In latest generation of car exterior mirrors, the number of embedded functions has dramatically increased: the side repeater, the directional/flasher, the door’s outside lights, the defroster, and the foldingin and adjustment of the mirror to name a few. On top of

those features, the electro-chromatic control (to automatically darken the mirror) has recently been adopted to solve the problem of the reflecting light dazzling the driver. The electro–chromatic (EC) glass is a capacitive-resistive equivalent load and its control requires a sophisticated strategy.

ST provide a dedicated solution, for the mechatronic exterior mirror, integrating in a single device all actuators drivers required to implement all the functions described above. The device, integrating also a voltage regulator and a LIN tranceiver, is able to control via an integrated SPI  the wing mirror movement, mirror turn indicator light, defroster, some lamps and also an electro chromic mirror . The SPI controls all operation modes (forward, reverse, brake and high-impedance) and provides all the diagnostic information.

With such solutions a module can be completed with a microcontroller  and a discrete low current MOSFET required for charging/discharging the electrochromic glass.

 

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