US 10,480,970 B2 · Electromagnetic flow sensor interface allowing differential dc coupling

Abstract

An interface circuit to an electromagnetic flow sensor is described. In an example, it can provide a DC coupled signal path from the electromagnetic flow sensor to an analog-to-digital converter (ADC) circuit. Examples with differential and pseudo-differential signal paths are described. Examples providing DC offset or low frequency noise compensation or cancellation are described. High input impedance examples are described. Coil excitation circuits are described, such as can provide on-chip inductive isolation between signal inputs and signal outputs. A switched mode power supply can be used to actively manage a bias voltage of an H-Bridge, such as to boost the current provided by the H-Bridge to the sensor coil during select time periods, such as during phase shift time periods of the coil, which can help reduce or minimize transient noise during such time periods.

Claims20

Dependent claims

An apparatus for processing an electromagnetic flow sensor signal;

the apparatus comprising:
first and second inputs configured to be respectively coupled to first and second electromagnetic flow sensor electrodes;
an amplifier circuit configured to:
apply a gain to a difference between the first and second inputs to amplify the difference based on a resistance coupled to the amplifier circuit;
and
output the amplified difference;
and
an analog-to-digital converter (ADC) circuit configured to receive the amplified difference from the amplifier circuit and to convert the amplified difference into a digital signal;
wherein a dc-coupled signal path is provided from the first and second inputs, through the amplifier, to the ADC.

6 more elements

Dependencies are inferred from the claim text.

Electromagnetic flow sensor interface allowing differential dc coupling

Life of this patent

Electromagnetic flow sensor interface allowing differential dc coupling

Life of this patent

Abstract

Claims20