Ⅰ. The core function of the power module is to realize the conversion of electrical energy forms, so the input and output voltage type (AC/DC) is the most basic classification basis.

1. AC-DC power module (AC to DC)

Definition: A module that converts alternating current (AC, such as 220V/110V mains) into direct current (DC).

Features: Usually includes rectification (AC→pulsating DC), filtering (smooth pulsation), voltage regulation (stable output) and other links.

Typical applications: Home adapters (such as mobile phone chargers), industrial equipment power input stages, LED driver power supplies, etc.

2. DC-DC power module (DC to DC)

Definition: A module that converts one DC voltage into another DC voltage (such as high voltage to low voltage, low voltage to high voltage).

Features: No rectification link is required, and it is directly achieved through switch conversion (such as Buck buck, Boost boost, Buck-Boost buck-boost) or linear adjustment.
Typical applications: battery-powered devices (such as laptops, drones), communication equipment power distribution, automotive electronics (12V→5V/3.3V), etc.

II. Classification by output characteristics

1. Voltage-stabilized power supply module

Definition: A module whose output voltage is less affected by load or input fluctuations and can remain basically stable.
Technical implementation: Dynamically adjust the output through a feedback circuit (such as an error amplifier + PWM control).
Typical types: linear regulator (LDO), switching regulator (such as synchronous buck/boost module).
Application scenarios: Equipment with high voltage accuracy requirements (such as MCU, sensors, precision instruments).

2. Non-stabilized power supply module

Definition: The output voltage varies greatly with load or input, and only provides a rough DC voltage.
Features: Simple structure, low cost, but requires an external voltage-stabilized circuit or the load itself has a wide voltage tolerance range.
Typical types: simple DC-DC converters (without feedback loops), some industrial-grade rough power supply modules.
Application scenarios: scenarios with low voltage accuracy requirements (such as indicator lights and relay drives).

Ⅲ. Classification by conversion principle

According to the way of energy conversion, it can be divided into linear power supply module and switching power supply module (switch mode power supply, SMPS).

1. Linear power supply module

Principle: By adjusting the linear conduction state of the tube (such as transistor), the excess electric energy is consumed to stabilize the output voltage.

Features:

Advantages: small ripple (usually ≤10mV), simple circuit, low electromagnetic interference (EMI);

Disadvantages: low efficiency (η≈output voltage/input voltage, extremely low efficiency when the input-output voltage difference is large), large size (large heat sink required).

Typical applications: low-power precision equipment (such as audio amplifiers, medical instruments, laboratory power supplies).

2. Switching power supply module (SMPS)

Principle: Through the rapid on and off of high-frequency switching tubes (such as MOSFETs), the electric energy is stored in the inductor/capacitor, and then the stable voltage is output through filtering.
Features:
Advantages: high efficiency (η can reach 80%~95%), small size, high power density;
Disadvantages: large ripple (usually tens to hundreds of mV), high-frequency noise (additional filtering required), EMI requires strict design.

Typical applications: high-power scenarios (such as industrial control, communication base stations, server power supplies).

Ⅳ. classification by isolation characteristics

According to whether there is electrical isolation between input and output (i.e., whether it passes through magnetic coupling components such as transformers), it can be divided into isolation modules and non-isolation modules.

1. Isolated power module

Definition: The input and output are isolated by magnetic/optical coupling components such as transformers and optocouplers, without direct electrical connection.

Features:
High safety (meets the isolation withstand voltage requirements of safety standards such as UL and CE, usually ≥1kV);
Can block ground loop interference (suitable for complex systems with multiple devices sharing the same ground);
High cost (transformers and other components required), large size.

Typical applications: medical equipment (need to prevent electric shock), industrial fieldbus (avoid ground potential difference interference), high-voltage system monitoring (isolation measurement).

2. Non-isolated power module

Definition: The input and output are directly connected through semiconductor devices without electrical isolation.

Features:
Advantages: simple structure, low cost, small size, fast response speed;
Disadvantages: low safety (input and output share the same ground, susceptible to surge or short circuit), possible ground loop noise.

Typical applications: cost- and volume-sensitive scenarios (such as consumer electronics, low-power LED drivers, battery charging).

V. Classification by application scenarios

Based on the industry or environmental requirements of the terminal equipment, power modules can be divided into the following types:

1. Industrial-grade power module

Features: adapt to wide temperature (-40℃~+85℃), high reliability (MTBF≥100,000 hours), anti-vibration/electromagnetic interference.

Applications: industrial PLC, servo drive, robot controller, CNC machine tools.

2. Consumer Electronics Power Modules

Features: miniaturization (such as SMD packaging), low cost, and consumer-grade temperature and humidity range (0℃~+70℃).

Applications: mobile phone/tablet chargers, laptop power adapters, smart home devices.

3. Communication Power Modules

Features: high stability (output voltage accuracy ±1%~±3%), redundant design (support hot plugging), support for multiple outputs (such as 5V/12V/24V).

Applications: 5G base stations, switches, routers, and communication room power systems.

4. Automotive Electronics Power Modules

Features: wide voltage fluctuation resistance (to cope with 9V~16V when the car starts or even 40V surges due to load dump), high temperature resistance (-40℃~+125℃), and AEC-Q100 certification.

Applications: on-board chargers (OBC), BMS (battery management system), and ADAS sensor power supply.

Ⅵ. Classification by power level

According to the output power, it can be divided into low power, medium power and high power modules.

VII. Other special types

In addition to the above classifications, there are also some special power modules for specific needs:

Redundant power module: multiple modules are connected in parallel, supporting N+1 redundancy (such as server power supply), and automatically switching when a single module fails to ensure continuous power supply to the system.

High-voltage power module: output voltage ≥1kV (such as X-ray machine, plasma equipment), requiring special insulation design and safety protection.

Battery management module (BMS): DC-DC module with integrated charging management, overcharge/over-discharge protection, and balancing functions, used for lithium battery packs (such as electric vehicles, energy storage systems).

Constant current source module: stable output current (not voltage), used in scenarios such as LED driving, electroplating, lasers, etc. that require precise current control.

Summary

The classification of power modules needs to be comprehensively selected in combination with specific needs (such as input and output type, isolation requirements, power size, and application scenarios). For example, medical equipment requires isolation modules to ensure safety, industrial control requires wide temperature and high reliability modules, and consumer electronics focuses on miniaturization and cost. Understanding these classifications can help engineers quickly match the optimal solution for the target scenario.