Dual Redundant Power Control System

Last Updated on Friday, 21 May 2010 13:54 Written by Alison Little Wednesday, 21 April 2010 09:48

For systems where the costs of a failure in the power supply are high, two independent power supplies can be used. The Dual Redundant Power Control System is designed to allow two DC power supplies to be connected to a single supply bus, in a typical dual-redundant power supply application.

The system prevents either power supply from affecting the other, while allowing the two supplies to power-share onto the bus. This is equivalent to a pair of blocking diodes, except that the voltage drop across the system is minimal with very low heat dissipation. The system also allows switching the input channels on or off using a digital input. Currents are measured and feedback is provided in the form of analog voltages. Remote control is also possible, using a dual serial port which allows several systems to be controlled from a single host.

• Input characteristics:
  
  • 20 to 30V DC, up to 25A per channel.  Higher currents are available if required.
• Output:
  
  • As input.
• Settings:
  • Programmable current-trip levels on each input
  • Programmable time delay for re-attempt connection after trip
  • Switch on / off for each input
• Feedback:
  • Input currents on each channel
  • Fault indicator (digital output)
• Serial port:
  
  • A dual serial port is used to implement a serial control and monitoring interface.  Two connections allow daisy-chaining the modules so that a single host can control and monitor up to 15 isolators.  Each isolator serial TX line is held high-impedance so that other devices can use the TX bus.  The protocol allows one global command followed by each isolator reporting feedback in turn.  Each module is identified by a node address so that the host can read data from all modules unambiguously.