Electromagnetic flow sensor interface allowing dc coupling
First Claim
1. 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 be coupled to the first and second inputs to amplify a difference between the first and second inputs to provide a single-ended amplifier output signal including electromagnetic flow sensor information;
conversion circuitry configured to receive the single-ended amplifier output signal and generate a differential signal using the single-ended amplifier output signal; and
an analog-to-digital converter (ADC) circuit configured to convert the differential signal and the single-ended amplifier output signal including the electromagnetic flow sensor information, into digital signals, wherein a dc-coupled signal path is provided from the first and second inputs, through the amplifier circuit, the conversion circuitry, and to the ADC.
3 Assignments
0 Petitions
Accused Products
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.
22 Citations
22 Claims
-
1. 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 be coupled to the first and second inputs to amplify a difference between the first and second inputs to provide a single-ended amplifier output signal including electromagnetic flow sensor information; conversion circuitry configured to receive the single-ended amplifier output signal and generate a differential signal using the single-ended amplifier output signal; and an analog-to-digital converter (ADC) circuit configured to convert the differential signal and the single-ended amplifier output signal including the electromagnetic flow sensor information, into digital signals, wherein a dc-coupled signal path is provided from the first and second inputs, through the amplifier circuit, the conversion circuitry, and to the ADC. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
-
-
13. A method of processing an electromagnetic flow sensor signal, the method comprising:
-
receiving first and second input signals from respective first and second electromagnetic flow sensor electrodes; amplifying a difference between the first and second input signals using an amplifier circuit to provide a single-ended amplified signal; and generating, using conversion circuitry, a differential signal using the single-ended amplifier output signal; and digitizing, using an analog-to-digital converter (ADC) circuit, the differential signal and the single-ended amplified signal to produce digital signals, wherein the receiving and amplifying include providing a dc-coupled signal path through the amplifier circuit to the ADC. - View Dependent Claims (14, 15, 16, 17)
-
-
18. An apparatus for processing an electromagnetic flow sensor signal, the apparatus comprising:
-
means for receiving first and second input signals from respective first and second electromagnetic flow sensor electrodes; means for amplifying a difference between the first and second input signals using an amplifier circuit to provide a single-ended amplified signal; means for generating, using conversion circuitry, a differential signal using the single-ended amplifier output signal; and means for digitizing, using an analog-to-digital converter (ADC) circuit, the differential signal and the single-ended amplified signal to produce digital signals, wherein the means for receiving and means for amplifying include means for providing a dc-coupled signal path through the amplifier circuit to the ADC. - View Dependent Claims (19, 20, 21, 22)
-
Specification