What is the voltage of wireless charging coils?
The voltage of wireless charging coils can vary depending on the specific standard or technology being used. Here are some common wireless charging standards and their associated coil voltages:
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Qi (pronounced “chee”) Standard: This is the most common wireless charging standard for consumer electronics like smartphones. The Qi standard specifies different power classes, and the coil voltage can be different for each class:
- Low Power (less than 5 W): The coil voltage is typically around 3.3 to 4.2 volts.
- Medium Power (5 W to 15 W): The coil voltage is usually around 5 to 12 volts.
- High Power (15 W to 30 W or more): The coil voltage can range from 12 to 20 volts or higher.
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AirFuel Alliance (formerly known as Rezence): This standard uses resonant inductive coupling and can support higher power levels for applications like laptops and kitchen appliances. The coil voltage can range from 19 volts to 32 volts or more, depending on the power requirements.
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WiTricity (also based on resonant inductive coupling): This technology can support a wide range of power levels, and the coil voltage can vary accordingly, typically ranging from 6.6 volts to 20 volts or higher.
It’s important to note that the voltage across the wireless charging coils is not the final output voltage that charges the device. The receiver circuit in the device will convert the coil’s AC voltage to the appropriate DC voltage needed to charge the battery.