kicad_xfer-sw_interface

Pulse Latching RF Transfer Switch Interface for VTGS SX-Band System.
V1, Rev- Designed to Control a Single Relcomm RTS-TS3AB-I Transfer Switch.

The VTGS SX-Band System uses four RTS-TS3AB-I transfer switches to set the RF receive path to an X310 USRP with Dual UBX-160s. Two transfer switches select the receive band for the USRP Band A RX2 port and Band B RX2 port (S or X). Two transfer switches select the receive polarization for the selected band (RHCP or LHCP).

Relcomm RTS-TS3AB-I Transfer Switch Description

See linked product for full datasheet and feature list. Features listed below are the pertinent features for the control circuit.

• Pulse Latching, short duration pulse on coil sets latched position.
• 28V Coil Voltage, common negative, pulse on positive side of Coil 1 or 2.
• Indicator feedback, 1P2T switch indicates position.

V1, Rev- Circuit Design Features

This version / revision submitted to osh park for PCB fab on 20220118.

• TTL Level Control from MCU (+5V / +3V3)
• TTL Level Feedback for MCU (+5V / +3V3)
• Optically Isolated Control (ILD207T)
• LED Current Position Indicator (POS1 - RED, POS2 - BLUE)
• LED Set Position Indicator (pulsed, both green)
• Relay Coil Control via dual W6PQL based FET Switch circuits

Credit where its due:

The transfer switches in this design are controlled by a High Current DC Switch based on the W6PQL design. The specific P-Channel MOSFET is modified for smaller form factor and lower current draw. The DISABLE feature is not needed and not implemented.