AVS in the USB Power Delivery standard adjusts the output voltage of the charging adapter according to the demand of the compatible device. This feature, which is also encountered in the fast charging conditions of new iPhone models, shows that just looking at the wattage is not enough when choosing an adapter. In addition, AVS support does not constitute an independent technology that charges every phone at the same speed.
The abbreviation AVS comes from the name Adjustable Voltage Supply and refers to adjustable voltage source. The device, powered via USB-C connection, can request intermediate voltage within the range offered by the adapter. Thus, power transfer is not limited to predetermined fixed output levels.
USB-IF explains that within its extended power range, this setting extends from 15 volts to the highest fixed voltage the adapter supports. The agency also associates the 28, 36, and 48 volt levels with the power classes of 140, 180, and 240 watts, respectively. However, the upper limit of 240 watts does not mean that every adapter marked AVS offers this power.
The device, adapter and cable together determine the power transfer. The Power Delivery technical presentation of USB-IF explains that the source device first reports its capacity, and the receiving device then transmits the power request. Therefore, a higher capacity adapter does not force the connected device to transfer the unwanted power on its own.
AVS support gains meaning with cable and device
USB Power Delivery can deliver different power profiles over the same physical connection. In addition, the shape of the USB-C plug does not alone explain the current the cable will carry or the charging protocol supported by the device. Especially for high power use, it is necessary to check the capacity of the cable from the product information.
PPS is another programmable power approach in the USB Power Delivery family. USB-IF states that in the PPS stream, the device regularly renews its voltage and current demand, and the adapter transmits operating status information. Instead of accepting the names of two features as the same, it is necessary to take the supported profiles in the technical documentation of the device as basis.
On the other hand, AVS does not promise a constant temperature drop or increase in battery life in all charging processes. Charging time and temperature depend on the conditions of use as well as the management of the device. USB-IF’s current documentation library lists USB PD 3.2 documentation; When choosing a product, the compatibility and power profiles declared by the manufacturer are decisive.