low level of current, the number of terminals allocated for providing power to the package substrate can be minimized. The high current power required by the processor is confined within the package substrate.

Description

TECHNICAL FIELD

[0001] This application relates to voltage regulators that are embedded within a substrate and provide vertical current flow to power microprocessors or similar devices. BACKGROUND

[0002] Digital-intensive integrated circuits (ICs), including central processing units (CPUs), graphics processing units (GPUs), and application specific integrated circuits (ASICs), continue to decrease silicon feature size to increase speed, decrease circuit size, and / or increase performance. Such smaller silicon feature sizes require lower power supply voltages due to the lower breakdown voltages inherently associated with decreased feature sizes. As the required voltages decrease, current supply levels need to increase to maintain similar power consumption and processor performance. These higher current levels in turn often require additional terminals to power the IC (e.g., CPU). The additional power terminals result in larger IC substrate packages and sockets, increasing cost and decreasing density.

[0003] The higher currents described above result in higher conduction losses between the power supply (e.g., voltage regulator) and the CPU or similar IC. These conduction losses can be constrained by minimizing the length of the circuit board traces and associated resistances that power the CPU or similar load. In typical implementations, the voltage regulator(s) can be located on the circuit board and close to the load (e.g., CPU) in order to minimize conduction losses.

[0004] Some recent implementations attempt to further decrease conduction losses by integrating the voltage regulator into the same die as the digital IC (e.g., CPU). Although such implementations provide low conduction losses, these implementations have not gained much traction due to high cost, high risk, and other issues. Specifically, silicon processes optimized for digital circuits are typically not suitable for implementing high power transistors due to the demands of the voltage regulator. Thus, a voltage regulator integrated in a primarily digital silicon die can suffer in performance (including power efficiency of switching), can interfere with the digital portion of the die, can decrease the overall yield of the die, etc.

[0005] There is a need for circuitry and devices that decrease conduction losses between a power supply and an associated load without requiring the power supply and load to be integrated within the same silicon die. SUMMARY

[0006] According to an embodiment of a switching voltage converter module, the module is configured to conduct current in a vertical direction. The module comprises a substrate, an input terminal, an output terminal, one or more power switches, and an inductor. The substrate has a first main surface and a second main surface opposite to each other. The input terminal is located at the first main surface and is configured for connection to a power source. The output terminal is located at the second main surface and is configured to be connected to a power sink (load). The one or more power switches and the inductor are embedded in the substrate between the first main surface and the second main surface, and the inductor is coupled to the one or more power switches. The inductor can be a single (uncoupled) inductor or a coupled inductor.

[0007] According to an embodiment of a processor system, the processor system comprises a processor substrate, a processor attached to the processor substrate, and a switching voltage converter module arranged within the processor substrate. The switching voltage converter module comprises a converter substrate, a converter input terminal, a converter output terminal, one or more power switches, and an inductor. The converter substrate has a first main surface and a second main surface opposite to each other. The converter input terminal is located at the first main surface and is configured for connection to a power source. The converter output terminal is located at the second main surface and is connected to an input power terminal of the processor substrate. The one or more power switches and the inductor are embedded in the converter substrate between the first main surface and the second main surface, and the inductor is coupled to the one or more power switches.

[0008] According to an embodiment of a circuit board system, the system comprises a circuit board having a first surface, a power source, and a processor system. The processor system comprises a processor substrate electrically connected to the first surface, a processor attached to the processor substrate, and a switching voltage converter module arranged within the processor substrate. The switching voltage converter module comprises a converter substrate, a converter input terminal, a converter output terminal, one or more power switches, and an inductor. The converter substrate has a first main surface and a second main surface opposite to each other. The converter input terminal is located at the first main surface and is configured for connection to the power source via a power terminal of the circuit board. The converter output terminal is located at the second main surface and is connected to an input power terminal of the processor substrate. The one or more power switches and the inductor are embedded in the converter substrate between the first main surface and the second main surface, and the inductor is coupled to the one or more power switches.

[0009] Those skilled in the art will realize, upon reading the following detailed description and upon viewing the appended drawings, further features and advantages of the present application. BRIEF DESCRIPTION OF DRAWINGS

[0010] The elements of the drawings are not necessarily to scale relative to each other. Like reference numbers refer to corresponding parts throughout. The individual embodiments illustrated are not mutually exclusive, except where otherwise explained. Embodiments are depicted in the drawings and described in detail in the following description.

[0011] Figure 1 A schematic diagram of a voltage converter module and associated circuitry is illustrated.

[0012] Figure 2 Different views of a voltage converter module within a package substrate are illustrated. Figure 1 and a circuit board and microprocessor attached to the package substrate.

[0013] Figure 3A , Figure 3B and Figure 3C Different views of a voltage converter module within a package substrate are illustrated.

[0014] Figure 4A and Figure 4B A schematic diagram of a two-phase voltage converter module including coupled inductors is illustrated.

[0015] Figure 5A , Figure 5B , Figure 5C , Figure 5D and Figure 5E Different views of a voltage converter module within a package substrate are illustrated. Figure 4A and Figure 4B Different views of a voltage converter module within a package substrate are illustrated. DETAILED DESCRIPTION

[0016] Placing a voltage converter next to a microprocessor or similar digital-intensive integrated circuit (IC) on a circuit board can result in significant conduction losses due to lateral current conduction through the circuit board. Integrating a voltage converter with a microprocessor in the same silicon die presents some problems that make it difficult to solve for many applications. Specifically, any defects within the voltage converter portion of the die can render the integrated microprocessor / voltage converter unusable, reducing the yield of the relatively expensive microprocessor. It is generally preferred to have the voltage converter as a separate module that can be tested and trimmed so that a known good voltage converter is available for subsequent pairing with a (relatively expensive) microprocessor die or similar digital device.

[0017] One option is to integrate the voltage converter and the microprocessor on the same package substrate (but not in the same silicon die), which is then mounted to a circuit board. This option has the advantage that high voltage power, which is relatively low current, is supplied to the package substrate. Because the current is low, fewer pins are needed on the package substrate to supply power compared to a non-integrated voltage converter. High current (low voltage) power is constrained to the package substrate. In one version of this implementation, the power switches and associated drivers of the voltage converter can be integrated within the package substrate. The inductors and capacitors of the voltage converter (typically a buck converter) are mounted on the top of the substrate, e.g., next to the microprocessor. While this implementation offers the modular advantage relative to integrating the microprocessor and voltage converter in the same silicon die, and offers an improvement in power loss relative to a non-integrated solution, the solution has several drawbacks. First, placing the inductors and capacitors next to the microprocessor requires a moderate lateral conduction path to still exist for the large current, which results in undesirable power loss and reduced efficiency. Second, placing the inductors on the top of the substrate means that the switching nodes of the buck converter, etc., are external to the substrate, generating undesirable electromagnetic interference within the system.

[0018] The embodiments described herein address these problems and reduce power loss and interference while maintaining the modularity of the voltage converter. This is achieved in part by embedding the inductor(s) of the voltage converter within a voltage converter inlay that can be placed in the package substrate. The voltage converter can include a single inductor, or can include coupled inductors that support, for example, a two-phase buck converter. Still further, the voltage converter can include multiple single inductors or multiple coupled inductors. By embedding one or more inductors in the voltage converter inlay, the switching nodes (e.g., the nodes that connect the high-side power transistor to the low-side power transistor and to the inductor) are not routed to the external surface of the package substrate. Thus, high frequency noise associated with the switching nodes can be better suppressed. Additionally, in some embodiments, the input and output capacitors of the voltage converter can be integrated within the inlay, rather than mounted on the package substrate. Such embodiments further reduce lateral current flow and associated power loss. The voltage converter inlay can be placed within a cavity of the package substrate, and can provide shielding such that high frequency interference radiating from the inlay or package substrate is minimized.

[0019] The invention is described below using several embodiments, which should not be considered limiting. Embodiments of a switching voltage converter module or inlay are described, as well as processor systems and circuit board systems incorporating the switching voltage converter module. In an exemplary processor system, a microprocessor die is attached to a package substrate, which provides connections between the microprocessor and a circuit board. The package substrate includes a cavity between the microprocessor die and the circuit board, in which a switching voltage converter module can be disposed. The switching voltage converter module is configured to supply current vertically from the circuit board to the microprocessor. High voltage, low current power can be provided from the circuit board to the switching voltage converter module. In a typical implementation, the switching voltage converter module steps down the supplied voltage in order to supply low voltage, high current power to the microprocessor. Current flows vertically through the switching voltage converter module from an input terminal located on a first surface facing the circuit board to an output terminal located on a second surface facing the microprocessor.

[0020] For ease of illustration, the invention is described below using examples that include a microprocessor or central processing unit (CPU). It should be understood that similar systems can alternatively or additionally include a graphics processing unit (GPU), an application specific integrated circuit (ASIC), an artificial intelligence (AI) accelerator, or other host digital circuitry, and that the voltage converter modules described herein can be used in such similar systems.

[0021] Figure 1 And Figure 2 A system is illustrated that includes a voltage converter module 110 for powering a load 160 such as a microprocessor or similar power sink. Figure 1 A circuit schematic 100 of such a system is illustrated, while Figure 2 The physical arrangement of components within such a system 200 is illustrated.

[0022] Figure 1 The circuit 100 includes a voltage converter module 110, a load 160, and a controller / driver circuit 140. The voltage converter module 110 is supplied with an input voltage V IN . An input capacitor C IN The input voltage V INFiltering is performed. As illustrated, the voltage converter module 110 is a buck converter that includes a high-side switch Ql, a low-side switch Q2, and an inductor LI. The high-side switch Ql is coupled between the input terminal 101 and a switch node SW, while the low-side switch Q2 is coupled between the switch node SW and ground. The illustrated switches Ql, Q2 are n-channel MOSFETs, but it is understood that other switch types can be used, such as p-channel MOSFETs, JFETs, insulated-gate bipolar transistors (IGBTs), bipolar junction transistors (BJTs), and high electron mobility transistors (HEMTs). Regardless of the switch type, the power switches Ql, Q2 can be provided on separate dies, or can be monolithically integrated in the same semiconductor die. The energy storage inductor LI couples the switch node SW to the output V OUT and an associated filter capacitor C OUT . The output voltage V OUT is provided to the load 160 via a load current I LOAD to power the load 160 (e.g., a microprocessor).

[0023] The controller 142 generates switching control signals for the switches Ql, Q2 in order to maintain the output voltage V OUT at a desired (e.g., target) value. The switching control signals are provided to the switches Ql, Q2 via drivers 144, 146. The output voltage V OUT is fed back to the controller 142 so that the controller 142 can implement closed-loop control. For example, the controller 142 can include a proportional-integral-derivative (PID) controller. Because control techniques including closed-loop and open-loop control, as well as transistor drivers, are well known in the art, they are not further described herein.

[0024] The controller 142 and the load 160 can coordinate power supply. For example, the load 160 can inform the controller 142, e.g., via the illustrated "load position" signal, that the load 160 is changing to a different power mode, e.g., a sleep mode or a high-power consumption mode. The controller 142 can adjust its power output predictively according to the load position signal, rather than reactively to the changed load. For example, the load 160 can provide an adaptive voltage position (AVP) signal to the controller 142 so that the controller 142 increases the supplied power in anticipation of an increased processor load. The co-location of the controller 142 and the load 160 in / on the same package substrate makes such predictive load positioning more feasible. When the load 160 is a microprocessor and the voltage converter controller is integrated within the microprocessor, as described with respect to Figure 4B , such predictive load positioning becomes even more easily implemented.

[0025] Figure 2A cross-sectional view of a circuit board system 200 is illustrated, the circuit board system 200 including an arrangement of components of the circuit 100. The system 200 includes a circuit board 180 and a package substrate 190. The circuit board 180 has a first surface 182 onto which the package substrate 190 is mounted. A power source (not shown for ease of illustration) provides power to the circuit board 180, which in turn provides input power to the package substrate 190 via one terminal (multiple terminals) 101 and one or more ground terminals located on a first surface 192 of the package substrate 190.

[0026] A load 160 is attached at a second surface 194 of the package substrate 190. The load 160 is a microprocessor die as illustrated, but it should be understood that other processing circuitry including, for example, a GPU, an ASIC, an AI accelerator, or a digital signal processor (DSP) can be used in place of the microprocessor. The load 160 has multiple signal terminals and one or more power terminals that are coupled to corresponding terminals on the package substrate 190. (These terminals are not shown for ease of illustration.)

[0027] The package substrate 190 has additional terminals on its first surface 192 for electrical connection to the circuit board 180. These terminals can be, for example, balls of a ball grid array (BGA) or through-hole pins. The terminals can be attached (e.g., soldered) directly to the circuit board 180 using, for example, through-holes or BGA pads on the circuit board 180. Alternatively, a socket (not shown for ease of illustration) can be used to connect the package substrate 190 to the circuit board 180, i.e., the socket can be soldered to the circuit board 180 and the package substrate 190 can be inserted into the socket. The use of a socket enables easy replacement of the microprocessor 160 and associated components attached to the package substrate 190. This is beneficial if a fault is discovered after the microprocessor 160 or associated components are mounted to the circuit board 180 or if it is desired to upgrade the microprocessor 160 at some future date after the initial population of the circuit board 180. The inclusion of the voltage converter (e.g., the buck converter 110) enables power to be delivered to the socket using a high voltage and low current. The low current reduces power dissipation through the pins of the socket and reduces the number of socket pins required, making the use of a socket more feasible.

[0028] The buck converter 110 is embedded within the package substrate 190. Specifically, the high-side switch Ql, the low-side switch Q2, and the inductor LI are embedded in a cavity between the first surface 192 and the second surface 194 of the package substrate 190. The input terminal 101 is connected to the high-side switch Ql, while the ground terminal (GND) is connected to the low-side switch Q2. The input terminal (or terminals) 101 and the ground terminal (or terminals) GND are located at the first surface 192 of the package substrate 190. The input capacitor C INand an output capacitor C OUT mounted on a second surface 194 of the package substrate 190.

[0029] The voltage converter controller / driver circuit 140 can be included within the package substrate 190, such that the controller 142 can readily communicate with the load 160 for load positioning, and such that the drivers 144, 146 are reasonably positioned proximate to the switches Ql, Q2. While not explicitly shown in the package substrate 190, the voltage converter controller / driver circuit 140 can be located in front of or behind the buck converter 110, and in Figure 2 visible in the cross-sectional view. Alternatively, the voltage controller / driver circuit 140 can be located to the side of the buck converter 110, for example, under the illustrated microprocessor die 160. In another alternative, the drivers 144, 146 can be monolithically integrated in the same semiconductor die as the switches Ql, Q2, such that the driver 144 is integrated in the same die as the high-side switch Ql, and the driver 146 is monolithically integrated in the same die as the low-side switch Q2. In another alternative, the drivers 144, 146 can be integrated in the same semiconductor die, while the power switches Ql, Q2 are integrated in another semiconductor die. In yet another alternative, the drivers 144, 146 and the power switches Ql, Q2 can be monolithically integrated in the same die.

[0030] Figure 3A 、 Figure 3B and Figure 3C Three views of a processor system 300 are illustrated, including a microprocessor die (load) 360, a package substrate 390, and a voltage converter module 310. Figure 3A A schematic diagram showing the top and side of the processor system 300 is provided. Figure 3B A plan view of a first major surface 392 of the processor system 300 is provided. Figure 3C A cross-sectional view of the processor system 300 is provided.

[0031] As shown in Figure 3A The package substrate 390 has a first major surface 392, also referred to as a bottom surface, which is configured for mounting to a circuit board, socket, or the like. A second major surface 394, also referred to as a top surface, is on an opposite side of the package substrate 390. The microprocessor 360, for example a silicon die including digital circuitry, is mounted to the top surface 394, for example using a ball grid array or similar terminals for conveying digital signals, power, and the like. A plurality of discrete components 399, for example pull-up resistors, pull-down resistors, decoupling capacitors, are also mounted on the top surface 394 of the package substrate.

[0032] Figure 3BA plan view of the bottom surface 392 of the package substrate 390 is illustrated. The package substrate 390 has a cavity 396 located near its center. This cavity 396 extends from the bottom surface 392 into the body of the package substrate 390. The voltage converter module 310 is mounted within the cavity 396. As illustrated, a plurality of terminals 398 (e.g., balls or pins of a BGA) surround the cavity 396.

[0033] Figure 3C A cross-sectional view of the processor system 300 including the components described above is illustrated. It can be seen that the terminals 398 extend from the bottom surface 392 of the package substrate 390 and are configured for electrical connection to a circuit board (not shown for ease of illustration). In addition to the terminals 398 of the package substrate 390, the voltage converter module 310 also has one or more terminals 398VR, e.g., for inputting power from a power source (also not shown for ease of illustration) to the voltage converter module 310 via the circuit board (also not shown for ease of illustration). This arrangement of voltage converter terminals 398VR allows for the application of a locally higher voltage in the center portion of another (e.g., digital signal) terminal 398. For example, a digital signal transmitted through the terminals 398 can have a relatively low current at a low voltage of 1 V, while the power pins 398VR can include power pins for transmission at a much higher current (e.g., 3 V). By confining the power terminals 398VR to the center portion of the substrate surface 392, the power terminals 398VR can be prevented from interfering with the digital signal. Further still and as shown, the power terminals 398VR preferably include a ground terminal on the periphery and a terminal on the center for inputting a power source (e.g., V Figure 5A IN ) such that the signal terminals 398 are physically separated and somewhat shielded from noise that can be present on the terminals inputting the power source.

[0034] Figures 4A-4B and Figures 5A-5E A circuit schematic and physical arrangement of a processor system such as Figures 3A-3C is illustrated, but with particular emphasis on the voltage converter module portion of such a processor system. Figure 4A and Figures 5A-5E The voltage converter module portion of Figures 3A-3C may be incorporated as a voltage converter tile (VR) 310 in the processor system 300 of

[0035] Figure 4A A circuit schematic 400 for a voltage converter module including a coupled inductor 420 is illustrated. The circuit 400 includes two phases of a buck converter. (This can be equivalently viewed as two single-phase buck converters.) Each of these phases is in a similar configuration as Figure 1 ​The voltage converter 110 is configured in much the same way as the buck converter 110 of FIG. 1. Specifically, phase A includes a first switch Q1A (phase A high-side switch), a second switch Q2A (phase A low-side switch), and a first winding LA. The first and second switches are connected at a phase A switch node SWA. Phase B includes a third switch Q1B (phase B high-side switch), a fourth switch Q2B (phase B low-side switch), and a second winding LB. The third and fourth switches are connected at a phase B switch node SWB.

[0036] The input terminal 401 provides an input voltage VIN for supplying power to both phase A and phase B. Input capacitors C1A, C1B filter the input voltage VIN and are preferably physically located near the high-side switches Q1A, Q1B, respectively. The output terminal 402 provides an output voltage VOUT for supplying power to a load such as a microprocessor. The output terminal 402 is provided with a current IA from the first winding LA and a current IB from the second winding LB. Output capacitors C2A, C2B filter the output voltage VOUT and are preferably physically located near the output terminal 402.

[0037] The windings LA, LB are part of a coupled inductor 420 and are wound around a common core 422 in opposite configurations. Using a coupled inductor reduces the volume of core material such as ferrite, as compared to two non-coupled inductors, because the direct current (DC) portions of the magnetic fields from both sides cancel each other out, thereby providing high system density. Reducing the size of the coupled inductor makes it more feasible to include it within a voltage converter dielet of a package substrate, as described in further detail below.

[0038] The voltage converter controller 442 generates control signals for driving the switches Q1A, Q2A, Q1B, Q2B via drivers 444a, 446a, 444b, 446b. For example, these signals are generated using closed loop control, in which the output voltage VOUT is regulated to a desired target voltage. The output voltage VOUT is input to the voltage converter controller 442 so that it can be sensed by the closed loop controller. The phase A and phase B signals are preferably generated with a phase offset of, for example, 180°, so that the currents IA, IB have a phase offset and the ripple of the total load current provided at the output terminal 402 is minimized. Because closed loop control and voltage regulation are well known in the art, no further details are provided regarding these topics.

[0039] The output terminal 402 is electrically coupled to the microprocessor 460 and supplies an output voltage VOUT to the microprocessor 460. The microprocessor 460 can have several modes of operation, each with different power requirements. The microprocessor 460 can provide a "load position" signal to the voltage converter controller 442, which provides an indication of an upcoming power demand. For example, a microprocessor exiting a sleep mode can notify the voltage converter controller 442 of its upcoming state so that the voltage converter controller can increase the supplied current in preparation for the high power state, rather than reacting to the higher current consumption and generating a voltage droop during this time. The voltage converter controller / driver circuit 440 can be located within the package substrate, and if so, is preferably located within the same voltage converter die as the two-phase buck converter. This minimizes trace length and noise associated with the switching control signals PWM_Q1A, PWM_Q1B, PWM_Q2A, PWM_Q2B, which are typically pulse width modulated (PWM), and provides a fast path for exchanging the load position signal between the microprocessor 460 and the voltage converter controller 442.

[0040] Figure 4B A variation of the controller portion of the circuit 400 of Figure 4A is illustrated. In this variation, the voltage converter controller 442 is implemented within the microprocessor 460B, such that the microprocessor 460B generates the switching control signals for the switches Q1A, Q2A, Q1B, Q2B. For example, a closed loop control technique can generate the switching control signals based on a sensed output voltage VOUT, and / or a feed forward control technique can use a load position signal generated by a power mode controller 462 within the microprocessor 460B. This split provides an advantage with respect to the speed at which the voltage converter can adapt to new power modes, which can be preferred in some applications. The drivers 444a, 446a, 444b, 446b can also be integrated within the microprocessor die 460B, but more typically, the drivers 444a, 446a, 444b, 446b are preferably implemented within the voltage converter module / die, as the digital silicon die 460B can not be suitable for implementing the relatively high current analog transistor drivers 444a, 446a, 444b, 446b.

[0041] Figure 5A A cross-sectional view of a processor system 500 is illustrated, which includes a voltage converter module 410 that includes a coupled inductor 420, as described in the circuit 400 of FIG. 4. Figures 5B-5EFIG. 5 is a cross-sectional view and subsequent views showing the detailed physical arrangement of power flow related components of the two-phase buck converter of FIG. 4. For ease of illustration, the voltage converter controller / driver circuit 440 of FIG. 4 is not shown, but it is understood that these circuits can be located within the voltage converter module 500 of FIG. 5, for example, in unshown views, or that the voltage converter controller 442 can be integrated within the microprocessor die.

[0042] The processor system 500 includes a microprocessor die 460, a package substrate 490, and a voltage converter module 410, which can be referred to as an inlay. Current flow through the voltage converter module 410 is largely vertical (i.e., along the thickness direction of the voltage converter module 410 between the top major surface 412 and the bottom major surface 414), and unnecessary lateral current flow is minimized. In particular, note that the switches (transistors) Q1A, Q2A, Q1B, Q2B are vertical power transistors, such as vertical power MOSFETs. (In some applications, other switch types including JFETs, IGBTs, BJTs, and HEMTs can be preferred). As illustrated, the switches Q1A, Q2A, Q1B, Q2B are located in separate dies, but in other embodiments, some or all of the switches can be monolithically integrated in the same semiconductor die. Non-vertical power transistors can also be used, for example, transistors that provide greater lateral current flow with the transistor load terminal located on the same surface of the transistor; and non-vertical power transistors can be more feasible when high-side and low-side power switches are monolithically integrated in the same die.

[0043] The switch nodes (e.g., SWA, SWB) are contained within the voltage converter inlay 410 that is located in a cavity of the package substrate 490, such that the switch nodes SWA, SWB and the microprocessor die 460 are together largely shielded from the metallization of the output terminal 402 and ground (PGND). Thus, compared to other solutions including Figure 2 The system provides the advantage of reduced electromagnetic interference (EMI) compared to other solutions, including the solution of FIG. 1 in which the switch nodes are placed outside of the voltage converter inlay and package substrate.

[0044] High-side MOSFETs (switches) Q1A, Q1B have their drains facing down towards an input terminal 401 at a first major surface (bottom) 412 of the voltage converter die 410 and supply an input voltage VIN. Current flows vertically through these MOSFETs Q1A, Q1B to respective sources. The sources of the high-side MOSFETs Q1A, Q1B are coupled to the drains of low-side MOSFETs Q2A, Q2B at switch nodes SWA, SWB, respectively. As illustrated, the sources of the low-side MOSFETs Q2A, Q2B are coupled to a ground metallization that is connected through to a power ground terminal (PGND) at the bottom surface 412.

[0045] The phase A input capacitor C1A is preferably located near the phase A high-side MOSFET Q1A and the phase A low-side MOSFET Q2A, while the phase B input capacitor C1B is preferably located near the phase B high-side MOSFET Q1B and the low-side MOSFET Q2B. This reduces parasitic inductance loops, thus reducing ringing at the switch nodes SWA, SWB. As illustrated, both terminals of each of the input capacitors C1A, C1B are on the same side to reduce parasitic loops. These capacitors C1A, C1B can be implemented as, for example, silicon trench capacitors or ceramic capacitors.

[0046] The phase A switch node SWA is connected to a phase A winding LA of a coupled inductor 420 on a first side of the coupled inductor. The other end of the winding LA is on the opposite side of the coupled inductor at a phase A output voltage node VOUT A. Phase A current IA flows from the switch node SWA through the winding LA and to the output voltage node VOUT A. The phase B components are configured in a similar manner, but in a mirror arrangement to the corresponding phase A components. Phase B current IB flows from the switch node SWB through the winding LB and to the output voltage node VOUT B. The windings LA, LB are wound around a common core 422, which is typically a magnetic core. By using a common core for both windings LA, LB, the required volume of the coupled inductor 420 is reduced relative to other inductors (e.g., two inductors with different and separate cores). The output voltage connections VOUT A, VOUT B of the coupled inductor 420 are merged on a top level (surface) 414 of the voltage converter die 410 to form an output terminal 402 that provides a relatively low DC output voltage VOUT to the microprocessor die 460. The output voltage VOUT and the power ground PGND can be routed vertically to the microprocessor 460, which is placed directly above the voltage converter die 410.

[0047] Preferably, output capacitors are also integrated within the voltage converter die 410. As Figure 5AAs shown, output capacitors C2A, C2B are positioned adjacent to phase A output voltage node VOUT A and phase B output voltage node VOUT B, respectively. This integration and positioning of output capacitors C2A, C2B reduces EMI and output voltage ripple. The illustrated output capacitors C2A, C2B each have terminals on opposite sides, and can be implemented as silicon trench capacitors or ceramic capacitors within the substrate of voltage converter die 410.

[0048] Figure 5B A plan view of top surface 414 of voltage converter die 410 is illustrated. Top surface 414 includes metallization for output terminals 402 and metallization 403 for power supply ground PGND. These metallizations 402, 403 are configured to be connected to microprocessor 160, for example, using vias (not shown for ease of illustration) within packaging substrate 490. For ease of reference, switch nodes SWA, SWB and output capacitors C2A, C2B are shown in dashed boxes, but should be understood to be located in the lower layer of voltage converter substrate 450, and connected through to top surface 414 using vias as shown in the cross-sectional view of FIG. 4B. Figure 5A Metallizations 402, 403 substantially cover all of the following: coupled inductor 420, switch nodes SWA, SWB, and output voltage connections VOUT A, VOUT B connected to output capacitors C2A, C2B. Thus, these metallizations 402, 403 form a shield between the high frequency and high current signals of voltage converter die 410 and other parts of the system.

[0049] Figure 5C A cross-sectional view of coupled inductor 420 is illustrated, which includes metallization (e.g., tabs) 424a, 426a, 424b, 426b for its terminals. Coupled inductor 420 is placed within a cavity of substrate 450, where the cavity cuts through interconnect layer 416 of voltage converter die 410. Phase A switch node SWA (terminal 424a) is connected to a first winding LA of coupled inductor 420, such that current flows from switch node SWA to phase A output voltage connection VOUT A (terminal 426a). Likewise, phase B switch node SWB is connected to a second winding LB of coupled inductor 420, such that current flows from switch node SWB (terminal 424b) to phase B output voltage connection VOUT B (terminal 426b).

[0050] Figure 5DA view through the interconnect layer 416 is illustrated and shows connections external to the coupled inductor 420. This layer 416 includes metallization corresponding to phase A switch node SWA that is electrically connected to the source of high-side switch Q1A, the drain of low-side switch Q2A, and the input terminal 424a of first winding LA. Similar metallization for phase B switch node SWB is also included that is electrically connected to the source of high-side switch Q1B, the drain of low-side switch Q2B, and the input terminal 424b of second winding LB. For ease of reference, switches Q1A, Q2A, Q1B, Q2B are shown in dashed boxes, but should be understood to be located directly below the interconnect layer 416 as Figure 5A In one embodiment, a cavity 530 is formed in the inlay substrate 450 and extends through the interconnect layer 416. The cavity 530 is configured to receive the coupled inductor 420. The coupled inductor 420 can be placed in the cavity 530 prior to forming the top surface and interconnect layer 418 when fabricating the layers of the voltage converter inlay 410. The leads 424a, 426a, 424b, 426b corresponding to the windings LA, LB of the inductor 420 are coupled to the switch nodes SWA, SWB and the output voltage connections VOUT_A, VOUT_B. Alternatively, the coupled inductor 420 can be fabricated directly within the inlay substrate 450.

[0051] Figure 5E A cross-sectional view of the interconnect layer 418 is illustrated. The VIN metallization 418vin forms an S-shape through the layer 418, with the center portion of this metallization 418vin connected to the input terminal 401 of the bottom surface 412, for example, using a via as Figure 5A The metallization 418vin is connected to the drains of high-side switches Q1A, Q1B. The remaining area of the interconnect layer 418 includes ground metallization 418gnd. These metallization 418gnd are connected to the sources of low-side switches Q2A, Q2B. Input capacitors C1A, C2A are coupled across the input voltage metallization 418vin and the ground metallization 418gnd directly below the interconnect layer 418. The ground metallization 418gnd is connected to the output capacitors C2A, C2B, for example, using a via. As shown in dashed boxes, the switches Q1A, Q2A, Q1B, Q2B and the output capacitors C2A, C2B are not within the interconnect layer 418, but are above it. Likewise, the input capacitors C1A, C1B and the input voltage terminal 401 are not within the interconnect layer 418, but are below it.

[0052] While the disclosure is not limited in this regard, the following numbered examples illustrate one or more aspects of the disclosure.

[0053] Example 1. A switched voltage converter module configured to conduct current in a vertical direction. The module includes a substrate, an input terminal, an output terminal, one or more power switches, and an inductor. The substrate has a first major surface and a second major surface opposite the first major surface. The input terminal is at the first major surface and is configured to be connected to a load. The output terminal is at the second major surface and is configured to be connected to a power sink. The one or more power switches and the inductor are embedded in the substrate between the first major surface and the second major surface, and the inductor is coupled to the one or more power switches.

[0054] Example 2. The switched voltage converter module of example 1, wherein the inductor includes a coupled inductor, the coupled inductor including a first winding and a second winding. The first winding is wound on a common core and has a first inductor input coupled to a first switch node and a first inductor output. The second winding is also wound on the common core and has a second inductor input coupled to a second switch node and a second inductor output.

[0055] Example 3. The switched voltage converter module of example 2, including a first phase and a second phase. The first phase includes the first winding, a first power switch coupled between the input terminal and the first switch node, and a second power switch coupled between the first switch node and a reference. The second phase includes the second winding, a third power switch coupled between the input terminal and the second switch node, and a fourth power switch coupled between the second switch node and the reference. The one or more power switches include the first power switch, the second power switch, the third power switch, and the fourth power switch.

[0056] Example 4. The switched voltage converter of example 3, wherein each of the first phase and the second phase is a buck converter configured to convert an input voltage at the input terminal to an output voltage at the output terminal. The first inductor output and the second inductor output are coupled to the output terminal.

[0057] Example 5. The switched voltage converter module of example 1, wherein a metallization of the output terminal in combination with a metallization of one or more reference terminals or the output terminal includes a metal shield that completely covers a core of the inductor.

[0058] Example 6. The switched voltage converter module of example 5, wherein the one or more power switches and switch nodes coupled to the one or more power switches are covered by a metallization of the output terminal or by a metallization of the output terminal in combination with a metallization of one or more reference terminals.

[0059] Example 7. The switching voltage converter module of example 6, wherein the output terminal comprises an inner portion of the second major surface, and an outer portion of the second major surface comprises the one or more reference terminals.

[0060] Example 8. The switching voltage converter module of example 7, wherein the one or more reference terminals of the second major surface comprise a continuous metallization around a metallization of the output terminal.

[0061] Example 9. The switching voltage converter module of example 1, wherein the inductor is placed within a cavity of the switching voltage converter module.

[0062] Example 10. The switching voltage converter module of example 1, wherein the one or more power switches are vertical power metal-oxide-semiconductor field-effect transistors (MOSFETs).

[0063] Example 11. The switching voltage converter module of example 1, wherein at least two of the one or more power switches are monolithically integrated in the same semiconductor die.

[0064] Example 12. The switching voltage converter module of example 1, wherein at least a first power switch of the one or more power switches and a first switch driver configured to drive the first power switch are monolithically integrated in the same semiconductor die.

[0065] Example 13. The switching voltage converter module of example 1, further comprising an input capacitor and an output capacitor. The input capacitor is coupled between the input terminal and the reference and is embedded in the substrate between the first major surface and the second major surface. The output capacitor is coupled between the output terminal and the reference and is embedded in the substrate between the first major surface and the second major surface.

[0066] Example 14. The switching voltage converter module of example 13, wherein the output capacitor is a vertical capacitor having a first terminal proximate to the first horizontal surface and a second terminal proximate to the second horizontal surface.

[0067] Example 15. The switching voltage converter module of example 13, wherein the input capacitor and the output capacitor are silicon capacitors.

[0068] Example 16. The switching voltage converter module of example 13, wherein the input capacitor is a silicon capacitor monolithically integrated in the same die as at least one of the one or more power switches.

[0069] Example 17. The switching voltage converter module of example 16, wherein the output capacitor is a silicon capacitor monolithically integrated in the same die.

[0070] Example 18. A processor system comprising: a processor substrate; a processor attached to the processor substrate; and a switched voltage converter module arranged within the processor substrate. The switched voltage converter module comprises a converter substrate, a converter input terminal, a converter output terminal, one or more power switches, and an inductor. The converter substrate has a first major surface and a second major surface opposite to each other. The converter input terminal is located at the first major surface and is configured to be connected to a power source. The converter output terminal is located at the second major surface and is connected to an input power terminal of the processor substrate. The one or more power switches and the inductor are embedded in the converter substrate between the first major surface and the second major surface, and the inductor is coupled to the one or more power switches.

[0071] Example 19. A circuit board system comprising a circuit board having a first surface, a power source, and a processor system. The processor system comprises: a processor substrate electrically connected to the first surface; a processor attached to the processor substrate; and a switched voltage converter module arranged within the processor substrate. The switched voltage converter module comprises a converter substrate, a converter input terminal, a converter output terminal, one or more power switches, and an inductor. The converter substrate has a first major surface and a second major surface opposite to each other. The converter input terminal is located at the first major surface and is configured to be connected to the power source via a power terminal of the circuit board. The converter output terminal is located at the second major surface and is connected to an input power terminal of the processor substrate. The one or more power switches and the inductor are embedded in the converter substrate between the first major surface and the second major surface, and the inductor is coupled to the one or more power switches.

[0072] Example 20. The circuit board system according to example 19, further comprising a socket attached to the first surface and configured to provide electrical connection to the processor substrate of the processor system.

[0073] As used herein, the terms “have,” “having,” “contain,” “containing,” “include,” “including,” and the like are open-ended terms that indicate the presence of the stated element or elements but do not preclude the presence of additional elements or features. The articles “a,” “an,” and “the” are intended to include the plural as well as the singular, unless the context clearly indicates otherwise.

[0074] It is to be understood that the features of the various embodiments described herein can be combined with each other, unless specifically noted otherwise.

[0075] While certain embodiments have been shown and described above, it is to be understood that the application can be practiced with the use of alternative and / or equivalent embodiments. The present application is not limited to the embodiments described above, but rather the scope of the present application is to be accorded the full scope permissible by the law.

Claims

1. A switching voltage converter module configured to conduct current in the vertical direction, the switching voltage converter module comprising: The substrate has a first main surface and a second main surface opposite to the first main surface; An input terminal is located on the first main surface and is configured to be connected to a power source; An output terminal is located on the second main surface and is configured to be connected to a load; One or more power switches are embedded in the substrate between the first main surface and the second main surface; as well as An inductor, embedded in the substrate, and coupled to the one or more power switches. The metallization of the output terminal is combined with the metallization of one or more reference terminals, or the output terminal includes a metal shield that completely covers the core of the inductor, and the one or more power switches and the switching nodes coupled to the one or more power switches are covered by the metallization of the output terminal or by a combination of the metallization of the output terminal and the metallization of the one or more reference terminals.

2. The switching voltage converter module according to claim 1, wherein the inductor includes a coupling inductor, the coupling inductor comprising: A first winding, on a common core, has a first inductor input and a first inductor output, the first inductor input being coupled to a first switching node; as well as A second winding is located on the common core and has a second inductor input and a second inductor output, the second inductor input being coupled to a second switching node.

3. The switching voltage converter module according to claim 2, comprising: The first phase includes the first winding, a first power switch coupled between the input terminal and the first switching node, and a second power switch coupled between the first switching node and a reference. as well as The second phase includes the second winding, a third power switch coupled between the input terminal and the second switching node, and a fourth power switch coupled between the second switching node and the reference. The one or more power switches include the first power switch, the second power switch, the third power switch, and the fourth power switch.

4. The switching voltage converter module of claim 3, wherein each of the first phase and the second phase is a buck converter configured to convert an input voltage at the input terminal to an output voltage at the output terminal, and wherein the first inductor output and the second inductor output are coupled to the output terminal.

5. The switching voltage converter module of claim 1, wherein the output terminal includes an inner portion of the second main surface, and the outer portion of the second main surface includes the one or more reference terminals.

6. The switching voltage converter module of claim 5, wherein the one or more reference terminals of the second main surface include a continuous metallization surrounding the output terminal.

7. The switching voltage converter module according to claim 1, wherein the inductor is placed inside the cavity of the switching voltage converter module.

8. The switching voltage converter module of claim 1, wherein the one or more power switches are vertical power metal-oxide-semiconductor field-effect transistors (MOSFETs).

9. The switching voltage converter module according to claim 1, wherein at least two of the one or more power switches are monolithically integrated on the same semiconductor die.

10. The switching voltage converter module of claim 1, wherein at least a first power switch of the one or more power switches and a first switch driver configured to drive the first power switch are monolithically integrated in the same semiconductor die.

11. The switching voltage converter module according to claim 1, further comprising: An input capacitor is coupled between the input terminal and the reference, and is embedded in the substrate between the first main surface and the second main surface; as well as An output capacitor is coupled between the output terminal and the reference, and is embedded in the substrate between the first main surface and the second main surface.

12. The switching voltage converter module of claim 11, wherein the output capacitor is a vertical capacitor having a first terminal near the first main surface and a second terminal near the second main surface.

13. The switching voltage converter module of claim 11, wherein the input capacitor and the output capacitor are silicon capacitors.

14. The switching voltage converter module of claim 11, wherein the input capacitor is a silicon capacitor monolithically integrated on the same die as at least one of the one or more power switches.

15. The switching voltage converter module of claim 14, wherein the output capacitor is a silicon capacitor monolithically integrated with the same die.

16. A processor system, comprising: Processor substrate; The processor is attached to the processor substrate; as well as A switching voltage converter module, disposed within the processor substrate, includes: A converter substrate having a first main surface and a second main surface opposite to the first main surface; The converter input terminal is located on the first main surface and is configured to be connected to a power source; The converter output terminal is located on the second main surface and is connected to the input power terminal of the processor substrate; One or more power switches are embedded in the converter substrate between the first main surface and the second main surface; and An inductor, embedded in the converter substrate, and coupled to the one or more power switches, The combination of the metallization of the converter output terminal and the metallization of one or more reference terminals, or the converter output terminal including a metal shield that completely covers the core of the inductor, and the one or more power switches and the switching nodes coupled to the one or more power switches are covered by the metallization of the converter output terminal or by a combination of the metallization of the converter output terminal and the metallization of the one or more reference terminals.

17. A circuit board system, comprising: A circuit board having a first surface; Power source; as well as Processor system, including: The processor substrate is electrically connected to the first surface; Processor, attached to the processor substrate; and A switching voltage converter module, disposed within the processor substrate, includes: A converter substrate having a first main surface and a second main surface opposite to the first main surface; The converter input terminal is located on the first main surface and is configured to be connected to the power source via the power terminals of the circuit board; The converter output terminal is located on the second main surface and is connected to the input power terminal of the processor substrate; One or more power switches are embedded in the converter substrate between the first main surface and the second main surface; and An inductor, embedded in the converter substrate, and coupled to the one or more power switches, The combination of the metallization of the converter output terminal and the metallization of one or more reference terminals, or the converter output terminal including a metal shield that completely covers the core of the inductor, and the one or more power switches and the switching nodes coupled to the one or more power switches are covered by the metallization of the converter output terminal or by a combination of the metallization of the converter output terminal and the metallization of the one or more reference terminals.

18. The circuit board system of claim 17, further comprising: A socket is attached to the first surface and configured to provide an electrical connection to the processor substrate of the processor system.

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