“Enhancements to the TB6865FG power transmitter and TC7763WBG receiver chipset enable faster wireless charging of mobile devices,” said the firm.
The design is compliant to the Qi v1.1 specification for 3.5W power transfer, intended to be compliant to v1.1 for 5W transfer, and includes foreign object detection.
Wireless charging has been dogged with the need to accurate align the object to be charged with the charger coil.
TB6865FG (14x14mm LQFP-100) includes a microcontroller that can drive four external mosfet H-bridges for four coils – allowing two devices to be charged with some position flexibility.
When discussing the same transmit chip with the similar TB6860WBG receiver, of two coils per device charging Toshiba said: “The position of a mobile device is detected by the TB6865FG and only one of the coils is energised for charging, allowing product freedom of placement. As a result, end users can place a Qi-capable mobile product on a Qi-compliant charging surface and achieve up to 74% efficiency across a majority of the charging area. Rated efficiency can be achieved except at the four edges of the charging pad and within few millimetres above the charging pad.”
The efficiency of wireless charging is still significantly less than that possible with wired charging, and stand-by power is higher.
TC7763WBG (2.4×3.7×0.5mm WCSP-28) has modulation and control circuitry with a rectifier power pick-up, built-in linear regulator, and circuit protection.
Another chip, TC7761WBG, is certified for 3.5W.