Wideband precision current sensor
AssigneeTelefonaktiebolaget LM Ericsson
InventorsDonald Felt Kimball, Joseph L. Archambault, Walter Haley, Lennart Mathe
Life of this patent
Estimating the term…
Abstract
A wideband precision current sensor employs DC-coupled and AC-coupled sensing circuits to generate lower and higher frequency sense signals; which are combined to form a wideband output signal that is proportional to a wideband current of interest. The frequency response of the wideband output signal is substantially flat across a wideband frequency range, 0 to 30 MHz for example, based on matching the frequency response of the DC- and AC-coupled sensing circuits. In an exemplary application, the current sensor provides feedback to a supply voltage (Vdd) amplifier used in RF envelope elimination and restoration (EER) applications.
Claims48
A wideband current sensor comprising:
- a sense element to generate a differential voltage signal proportional to a sensed current;
- a first sensing circuit DC-coupled to the sense element to generate a first signal proportional to lower frequency signal components of the differential voltage signal;
- a second sensing circuit AC-coupled to the sense element to generate a second signal proportional to higher frequency signal components of the differential voltage signal;
- and an output circuit coupled to the first and second sensing circuits to generate a wideband output signal by combining the first and second signals.
A wideband current sensor comprising:
- a sense element to generate a differential sense signal proportional to a sensed current;
- a low-pass sensing circuit DC-coupled to the sense element to generate a first signal by amplifying lower frequency components of the differential sense signal, and wherein the first signal has a defined high frequency roll-off;
- a high-pass sensing circuit AC-coupled to the sense element to generate a second signal by amplifying higher frequency components of the differential sense signal, and wherein the second signal has a defined low frequency roll-off;
- and
- an output circuit to combine the first and second signals and to generate a wideband output signal at an output of the output circuit;
- said defined low frequency roll-off of the low-pass sensing circuit matched to the defined high frequency roll-off of the high-pass sensing circuit such that the wideband output signal exhibits a substantially flat frequency response across a wideband frequency spectrum of interest.
A current sensor comprising:
- a sense element to receive a current and, in response, generate a differential voltage signal;
- a voltage-mode transformer circuit having a first winding coupled in parallel to the sense element such that the differential voltage signal appears across the first winding, and having a second winding to generate a sense signal responsive to the differential voltage signal;
- and
- an output circuit coupled to the second winding of the voltage-mode transformer to generate an output sense signal by amplifying the sense signal generated by the voltage-mode transformer.
A method of sensing a current of interest having wideband frequency components, the method comprising:
- generating a first signal based on sensing lower frequency components of the current, said lower frequency components including DC;
- generating a second signal based on sensing higher frequency components of the current;
- combining the first and second signals to generate a wideband output signal;
- and
- matching frequency-sensitive gains of the first and second signals such that the wideband output signal exhibits a substantially flat frequency response from DC to a maximum frequency of interest.
Dependencies are inferred from the claim text.