DC Power II: Power Modules
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Power modules produce smaller, faster, and more reliable energy systems than conventional semiconductor components. They also increase power density and efficiency, reduce design time, lower costs, conserve board space, and speed up time-to-market. In addition, power management ICs (PMICs) combine multiple functions into a single device, to reduce the component count and board space needed to easily manage power in devices that are developed for the Internet of Things (IoT), consumer, medical, industrial, automotive, and many other applications. As subsystem designs get more complicated and board space becomes more valuable, many designers are considering using Silicon (Si) and Silicon Carbide (SiC) power modules instead of traditional discrete DC-DC Point-of-Load (POL) designs. This learning module discusses advanced DC power in terms of the benefits of power modules and PMICs, including their features, characteristics, and applications.
2. Objectives
Upon completion of this module, you will be able to:
Explain what power modules are and discuss their technology
Discuss features and benefits of using power modules and power management ICs
Describe Microchip's power module and power management IC products and their applications
Power modules are mechanically and thermally optimized for ease of assembly, long life, and reliable operation. While Silicon-based semiconductors and power modules represent the traditional market, Silicon carbide is an innovative, promising semiconductor material. It has new options for improving system efficiency when used for high operating temperature, high blocking voltage, and high switching frequency applications, due to its excellent electrical and thermal properties and resilience towards harsh ambient conditions. We will explore more of this technology and its use in power modules in the coming sections.
- 3.1 What Are Power Modules?
Power modules are integrated building blocks for the realization of a power converter. They are single-chip regulators that can efficiently perform a power conversion, having internal buck converters incorporating a PWM controller, power MOSFETs, inductors, and other compensation networks for the simplest, lowest-noise, and easiest-to-implement power conversion solutions into a single package. Control electronics such as gate drivers, sensing, and protection functions may be included inside the power module package, as well.
A power module exhibits significant advantages when long-term engineering and maintenance costs are considered. Its thermal packaging technology offers strong thermal performance, providing high current operation and high power density without the requirement for any fan or external heat sink, thus minimizing system cost.
SiC MOSFETs and SiC Schottky Barrier Diodes (SBDs) are designed with high-repetitive, unclamped inductive switching (UIS) capability, excellent gate oxide shielding, and channel integrity for robust operation. SiC MOSFETs maintain high UIS capability at approximately 10–25 Joules per Square Centimeter (J/cm2). These dies can be paired for use in power modules with various topologies. SiC MOSFET and SiC SBD products from Microchip are qualified to the automotive standard AEC-Q101.
- 3.2 Advantages of SiC Power Modules
Silicon Carbide devices solve design issues due to their unique features. SiC products can be combined with other devices, including 8-, 16-, and 32-bit microcontrollers, power management devices, analog sensors, touch and gesture controllers, and wireless connectivity solutions, to create a total system with lower overall system costs. These SiC products enable smaller magnetics, transformers, filters, and passives, resulting in compact form factors. They support a wide voltage range of 700V, 1200V, and 1700V, catering to various market applications.
SiC devices and power modules offer improved system efficiency with lower switching losses, reduced cooling needs, and ten times lower Failure In Time (FIT) rates for neutron susceptibility than comparable Insulated Gate Bipolar Transistors (IGBTs). They also have extremely low parasitic (stray) inductance at < 2.9 nH in SiC modules and higher power density compared to similar power topologies.
Common topologies used in SiC technology are Boost and Buck chopper, Dual diode, Full bridge, Phase leg, 3-Level NPC inverter, 3-Level T-Type inverter, Triple phase leg, and more. Microchip power modules are categorized based on input voltage range (up to 5.5V, 26V or 70V) or types, such as IGBT Modules, Si Diode Modules, Si MOSFET Modules, SiC Diode Modules, and SiC MOSFET Modules.
- 3.3 Packaging Techniques for SiC Power Modules
Several packaging technologies for SiC power modules have been developed, such as planar interconnection, press pack, chip embedded package, 3D interconnection, and hybrid packages. Stringent requirements are imposed on parasitic inductance and heat dissipation for SiC power module packages. Challenges do exist, however, in SiC power module packaging, due to the modules' features, such as high speed and high-frequency switching.
Compared with similar-sized Silicon counterparts, SiC MOSFETs have faster-switching speed, smaller form factors, lower switching loss, and higher switching frequency and efficiencies. These features of SiC MOSFETs pose substantial challenges to the packaging of SiC power modules, including fast switching speed and heat dissipation.
The development of any novel packaging technique usually encounters challenges, including material selection and packaging. SiC devices can be made to have a much thinner drift layer and more doping concentration. They have extremely high breakdown voltage (600V and up) and extremely low resistance relative to Silicon devices.
SiC occurs in different polymorphic crystalline structures known as polytypes. The most common SiC polytypes are 3C-SiC, 4H-SiC, and 6H-SiC, where C stands for cubic, H and R for hexagonal and rhombohedral, respectively. They are used for electronics manufacturing. The 4H-SiC is generally desired in power devices.
- 3.4 Custom Power Modules
Customized power modules using the Application Specific Power Modules (ASPM) concept provide a vehicle for developing a complete engineered solution with mix-and-match capabilities in terms of packaging, configuration, performance, and cost. Customized power modules are made of different sub-elements. Most of them are standard and can be reused to build many different solutions.
Module performance and reliability depends on the choice of assembly materials. With more closely matched materials, Temperature Coefficients of Expansion (TCEs) increase the module's lifetime by reducing the stress at both the interface and interior of the materials. The higher the thermal conductivity, the lower the junction-to-case thermal resistance, and the lower the delta of junction temperature of the device during operation will minimize the effect of power cycling on the dice. Figure 1 illustrates the different components of custom power modules.
Figure 1: Custom power module structure
Internal Printed Circuit Board: routes gate signals' tracks to small signal terminals. The board enables the mount of the gate circuit and protection in an intelligent power module.
Terminals: can be screw-on or solder pins, and provide power and signal connections with minimum parasitic resistance and inductance.
Substrates: consist of Al2O3, AlN, and Si3N4, which provide isolation and good heat transfer to the base plate.
Package: can be standard or custom, and ensures environmental protection and mechanical robustness.
Power Semiconductor Die: IGBT, MOSFET, diode, SiC, thyristor, and switching devices soldered to the substrates and connected by ultrasonic aluminum wire bonds.
Base Plate: improves the heat transfer to the heat sink. It is made of copper for good thermal transfer.
- 3.5 Integration Levels
Traditional power supply designs use analog ICs with fixed functionality to provide regulated power. Intelligent power supplies integrate a microcontroller (MCU) or Digital Signal Controller (DSC) for a fully programmable and flexible solution. Intelligent power supply applications include AC-to-DC converters, DC-to-DC converters, Uninterruptible Power Supplies, and more. Microchip offers various levels of integration for its intelligent power supplies (Table 1).
| Description | Technical Functions |
|---|---|
| Level 1: On/Off Control |
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| Level 2: Proportional Control |
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| Level 3: Topology Control |
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| Level 4: Full Digital Control |
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Table-1: Integration Levels
At Level 1, electronic intelligence augments a standard analog design. The intelligence provides limited on/off control functions such as start-up sequencing, automatic shutdown, and watchdog fault detection functions. At Level 2, this integration delivers additional digital control to the standard analog design, but also supplements existing Level 1 control features, enables the control of output voltage, voltage limits, current limits, and thermal limits. Level 3 permits the standard analog design to be reconfigured; for example, changing the analog loop configuration and swapping between multiple analog control loop filters can be achieved in the configurable digital portion of a design. At Level 4, full digital control replaces the standard analog control loop design and also provides the power management functions of Levels 1-3 integration. The power supply regulation function is directly controlled by the digital circuits on the processor and the software running on the processor. The full digital solution allows you to employ techniques that are not possible with an analog solution, including proprietary digital compensation algorithms, as well as non-linear predictive and adaptive control techniques.
In this section, we will discuss power management, power modules, and power monitoring products, along with their features and specifications.
- 4.1 Power Management
Figure 2: MCP16502 High-Performance PMIC for SAMA5DX/SAM9X6/SAMA7G MPUs
The MCP16502 is an optimally integrated PMIC, compatible with Microchip's EMPUs (Embedded Microprocessor Units) such as the SAMA5DX, SAM9X6, and SAMA7G family. With power being the most addressed MPU system design issue, the MCP16502 family of devices have been designed for and validated with Microchip's MPUs to greatly ease system design with risk-free, high performance power solutions while keep the solution size to the minimum. While integrating the high-efficiency, high accuracy, low quiescent current DC-DC Buck regulators and LDOs, the MCP16502 also enables easy migration across different generations of memory used with pin selectable voltages and pin-pin compatible variants for a fast time-to-revenue. Solution size is reduced with built-in power sequencing, protection, and fault management. Multi-mode operation and integrated I2C interface enables transitioning across different power states and dynamic voltage scaling for a highly efficient system in seamless co-ordination with the MPU's needs. The MCP16502 also passes automotive AEC-Q100 reliability testing and is available in a compact 32-pin 5mm x 5mm VQFN package.
Figure 3: MCP19117 Analog-based PWM controller with an Integrated 8-bit PICTM Microcontroller.
The MCP19117 is a mid-voltage (4.5-42V) analog-based PWM controller with an integrated 8-bit PICTM Microcontroller. This unique product family combines the performance of a high-speed analog solution, including high-efficiency and fast transient response, with the configurability and communication interface of a digital solution. Combining these solution types creates a new family of devices that maximizes the strengths of each technology to create a more cost-effective, configurable, high-performance power conversion solution. These products allow the development of flexible power supplies that can be configured perfectly to the target application with minimal external components. In addition, these devices can be programmed to dynamically respond to measurements or events within the system, dynamically tailoring the operation to the environment, or intelligently responding to faults for robust operation.
- 4.2 Power Modules
The MSCSM120AM042CT6LIAG device is a 1200V, 495A full Silicon Carbide power module in a phase-leg configuration. It is typically used in applications such as welding converters, switched mode power supplies, uninterruptible power supplies, and EV motor/traction drives. This device's benefits include a high efficiency converter, outstanding performance at high frequency operation, direct mounting to a heatsink (isolated package), low junction-to-case thermal resistance, low profile, and RoHS compliant. As shown in Figure 4, the device is a SP6C LI package, featuring an internal thermistor for temperature monitoring, M2.5 signals connectors, and M4 and M5 power connectors. The new package, with its compact form factor and higher power density, enables a reduced quantity of modules in parallel to realize complete systems.
(a) SP6C LI Package
(b) Electrical Schematic
Figure 4: MSCSM120AM042CT6LIAG Full Silicon Carbide Power Module
Figure 5: Augmented Switching Accelerated Development Kit
The ASDAK-MSCSM is an Augmented Switching Accelerated Silicon Carbide Development Kit. This kit simplifies driving SiC and enables rapid optimization of modules and systems. At the hub of each kit is a 2ASC Series Digital Programmable Gate Driver Core and SP6LI Low Inductance power module. These components are qualified and can take your design from concept to production. Users can easily adjust system performance using the Intelligent Configuration Tool (ICT) – no soldering required. This tool allows for modification of driving parameters like short circuit protection, on/off gate voltages, deadtime, DC Link and Temperature fault levels, and Augmented Switching profiles. Small changes to these parameters can yield improvements in switching efficiency, overshoot, ringing, and avalanche protection.
Additional hardware peripherals required to connect the gate driver and power module are also included. In total, each kit includes: 1x SP6LI SiC power module, 1x 2ASC Series Gate Driver Core, 1x ICT Download, 1x Module Adapter Board (MAB), 1x Programming Kit (ASBK-014), and 1x hardware mounting kit (ASBK-015). It is compatible with 1200V and 1700V SiC Power Modules. The following figure depicts the connection between the Gate Driver, MAB, and power module.
- 4.3 Power Monitoring
The PAC1934 is a four channel power/energy monitor with current sensor amplifier and bus voltage monitors that feed high resolution ADCs. Digital circuitry performs power calculations and energy accumulation. The PAC1934 enables energy monitoring with integration periods from 1 ms to up to 36 hours. Bus voltage, sense resistor voltage, and accumulated proportional power are stored in registers for retrieval by the system master or embedded controller. The sampling rate and energy integration period can be controlled over SMBus or I2C. Active channel selection, one-shot measurements, and other controls are also configurable. The PAC1934 uses real time calibration to minimize offset and gain errors. No input filters are required for this device.
(a) UQFN package
(b) Block Diagram
Figure 6: PAC1394 Single/Multi-Channel DC Power/Energy Monitor with Accumulator
- 4.4 Wireless SOM Application
In this section, we will discuss an application of the MCP16502. The MCP16502 is offered in different options, depending on the external memory type and target MPU platform. In this example, the MCP16502AC variant is utilized. The MCP16502AC variant is intended for an high-performance, efficiency optimized (i.e., 500 MHz) SAMA5D2 application with LPDDR2 memories. In this example, the MCP16502AC is utilized with the SAMA5D27 Wireless SOM1.
Figure 7: SAMA5D27 Wireless SOM1
The SAMA5D27 Wireless SOM1 (WLSOM1) is a small, single-sided System-On-Module (SOM) based on the high-performance 32-bit Arm
Cortex-A5 processor-based MPU + 2Gbit LPDDR2 System in Package, running up to 500 MHz, with the WILC3000 WiFi and Blutooth module and MCP16502 Power Management IC optimized for the module. The ATSAMA5D27-WLSOM1 is built on a common set of proven Microchip components to reduce time to market by simplifying hardware design and software development. It also simplifies design rules of the main application board, reducing overall PCB complexity and cost. The ATSAMA5D27-WLSOM1 is delivered with a free Linux distribution and bare metal C code examples.
The basic operation of the ATSAMA5D27-WLSOM1 requires a +5.0V input voltage supply and a VDDBU (+1.65V to +3.6V) input voltage supply, generally ensured by a backup battery. +5.0V power is supplied to the VDD_MAIN domain.
Power-on is controlled through the nSTART_SOM signal. This signal must be provided by the host board, for example via an automated reset controller or a push-button. The ATSAMA5D27-WLSOM1 module can operate from a single voltage supply (VDD_MAIN) with a value comprised between +3.0V and +5.5V and, with the MCP16502 PMIC device, internally generates the voltage supplies required by the SAMA5D2 processor and on-board components. The PMIC on-board switching regulators generate the 3.3V, 1.20V, 1.25V, and 1.8V voltage supplies required by the SAMA5D27 processor and on-board components. The ATSAMA5D27-WLSOM1 delivers external power supplies to the main board application, such as VDD_DDR (1.8V with 900 mA current capability), VDD_3V3 (3.3V with 600mA output current capability), and VLDO2 output (1.8V to 3.3V with 300 mA output current capability).
Figure 8: ATSAMA5D27-WLSOM1 Power Architecture
Note: CAUTION: As a general design rule, it is recommended to connect all input supply pins, except VDDFUSE which must be connected to GND by a 100 Ohms resistor if not used, to your power supply and at least a matching number of ground (GND) pins. For the best EMI performance, it is recommended to connect ALL ground pins of the ATSAMA5D27-WLSOM1 module to a solid ground plane.
*Trademark. Microchip is a trademark of Microchip Inc. Other logos, product and/or company names may be trademarks of their respective owners.
Related ComponentsBack to Top
The element14 ESSENTIALS of Power Modules discusses advanced DC power in terms of the benefits of power modules and PMICs, including their features, characteristics, and applications.
Power Modules
The MSCSM120AM02CT6LIAG device is a 1200-Volt, 947-Amp full Silicon Carbide power module in a phase leg configuration, featuring very low stray inductance in a SP6C LI package.
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ASDAK-MSCSM120AM042CT6LIAG-01 Development Kit, MSCSM120AM042CT6LIAG, SiC MOSFET Modules & Systems
The Accelerated Silicon Carbide Development Kit includes the hardware and software elements required to rapidly optimize the performance of the Microchip family of SP6LI Low Inductance SiC modules and systems. This tool enables designers to adjust system performance through software upgrades using the AgileSwitch Intelligent Configuration Tool (ICT) and a device programmer. The ICT offers configuration of different drive parameters including on/off gate voltages, DC link, and temperature fault levels and Augmented Switching
technology profiles. The kit comes with power module, gate driver core, module adaptor board, device programmer, and assembly hardware.
Power Management
The MCP19117 is a mid-voltage (4.5-42V) analog-based PWM controller with an integrated 8-bit PICTM Microcontroller. This product family combines the performance of a high-speed analog solution, including high-efficiency and fast transient response, with the configurability and communication interface of a digital solution. These products allow designers to develop flexible power supplies that can be configured to the target application with minimal external components. In addition, these devices can be programmed to dynamically respond to measurements or events within the system, dynamically tailoring the operation to the environment, or intelligently responding to faults for robust operation.
The MCP16502 is an optimally integrated PMIC compatible with Microchip's eMPUs (Embedded Microprocessor Units), requiring Dynamic Voltage Scaling (DVS) with the use of High-Performance mode (HPM). It is compatible with SAMA5DX and SAM9X6 MPUs, which are supported by dedicated device variants that optimize the solution BOM. The MCP16502 integrates four DC-DC Buck regulators and two auxiliary LDOs, and provides a comprehensive interface to the MPU, which includes an interrupt flag and a 1 MHz I2C interface. All Buck channels can support loads up to 1A and are 100% duty cycle-capable. Two 300 mA LDOs are provided such that sensitive analog loads can be supported. The DDR memory voltage (Buck2 output) is selectable by means of a 3-state input pin. The voltage selection set allows easy migration across different generations of memory. The default power channel sequencing is built-in according to the requirements of the MPU. A dedicated pin (LPM) facilitates the transition to Low-Power modes and the implementation of Backup mode with DDR in self-refresh (Hibernate mode). The MCP16502 features a low no-load operational quiescent current and draws less than 10 μA in full shutdown. Active discharge resistors are provided on each output. All Buck channels support safe start-up into pre-biased outputs.
Power Monitoring
The PAC1934 is a four channel power/energy monitor with current sensor amplifier and bus voltage monitors that feed high resolution ADCs. Digital circuitry performs power calculations and energy accumulation. It enables energy monitoring with integration periods from 1 ms to up to 36 hours. Bus voltage, sense resistor voltage, and accumulated proportional power are stored in registers for retrieval by the system master or embedded controller.The sampling rate and energy integration period can be controlled over SMBus or I2C. Active channel selection, one-shot measurements, and other controls are also configurable. The PAC1934 uses real time calibration to minimize offset and gain errors. No input filters are required for this device.
For more information: about Microchip power management products, click here for more information.
Test Your KnowledgeBack to Top
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