What is a Power Management IC (PMIC): Functions and Applications

A Power Management IC (PMIC) is a type of integrated circuit designed to manage the power requirements of the host system. It efficiently distributes, regulates, converts, and monitors electrical power for various components within a device, such as processors, memory units, and peripherals. As the demand for compact, battery-powered, and high-performance devices continues to grow, PMICs have become an essential part of system design across industries. Embedded and application processors and other components in complex systems require multiple power rails and multiple power domains. See the full process of PCB manufacturing from here.

Using discrete devices for power management in these types of systems can be costly. Power Management Integrated Circuits (PMICs), which integrate multiple voltage regulators and control circuits into a single chip, are excellent options for implementing complete power supply solutions. They reduce component count and board space while easily and cost effectively managing system power. This article explores what a PMIC is, its core functions, and its wide range of applications in modern electronics.

How does PMIC work?

The semiconductor community sometimes analogizes PMIC as much like the “heart” in the human body, “pumping” blood to organs, to keep them working in function. PMIC holds the role of the “voltage converter” that converts voltage from the battery or power source. It adjusts, coordinates, and distributes suitable voltage power to each component of the electrical circuit.

PMIC handles the voltage sequencing of the power system, provides power to various loads, and protects against overvoltage, undervoltage, overcurrent, or other thermal issues. Thus, the PMIC chip enhances higher efficiency in energy management, limiting damages, and extending batteries’s lifespan in electronic devices. In a complex system a PMIC do:

• Power sequencing: Turning on and ramping up the voltage at startup and shutdown at the right time and in the right sequence, compared to other rails, and within the right levels

• Voltage programmability: Adjusting the voltage in response to multiple power-saving or performance-enhancing operating modes

• Monitoring and control: Monitoring incoming and outgoing voltage and current and thermal limits during operation and sending a signal to trigger the components to respond to any fault conditions

• Multiple operating modes: Using aggressive power states to reduce the power consumption of the system.

Types of PMIC:

PMIC’s power management scope is relatively broad, including power conversion (DC-DC, AC-DC, DC-AC), distribution and detection of power voltage, battery protection and charging, LED control, etc. Therefore, PMIC is classified into various types based on their applications and functions.

1. Linear Regulators:

Taking linear regulators into account, a crucial type of integrated circuit that must be mentioned is the Low Dropout (LDO) voltage regulator. It can continuously generate a stable output voltage (VOUT) when the difference between input voltage (VIN) and output voltage (VOUT) remains at a very small level. Linear regulators have some advantages and disadvantages. As they have

• No switching noise
• Simpler design (usually consists of a voltage reference, amplifier, and pass element).
• Generate significant heat and lower in efficiency
• Large size due to transformer windings

2. Switching Regulator:

Switching regulators convert VIN into different VOUT through a switching element, use external inductors, and capacitors to smooth the output voltage (VOUT). Switching regulators have been proven to be more efficient and can support higher output currents than linear regulators. They come in different types:

• BUCK Converters : VOUT < VIN
• Boost Converters : VOUT > VIN

BUCK Converter: VOUT < VIN

The BUCK converter is a step-down voltage regulator, producing output voltage (VOUT) that is lower than the input voltage (VIN). A BUCK Converter consists of an inductor, a switching FET (Field-Effect Transistor) or diode, a capacitor, and an error amplifier with a switching control circuit.

It operates by modulating the on-off time of the metal-oxide-semiconductor field-effect transistor (MOSFET) and supplying power to the inductor. The high efficiency of the Buck converter is generated from its MOSFET being fully turned on or off. It does not operate in the intermediate state between on and off (resistance) as in linear regulators.

The BUCK Converter generates a switching waveform in either pulse-width modulation (PWM) or pulse-frequency modulation (PFM) mode. After that, the converter filters it using external components such as capacitors and inductors outside the chip to create the output voltage (VOUT). This efficient voltage conversion method contributes to extending battery life, reducing system temperature, and allowing for compact product sizes.

BUCK Converters are utilized in various applications, namely providing power through USB connections and other peripheral devices for computers. They are also used in smartphones, tablets, mobile devices, and a wide range of other electronic devices.

BOOST Converter: VOUT > VIN

The Boost Converter is a boost process, regulating output voltage (VOUT) from its input voltage (VIN). For instance, the Boost Converter is proven to be beneficial when you need to increase the DC input voltage from 3.3V to an output voltage (VOUT) of 5.0V. Such voltage boosting is commonly seen in many applications using Li-ion or LiPo batteries.

A BOOST Converter comprises components much similar to a resistive circuit (inductor, field-effect transistor [FET] or diode, capacitor, and error amplifier with a switch control circuit), but with different connections. It operates by adjusting the on-time of the MOSFET and supplying power to the inductor.

BUCK-BOOST Converter: VOUT can be flexibly adjusted (lower, higher, or equal to VIN)

The BUCK-BOOST Converter is a “switching mode converter”, combining both Buck and Boost converters’ principles into a single converter model (regulator). It is able to manage a wide range of input and output voltages. The control circuit adjusts the on-off time of the MOSFET to decrease or increase the input voltage as needed to achieve the desired output voltage (VOUT).

Key Functions of a PMIC

• Voltage Regulation
• Power Sequencing
• Battery Management
• Power Path Management
• Thermal Management
• Power Monitoring & Diagnostics

Discrete Components vs PMICs

Systems in modern electronics are typically based on Printed Circuit Boards (PCBs). A PCB has multiple active and passive hardware components that are arranged to enable the system to function. Functions that can’t be done in hardware are typically done in software or firmware. To solve the challenges of discrete power management, the semiconductor industry has developed an integrated solution known as a Power Management IC (PMIC). A PMIC encompasses the DC-DC conversion, LDO regulation, power sequencing, voltage programmability, monitoring and control, multiple operating mode support and other hardware to supply the complex power tree in a system or application.

Conclusion:

A Power Management IC (PMIC) is a cornerstone of modern electronics, enabling energy-efficient, compact, and reliable power delivery across a range of industries. As devices continue to demand more functionality in smaller footprints, the role of PMICs will only grow more critical.

By integrating multiple power functions into a single chip, PMICs not only enhance performance and battery life but also simplify design and reduce costs. Whether you're designing a smartwatch or an electric vehicle, understanding and selecting the right PMIC is fundamental to building smarter, more efficient systems.