Circuit arrangement comprising input circuits to find a power output sum for application in multi-phase electricity meters

A circuit arrangement for summing power outputs for use in a multi-phase electricity meter, said circuit arrangement comprising:

• a plurality of inputs circuits arranged in a sequence, each of said input circuits comprising an input converter, a multiplier connected to said input converter, and a voltage-to-frequency converter connected to said multiplier,
• starting at least with the second input circuit in said sequence, each of said input circuits comprising an adder having a first input means connected to the voltage-to-frequency converter of the corresponding input circuit, a second input means connected to an output of the preceding input circuit in said sequence, and an output which forms an output of the corresponding input circuit.
• wherein
• each voltage-to-frequency converter is provided with a first output for positive power and a second output for negative power,
• the first input means of each adder comprises first and second inputs,
• the second input means of each adder comprises first and second inputs,
• each adder has first and second outputs, one for positive power and one for negative power, said first and second outputs of each adder forming first and second outputs of the corresponding input circuit,
• said first and second outputs of each frequency converter being connected, starting at least with the second input circuit in said sequence, to the first and second inputs of the first input means of the corresponding adder, and
• said first and second inputs of the second input means of each adder being connected to a position power output and a negative power output of the preceding input circuit in said sequence.