What Is AVS Charging?

Consumers' attention to AVS charging began with the release of the iPhone 17 series and its new charger. But what exactly is "AVS" charging, and is it worth spending more money to buy a charger that supports AVS charging?.

What Does AVS Mean?

Fast charging has become an essential part of everyday life. Whether you are getting ready for work, waiting for a flight, or trying to recharge your phone before heading out, every minute connected to the charger matters.

However, faster charging is not simply about using a charger with a higher wattage. The real challenge is delivering the right amount of power at the right time—without creating unnecessary heat or wasting energy.

AVS stands for Adjustable Voltage Supply. It is a charging mechanism included in newer versions of the USB Power Delivery standard, commonly known as USB PD.

Traditional USB PD chargers normally provide several fixed voltage levels, such as 5V, 9V, 15V or 20V. After the charger and device communicate, the charger selects the closest available voltage.

But the voltage a device needs is not always an exact match for these fixed levels. A phone may require 11.2V, 12.6V or 14.1V during different stages of charging. If the charger can only supply 9V or 15V, the phone must convert the incoming voltage internally.

That extra conversion creates energy loss, and part of that energy becomes heat.

An AVS charger works differently. Instead of relying only on fixed voltage levels, it can adjust its output in 0.1V increments within a supported range. This allows the charger to deliver voltage that more closely matches what the device needs.

In simple terms, AVS helps move part of the voltage-conversion work from the phone to the charger.

How Did AVS Charging Develop?

USB PD charging technology has evolved through several stages.

USB PD 3.0 introduced PPS((Programmable Power Supply), for devices such as smartphones. PPS can adjust voltage in very small 20mV increments and can also regulate current. This makes it possible to change the power supply according to the condition of the battery.

USB PD 3.1 later introduced EPR AVS for high-power devices. EPR stands for Extended Power Range. It supports adjustable voltage from 15V to 48V in 100mV increments, with power levels reaching up to 240W. This makes it suitable for high-performance laptops and other power-demanding equipment.

USB PD 3.2 then extended AVS technology into the standard power range. This version is known as SPR AVS, or Standard Power Range Adjustable Voltage Supply. It generally operates between 9V and 20V, making AVS more suitable for smartphones, tablets and lightweight laptops below 100W.

Why AVS Not PPS?

PPS offers a finer voltage adjustment on paper: 20mV compared with the 100mV, or 0.1V, adjustment used by AVS.

In real charging environments, however, smaller numbers do not always guarantee better results. Cable resistance, connector contact, voltage ripple and transmission loss can all produce variations greater than 20mV. This means that the theoretical precision of PPS may be difficult to maintain throughout the entire charging process.

PPS may also face power limitations at certain voltage levels. When the maximum voltage, current and power limits apply at the same time, the charger may not always reach its advertised maximum output.

AVS takes a more practical approach. Its 100mV adjustment is precise enough to follow the device’s changing needs while remaining stable under real-world conditions. It is designed to balance voltage accuracy, usable power and charging efficiency.

PPS and AVS are not simply competing technologies. They serve different power ranges and charging architectures. The better option ultimately depends on what the charger and connected device are designed to support.

What Are the Benefits of AVS Charging?

The most noticeable difference is that the device temperature is lower when charging.

Because the charger supplies voltage closer to what the battery system needs, the phone performs less internal voltage conversion. This can reduce conversion loss and help keep the device cooler during charging.

Lower heat may also allow the phone to maintain a higher charging rate for longer. A charger may briefly reach an impressive peak wattage, but if the phone becomes too hot, it will quickly reduce the charging power. A smoother temperature profile can be more valuable than a short-lived peak.

AVS may also support better long-term battery care. Heat is one of the factors that accelerates battery ageing. While no charging protocol can prevent natural battery degradation, reducing unnecessary heat can create a more battery-friendly charging environment.

The compatibility across different product categories is also a key advantage. SPR AVS can serve compatible phones, tablets and laptops within the standard power range, while EPR AVS supports more powerful equipment. This brings the industry closer to a unified USB-C charging experience.

Mietubl AVS GaN Wall Charger

Does Every Device Support AVS?

No. Both the charger and the connected device must support the appropriate AVS specification before AVS charging can be activated.

An AVS charger can still charge many devices through conventional USB PD fixed-voltage modes, but those devices will not automatically gain AVS charging simply because they are connected to an AVS-compatible charger.

Software and firmware also matter. A device may contain compatible hardware but not activate a particular charging mode in its current software version. For this reason, AVS compatibility should be confirmed through official specifications or professional protocol testing rather than wattage alone.

The Future of Smarter Fast Charging

AVS represents an important change in how fast charging is understood.

The next stage of charging technology is not only about increasing power from 40W to 60W or from 100W to 240W. It is about supplying power with greater accuracy—fast when time is short, efficient when less power is needed, and stable throughout the charging process.

By dynamically matching voltage to device demand, AVS has the potential to reduce energy loss, control heat and make one USB-C charger useful across more everyday devices.

In other words, AVS does not simply deliver more power. It delivers power in a way that better understands the device in your hand.