Description

STWBC-EP

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DocID030747 Rev 1

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Description

The STWBC-EP is the digital controller for the wireless battery charger (WBC) transmitters

(TX) from STMicroelectronics optimized for Extended Power Profile (EPP) Wireless Power

Consortium (WPC) 1.2 certified applications up to 15 W.

It offers the most flexible and efficient solution for controlling the power transfer to a receiver

(RX) in WBC-enabled applications such as smartphones, tablets and other battery-powered

devices that use the electromagnetic induction for recharging.

The TX is responsible for controlling the transmitting coil and generating the correct amount

of power requested by the RX. The RX continuously provides the transmitter with the correct

power level requested, by modulating the transmitter carrier through the controlled resistive

or capacitive load. Generating the correct amount of power ensures the highest level of end-

to-end efficiency due to reduced energy losses. It also helps maintaining a lower operational

temperature.

The TX can adapt to the amount of energy transferred by the coil by modulating the

frequency, duty cycle or amplitude of the PWM voltage on the transmitting coil.

The STWBC-EP is capable of bidirectional communication with the RX as specified by the

WPC 1.2 protocol.

Figure 1. Wireless charging system description

The STWBC-EP firmware is specifically designed to take advantage of the hardware to

monitor and control the correct wireless charging operations.