Remote Electrical Tilt Unit RET

The Remote Electrical Tilt Unit RET allows for accurate control of antenna tilt eliminating tower climbs, allowing the tilt to be adjusted remotely from the Base station/network control centre and only in a matter of minutes. This allows for timely and accurate response to changing capacity requirements of the network.


 
The solution comprises of a Motor driven Antenna, with communication to the BTS via port RS-485 and a microprocessor that controls the communication and performs supervisory functions.

Most of the RET systems use the AISG protocol (Antenna Interface Standard Group.
 
The TI MSP430 processor family is the perfect choice of processor for performing all monitoring and  functions.

Integrated high performance analog blocks provide a high degree of accuracy for applications requiring precise measurement and monitoring.

Featuring High Performance, Flexibility, and a variety of peripheral options, the MSP430 allows applications to get implemented faster, using lesser code and power at lower cost.

 
The Integrated Stepper Motor Driver solution has two H-bridge drivers, as well as microstepping indexer logic to control a stepper motor.

The output driver block for each consists of N-channel power MOSFETs configured as full H-bridges to drive the motor windings.

A simple step/direction interface allows easy interfacing to controller circuits. Pins allow configuration of the motor in full-step, half-step, quarter-step, or eighth-step modes.

Decay mode and PWM off time are programmable. Internal shutdown functions are provided for over current protection, short circuit protection, under-voltage lockout and over temperature.
 
TI has a complete power solution-Linear regulators, Step-down regulators and DC/DC converters for the RET unit that can step down the supply rail to any intermediate level for powering all other chips on board.
 
In-rush limiting is implemented to limit the in-rush current going to the board at startup.

The TI Hotswap controller can be used to smoothly control the voltage and current ramp up.