Circuit and method for measuring current in a circuit
First Claim
1. An electronic circuit for measuring current in a working circuit, said electronic circuit comprising:
- a first operational amplifier having a positive input, a negative input, and an output connected to at least one in-line amplifier forming a first current path;
a second operational amplifier having a positive input, a negative input, and an output connected to a differential amplifier forming a second current path;
an input terminal connected to the negative inputs of each of the operational amplifiers, said input terminal being connectable to the working circuit to receive an input signal therefrom; and
variable conductance means connected in series between said input terminal and said negative input of said second operational amplifier.
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Accused Products
Abstract
An electronic circuit for measuring current in a working circuit is provided with a first operational amplifier having a positive input, a negative input, and an output connected to at least one in-line amplifier to form a first current path. A second operational amplifier having a positive input, a negative input, and an output connected to a differential amplifier is provided within the circuit to form a second current path. An input terminal is connected to the negative inputs of each of the operational amplifiers to provide a connection between the electronic circuit and the working circuit. A variable conductance component is connected in series between the input terminal and the negative input of the second operational amplifier to control the flow of variable currents through the two current paths.
12 Citations
21 Claims
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1. An electronic circuit for measuring current in a working circuit, said electronic circuit comprising:
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a first operational amplifier having a positive input, a negative input, and an output connected to at least one in-line amplifier forming a first current path; a second operational amplifier having a positive input, a negative input, and an output connected to a differential amplifier forming a second current path; an input terminal connected to the negative inputs of each of the operational amplifiers, said input terminal being connectable to the working circuit to receive an input signal therefrom; and variable conductance means connected in series between said input terminal and said negative input of said second operational amplifier. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A method for measuring current in a working circuit, said method comprising the steps of:
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providing a first current path through a first operational amplifier having a positive input, a negative input, and an output connected to a pair of series connected in-line amplifiers; providing a second current path through a second operational amplifier having a positive input, a negative input, and an output connected to a differential amplifier being series connected to a single in-line amplifier; connecting an input terminal to the negative inputs of said first and second operational amplifiers; directing low level currents from the working circuit into the input terminal; blocking the low level currents from the second current path so that the entire current flow is directed into the first current path; selecting a valid current signal at an output of the series connected pair of in-line amplifiers; and measuring the value of the selected valid current signal. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21)
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Specification