Improved interface circuit for use in multi-split air conditioning systems

摘要

An interface circuit for producing a single DC control voltage in response to any one of a plurality of different AC control voltages. The interface circuit includes a plurality of AC inputs for receiving different respective AC control voltages and a DC output. A comparator controls the voltage at the DC output in accordance with a reference voltage and a DC control voltage. An AC to DC converter includes a scaling network which generates the same DC control voltage without reference to which one of the AC inputs is receiving its respective AC control voltage. <IMAGE>