In today's ubiquitous electronic devices, almost any device that needs to be plugged into a wall socket (alternating current, AC) for operation cannot do without a key role on the internal circuit board: the AC-DCAC-DCAC-DC chip (usually referring to the AC-DC power converter or controller chip). Its core mission is to safely, efficiently, and stably convert the ubiquitous alternating current (AC) in our daily lives into direct current (DC) required for the internal circuits of electronic devices. The reasons for using it can be summarized as follows:
The 'blood' demand for AC-DCAC-DC electronic devices: direct current (DC) AC-DCAC-DC
The core of modern electronic devices such as microprocessors, memory chips, sensors, logic circuits, display screens, etc. almost invariably require stable, constant voltage, and directional direct current (DC) from AC-DC-AC-DC to function properly. Alternating current (AC) periodically changes direction and magnitude, and directly supplying these components can cause them to malfunction or even damage.
AC-DC-AC-DC voltage matching: from high voltage to low voltage AC-DC-AC-DC
The AC power provided by the AC-DC grid is usually high voltage (such as 110V/220V). The working voltage of internal chips in electronic devices is usually low voltage DC, such as 5V, 3.3V, 1.8V or even lower. One of the core functions of AC-DC chips (and their peripheral circuits) is to significantly reduce the voltage of high-voltage AC power and convert it into precise low-voltage DC power required by the equipment. Internal transformers (in isolated designs) or complex switch circuits are key to achieving this.
AC-DC-AC-DC rectification and filtering: from fluctuation to smoothing AC-DC-AC-DC
The first step in the AC-DC conversion process is usually AC-DC-AC-DC rectification (using diodes or bridge rectifiers), which converts bidirectional AC power into unidirectional pulsating DC power. But this is not enough, pulsating DC contains huge ripples that can interfere with circuit operation. AC-DC chips (especially switch power controllers) drive switching transistors (such as MOSFETs) through precise control loops, and work with peripheral inductors and capacitors to efficiently filter and stabilize AC-DC-AC-DC, ultimately outputting pure DC power with small ripple and stable voltage. Compared to traditional bulky linear transformers, modern switching power supply chips greatly improve efficiency and power density.
AC-DCAC-DC Safety Isolation: Ensuring Life and Equipment AC-DCAC-DC
It is extremely dangerous for AC-DC to directly connect equipment to the high-voltage power grid. AC-DC chips (in isolated designs) are typically designed to drive an AC-DC-AC-DC high-frequency isolation transformer.
The AC-DC transformer realizes the electrical isolation of AC-DC-AC-DC: the input (high voltage AC side) and output (low voltage DC side) are physically separated without direct electrical connection.
AC-DC AC-DC-AC-DC Key role: AC-DC-AC-DC
AC-DC AC-DC-AC-DC prevents electric shock: The AC-DC-AC-DC isolation barrier ensures that even if there is a fault in the low-voltage circuit inside the device, users will not directly connect to the high-voltage power grid when they come into contact with the output terminal (such as USB port, device casing), ensuring personal safety.
AC-DC AC-DC-AC-DC interference suppression: AC-DC-AC-DC isolation helps block the transmission of noise (such as surges and spikes) from the power grid to sensitive electronic devices, while also preventing internal noise pollution of the power grid.
AC-DCAC-DC Efficiency Improvement and Energy Conservation: AC-DCAC-DC
Early linear power supplies of AC-DC (using large transformers and voltage regulators) had low efficiency (usually only 30% -60%), large volume, and severe heat generation. Modern AC-DC-AC-DC switching power supplies based on AC-DC controller chips have extremely high efficiency (usually up to 80% -95% or more).
Advantages of AC-DC-AC-DCC-DC: AC-DC-AC-DC
AC-DC AC-DC-AC-DC Energy saving: AC-DC-AC-DC greatly reduces energy waste and meets environmental protection requirements.
AC-DC AC-DC-AC-DC generates less heat: AC-DC-AC-DC reduces heat dissipation requirements and heat sink volume.
AC-DC AC-DC-AC-DC is small in size and light in weight: The AC-DC-AC-DC high-frequency switching technology allows for the use of smaller magnetic components (transformers, inductors) and capacitors, making power adapters very compact (such as mobile phone chargers).
AC-DCAC-DC Power Factor Correction (PFC): AC-DCAC-DC
AC-DC, for devices with high power (usually>75W), simple rectification and filtering can cause distortion of the input current waveform, generate a large number of harmonics, reduce the power factor of the power grid, resulting in energy waste and pollution to the power grid. Many modern AC-DC chips integrate or have dedicated PFC controller chips working together to implement AC-DC-AC-DC active power factor correction AC-DC-AC-DC technology, which allows the input current waveform to follow the input voltage waveform (close to a sine wave), significantly improving the power factor (close to 1), meeting strict energy efficiency regulations (such as 80 PLUS, ENERGY STAR), and reducing interference with the power grid.
In summary, the core reason for using AC-DC chips in circuits is: AC-DC-AC-DC
The essential requirement of AC-DC-AC-DC is that the heart (chip and circuit) of AC-DC-AC-DC electronic devices only drinks "pure, low-voltage direct current (DC)", while the power grid provides "high-voltage, directional alternating current (AC)". AC-DC chips are essential "translators" and "energy converters".
AC-DC AC-DC-AC-DC safety cornerstone: Through electrical isolation design, AC-DC-AC-DC is a key barrier to ensure the personal safety of users and the protection of internal circuits of equipment from high voltage hazards.
AC-DC AC-DC-AC-DC Efficiency Core: AC-DC-AC-DC achieves efficient (switching power supply technology), precise (voltage regulation), and compact (high power density) power conversion, meeting the strict requirements of modern electronic devices for small size, low heat generation, and high energy efficiency of power supplies.
AC-DC AC-DC-AC-DC regulatory requirements: The PFC and other integrated functions of AC-DC-AC-DC help equipment meet increasingly stringent global energy efficiency and electromagnetic compatibility standards.
Therefore, the AC-DC chip is an indispensable bridge and power source for modern electronic devices to connect to the AC power grid and work on. Without it, the vast majority of electronic devices such as computers, phones, televisions, routers, etc. would not be able to obtain energy from wall sockets.