Power Management ICs: How they work and how to choose them

In the ongoing quest for smaller, smarter, and more powerful electronic devices, engineers are consistently challenged to manage power efficiently. Every component on a printed circuit board (PCB), ranging from the most powerful microprocessor to the simplest LED, requires a stable and precise voltage to operate correctly. This is where the Power Management Integrated Circuit (PMIC) plays a crucial role in modern electronic design.

These advanced chips are more than just simple power switches; they serve

as the central control unit for a device’s entire power system. Understanding the role of a Power Management Integrated Circuit (PMIC) and knowing how to select the right one is crucial for engineers, purchasing managers, and original equipment manufacturers (OEMs) seeking to create reliable, efficient, and competitive products. This guide provides an in-depth examination of PMICs, covering their functions, core technologies, and key factors to consider during the selection process.

In the ongoing quest for smaller, smarter, and more powerful electronic devices, engineers are consistently challenged to manage power efficiently. Every component on a printed circuit board (PCB), ranging from the most powerful microprocessor to the simplest LED, requires a stable and precise voltage to operate correctly. This is where the Power Management Integrated Circuit (PMIC) plays a crucial role in modern electronic design.

These advanced chips are more than just simple power switches; they serve as the central control unit for a device’s entire power system. Understanding the role of a Power Management Integrated Circuit (PMIC) and knowing how to select the right one is crucial for engineers, purchasing managers, and original equipment manufacturers (OEMs) seeking to create reliable, efficient, and competitive products. This guide provides an in-depth examination of PMICs, covering their functions, core technologies, and key factors to consider during the selection process.

What is a Power Management IC?

A Power Management IC (PMIC) is essentially a single chip that integrates multiple power-related functions. When designing the power system for a portable smart device using individual, discrete components, separate integrated circuits (ICs) are required for various tasks, such as voltage conversion, multiple regulators for different voltage rails, a battery charger, and supervisors to monitor voltage levels. Additionally, you would need logic circuits to control the power-up sequence. This approach would occupy a significant portion of the printed circuit board (PCB) just for power management, resulting in a larger device, a more complex bill of materials (BOM), and an increased number of potential points of failure.

A PMIC addresses this issue by integrating several functions into one highly efficient package, offering multiple key advantages:

Reduced Footprint: By integrating various functions, a PMIC significantly minimizes the board space required, allowing for the design of smaller, more compact devices.
Simplified BOM: A single PMIC consolidates several discrete components, simplifying the BOM, streamlining procurement, and reducing assembly complexity.
Improved Reliability: Fewer external components and interconnects reduce potential failure points, resulting in a more robust and reliable end product.
Enhanced Performance: The close integration of functions on a single chip enhances performance, improves communication between functional blocks, and provides more efficient power delivery.

What is a Power Management IC?

A Power Management IC (PMIC) is essentially a single chip that integrates multiple power-related functions. When designing the power system for a portable smart device using individual, discrete components, separate integrated circuits (ICs) are required for various tasks, such as voltage conversion, multiple regulators for different voltage rails, a battery charger, and supervisors to monitor voltage levels. Additionally, you would need logic circuits to control the power-up sequence. This approach would occupy a significant portion of the printed circuit board (PCB) just for power management, resulting in a larger device, a more complex bill of materials (BOM), and an increased number of potential points of failure.

A PMIC addresses this issue by integrating several functions into one highly efficient package, offering multiple key advantages:

Reduced Footprint: By integrating various functions, a PMIC significantly minimizes the board space required, allowing for the design of smaller, more compact devices.
Simplified BOM: A single PMIC consolidates several discrete components, simplifying the BOM, streamlining procurement, and reducing assembly complexity.
Improved Reliability: Fewer external components and interconnects reduce potential failure points, resulting in a more robust and reliable end product.
Enhanced Performance: The close integration of functions on a single chip enhances performance, improves communication between functional blocks, and provides more efficient power delivery.

The Core Functions of a PMIC

Modern PMICs are advanced components designed to manage a variety of tasks. While the specific features can differ, most include these fundamental functions.

The Core Functions of a PMIC

Modern PMICs are advanced components designed to manage a variety of tasks. While the specific features can differ, most include these fundamental functions.

Linear vs. Switching Regulators

Voltage regulation in a PMIC is achieved using two main technologies: linear regulators and switching regulators. Most PMICs utilize a combination of both to optimize overall system performance.

A linear regulator functions like a smart variable resistor, converting excess energy into heat to reduce a higher voltage to a lower one. The most common type of linear regulator is the Low-Dropout (LDO) regulator, which operates with a minimal difference between the input and output voltages.

A switching regulator utilizes a power transistor, an inductor, and a capacitor to switch power on and off at high frequencies efficiently, converting voltage effectively. They are available in several topologies, including:

Buck Converter: Steps voltage down.
Boost Converter: Steps up the voltage.
Buck-Boost Converter: Can step the voltage up or down from the input.

Here’s a comparison to help you understand the trade-offs:

Feature	Linear Regulator (LDO)	Switching Regulator
Efficiency	Low to moderate (40-75%). Inefficiency is lost as heat.	Very high (85-98%)
Output Noise (EMI)	Very low. Ideal for noise-sensitive analog or RF circuits.	Higher. It can introduce switching noise that may need filtering.
Complexity	Simple, requires few external components.	More complex, requires external inductors and capacitors.
Size	It can be very small for low power, but heat sinks may be needed.	It can be very compact due to its high frequency, enabling the use of small inductors.
Cost	Generally, a lower cost for the component itself.	It may be more expensive, but system-level savings are still possible.
Best Use Case	Powering low-current, noise sensitive components like audio codecs or sensors.	Powering high current digital cores, processors, and battery charging.

Linear vs. Switching Regulators

Voltage regulation in a PMIC is achieved using two main technologies: linear regulators and switching regulators. Most PMICs utilize a combination of both to optimize overall system performance.

A linear regulator functions like a smart variable resistor, converting excess energy into heat to reduce a higher voltage to a lower one. The most common type of linear regulator is the Low-Dropout (LDO) regulator, which operates with a minimal difference between the input and output voltages.

A switching regulator utilizes a power transistor, an inductor, and a capacitor to switch power on and off at high frequencies efficiently, converting voltage effectively. They are available in several topologies, including:

Buck Converter: Steps voltage down.
Boost Converter: Steps up the voltage.
Buck-Boost Converter: Can step the voltage up or down from the input.

Here’s a comparison to help you understand the trade-offs:

Feature	Linear Regulator (LDO)	Switching Regulator
Efficiency	Low to moderate (40-75%). Inefficiency is lost as heat.	Very high (85-98%)
Output Noise (EMI)	Very low. Ideal for noise-sensitive analog or RF circuits.	Higher. It can introduce switching noise that may need filtering.
Complexity	Simple, requires few external components.	More complex, requires external inductors and capacitors.
Size	It can be very small for low power, but heat sinks may be needed.	It can be very compact due to its high frequency, enabling the use of small inductors.
Cost	Generally, a lower cost for the component itself.	It may be more expensive, but system-level savings are still possible.
Best Use Case	Powering low-current, noise sensitive components like audio codecs or sensors.	Powering high current digital cores, processors, and battery charging.

How to Choose the Right PMIC

Choosing the right PMIC can be overwhelming due to the numerous options available. However, using a structured approach can simplify the selection process and help you find the ideal fit for your application.

Step 1: Map Your System’s Power Tree

Begin by creating a “power tree” diagram. List every component that requires power, along with its required voltage and both maximum and typical current draw. This map outlines your essential requirements, including the number of output rails needed, their voltages, and their current capacities.

Step 2: Prioritize Key Performance Metrics

Does a battery power your device? If so, maximizing runtime should be your top priority. If it’s powering a sensitive radio or audio circuit, minimizing noise from the LDO outputs becomes critical. Clearly define your primary performance criteria, as this will significantly influence your selection.

Step 3: Determine the Necessary Level of Integration

Consider all the functions you require. Do you need battery charging, a real-time clock, or power sequencing? Opting for a PMIC (Power Management Integrated Circuit) that incorporates these features can help you save both space and costs. On the other hand, if your requirements are simple, a less integrated and more affordable PMIC may be sufficient.

Step 4: Define Your Control and Communication Needs

Many power management integrated circuits (PMICs) include an I²C or SPI interface. This enables a host microcontroller to dynamically control output voltages, monitor system status, and configure settings in real-time. Such functionality is crucial for techniques like dynamic voltage scaling, which reduces processor voltage during idle periods to conserve power.

Step 5: Don’t Overlook Protection and Safety Features

Ensure the PMIC has robust protection features, including thermal shutdown, overcurrent protection, overvoltage protection, and under-voltage lockout. These features act as your primary defense against fault conditions that could potentially damage your device.

How to Choose the Right PMIC

Choosing the right PMIC can be overwhelming due to the numerous options available. However, using a structured approach can simplify the selection process and help you find the ideal fit for your application.

Step 1: Map Your System’s Power Tree

Begin by creating a “power tree” diagram. List every component that requires power, along with its required voltage and both maximum and typical current draw. This map outlines your essential requirements, including the number of output rails needed, their voltages, and their current capacities.

Step 2: Prioritize Key Performance Metrics

Does a battery power your device? If so, maximizing runtime should be your top priority. If it’s powering a sensitive radio or audio circuit, minimizing noise from the LDO outputs becomes critical. Clearly define your primary performance criteria, as this will significantly influence your selection.

Step 3: Determine the Necessary Level of Integration

Consider all the functions you require. Do you need battery charging, a real-time clock, or power sequencing? Opting for a PMIC (Power Management Integrated Circuit) that incorporates these features can help you save both space and costs. On the other hand, if your requirements are simple, a less integrated and more affordable PMIC may be sufficient.

Step 4: Define Your Control and Communication Needs

Many power management integrated circuits (PMICs) include an I²C or SPI interface. This enables a host microcontroller to dynamically control output voltages, monitor system status, and configure settings in real-time. Such functionality is crucial for techniques like dynamic voltage scaling, which reduces processor voltage during idle periods to conserve power.

Step 5: Don’t Overlook Protection and Safety Features

Ensure the PMIC has robust protection features, including thermal shutdown, overcurrent protection, overvoltage protection, and under-voltage lockout. These features act as your primary defense against fault conditions that could potentially damage your device.

Suntsu’s PMIC Solutions

Choosing the right component is only part of the challenge. You also need a dependable supply chain partner to ensure you receive the necessary parts on time. At Suntsu, we are an authorized distributor for leading manufacturers of Integrated Circuits, offering a robust portfolio of Power Management Integrated Circuits (PMICs).

Our authorized line card features innovative suppliers like:

3PEAK: A provider of high-performance analog and mixed-signal ICs, offering PMICs with excellent performance for demanding applications.
Unisonic Technologies (UTC): Specializing in a broad range of cost-effective and reliable power management ICs, including a wide variety of LDOs and switching regulators perfect for consumer and industrial products.
Taejin Technology: A trusted manufacturer of power semiconductors, providing stable and high-quality regulators that form the building blocks of robust power systems.

The Suntsu Advantage

PMICs (Power Management Integrated Circuits) are often highly specialized components, making them vulnerable to market fluctuations, long lead times, and allocation challenges. In today’s unpredictable landscape, having a resilient supply chain is essential, not just a luxury.

Suntsu’s hybrid business model offers a unique advantage in this regard. In addition to our authorized lines, our expertise in global sourcing and shortage mitigation enables us to secure the components you need to keep your

production lines operational. Our inventory management solutions provide you with visibility and control over your stock, allowing you to reduce costs and minimize disruptions. We aim to partner with you not only to sell components but also to ensure the long-term health and success of your projects.

The Suntsu Advantage

PMICs (Power Management Integrated Circuits) are often highly specialized components, making them vulnerable to market fluctuations, long lead times, and allocation challenges. In today’s unpredictable landscape, having a resilient supply chain is essential, not just a luxury.

Suntsu’s hybrid business model offers a unique advantage in this regard. In addition to our authorized lines, our expertise in global sourcing and shortage mitigation enables us to secure the components you need to keep your production lines operational. Our inventory management solutions provide you with visibility and control over your stock, allowing you to reduce costs and minimize disruptions. We aim to partner with you not only to sell components but also to ensure the long-term health and success of your projects.

Ready to power your next innovation? Contact Suntsu’s team of experts to discuss your design and discover the perfect PMIC solution today.

Get A Quote

FAQs

What are some best practices for thermal management?

Effective thermal management is crucial for PMIC reliability. Key strategies include: maximizing the copper ground plane area on the PCB connected to the PMIC’s thermal pad, using thermal vias to transfer heat to inner or bottom layers of the board, ensuring proper airflow in the enclosure, and operating the internal switching regulators at their most efficient point to minimize heat generation in the first place.

What is the difference between QFN and BGA packages for PMICs?

QFN (Quad Flat No-leads) packages have pins exposed on the perimeter, which makes them easier to visually inspect and rework, and they often have a large thermal pad on the bottom. BGA (Ball Grid Array) packages have solder balls underneath the entire chip, allowing for a much higher pin density in a smaller footprint. You would choose BGA for highly complex PMICs with many input/output pins in space-constrained designs, while a QFN is often preferred for simpler PMICs where ease of manufacturing and thermal performance are key.

What is a 'Power Good' (PGOOD) signal on a PMIC?

A ‘Power Good’ (PGOOD) signal is a digital output from the PMIC that indicates whether the output voltages have reached their nominal levels and are stable. This signal is typically used as an enable or reset signal for a downstream processor or microcontroller, ensuring that the processor does not attempt to turn on until its power supply is stable and ready.

Besides filtering, what are some PCB layout techniques to mitigate EMI?

To minimize electromagnetic interference (EMI), you should place input decoupling capacitors as close as possible to the PMIC’s input pins, keep the high-frequency switching loop (the path from the switch, inductor, and output capacitor) as small and tight as possible, use a solid ground plane directly under the PMIC, and avoid running sensitive analog or digital traces directly underneath the switching inductor.

What is Dynamic Voltage Scaling (DVS), and how do PMICs enable it?

Dynamic Voltage Scaling is a power-saving technique where the voltage supplied to a component, like a microprocessor, is adjusted in real-time based on its performance needs. When the processor is idle or performing simple tasks, the system can command the PMIC to lower the supply voltage, significantly reducing power consumption. When high performance is needed, the voltage is raised. PMICs with programmable regulators are essential for implementing DVS.

Power Management ICs: Functions and How to Select the Right One

What is a Power Management IC?

What is a Power Management IC?

The Core Functions of a PMIC

The Core Functions of a PMIC

Linear vs. Switching Regulators

Linear vs. Switching Regulators

How to Choose the Right PMIC

Step 1: Map Your System’s Power Tree

Step 2: Prioritize Key Performance Metrics

Step 3: Determine the Necessary Level of Integration

Step 4: Define Your Control and Communication Needs

Step 5: Don’t Overlook Protection and Safety Features

How to Choose the Right PMIC

Step 1: Map Your System’s Power Tree

Step 2: Prioritize Key Performance Metrics

Step 3: Determine the Necessary Level of Integration

Step 4: Define Your Control and Communication Needs

Step 5: Don’t Overlook Protection and Safety Features

Suntsu’s PMIC Solutions

The Suntsu Advantage

The Suntsu Advantage

FAQs

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