An amplifier may include a main signal path having a plurality of stages compensated by feedback elements, the plurality of stages comprising an output stage configured to receive electrical energy from a power supply and an auxiliary path independent of the main signal path and comprising an output stage compensation circuit configured to generate a compensation current proportional to noise present in the power supply and apply the compensation current to cancel a power supply-induced current present in at least one of the feedback elements.

An amplifier circuits inductive/magnetic sensor interface can include a main signal path including one or more amplifiers configured to receive an input signal and to produce an output signal based on the input signal. The input signal may include a square-wave demodulated signal having an associated modulation frequency and an undesired frequency component at twice the modulation frequency of the square-wave demodulated signal. The amplifier circuit may include a gain feedback loop configured to set a gain of the amplifier circuit. The amplifier circuit may include a ripple reduction feedback loop configured to receive an intermediate signal on the main signal path and extract the undesired frequency component of the intermediate signal to produce a filtered version of the intermediate signal and provide the filtered version of the intermediate signal to the main signal path.

A signal amplifier includes one or more driver stage amplifiers and a power stage amplifier. The one or more driver stage amplifiers are connected in series. The one or more driver stage amplifiers and the power stage amplifier are connected to the same power supply, such that each of the at least one driver stage amplifier forms a loop with the power stage amplifier. The signal amplifier can further include a wave trap unit configured to block an oscillation frequency in the loop. One terminal of the wave trap unit is connected to the loop. The other terminal of the wave trap unit is grounded.

The present invention relates to an amplification device (10) of an input signal comprising: a first amplification stage (12), a second amplification stage (14), each amplification stage (12, 14) comprising: a switching circuit (22), the switching circuit (22) being able to generate, as output (22A, 22B), a switched signal having at least two states, and an inductive element (24) able to smooth the switched signal to obtain a smoothed signal (I1, I3), the smoothed signal (I1, I3) having a useful component and a stray component.

The amplification device (10) further comprises a compensation circuit (16), for each amplification stage (12, 14), able to generate a compensation signal (I2, I4) of the stray component of the smoothed signal (I1, I3) generated in the inductive element (24) of the corresponding amplification stage (12, 14).

A six phase capacitively coupled chopper amplifier. Two phases provide a zeroing phase to zero the feedback capacitors and set the input common mode value. Two phases provide a passive transfer of an input charge from the input capacitors to the zeroed feedback capacitors. The final two phases are chopping and amplification phases. The zeroing phases address the input common mode without the need for biasing resistors. The passive transfer phases resolve the glitching that occurs if the feedback capacitors have to be recharged on each cycle of the chopping clock. Resolving the glitching and the charge time allows the frequency of the amplifier to increase.

Chopper amplifiers with high pass filters for suppressing chopping ripple are provided herein. In certain embodiments, a chopper amplifier includes an input chopping circuit, an amplification circuit, a low frequency content detection circuit, and an output chopping circuit electrically connected in a cascade. The low frequency content detection circuit operates in combination with a transconductance or other gain circuit as a high pass filter that filters input offset voltage and/or low frequency noise of the amplification circuit, thereby suppressing output chopping ripple from arising.

Resistor mismatch may be digitally compensated based on a known resistor mismatch, power supply information, and/or other operating parameters of the amplifier. The digital compensation may be applied to the digital input signal before conversion for processing and amplification in the analog domain. An amplifier with digital compensation for resistor mismatch may be used in a class-D amplifier with a closed loop and feedforward feedback. A class-D or other amplifier with digital compensation may be integrated with electronic devices such as mobile phones.

A capacitive-coupled chopper instrumentation amplifier includes a first chopper, a first gain stage, a capacitive isolation stage electrically coupled between inputs of the first gain stage and the first chopper, a second gain stage, a second chopper electrically coupled between outputs of the first gain stage and inputs of the second gain stage, clamping circuitry electrically coupled between the inputs of the first gain stage and a reference voltage rail, and a controller. The controller is configured to (a) detect a change in a first common-mode voltage exceeding a threshold value, the first common-mode voltage being a common-mode voltage at the inputs of the amplifier, and (b) in response to detecting the change in the first common-mode voltage exceeding the threshold value, cause the clamping circuitry to clamp the inputs of the first gain stage to the reference voltage rail.

Resistor mismatch may be digitally compensated based on a known resistor mismatch, power supply information, and/or other operating parameters of the amplifier. The digital compensation may be applied to the digital input signal before conversion for processing and amplification in the analog domain. An amplifier with digital compensation for resistor mismatch may be used in a class-D amplifier with a closed loop and feedforward feedback. A class-D or other amplifier with digital compensation may be integrated with electronic devices such as mobile phones.

Embodiments relate to a chopped amplifier system where a ripple reduction filter placed outside of a main signal path is disclosed. The chopped amplifier system includes a chopped amplifier having an input terminal and an output terminal, where the input terminal receives an input signal and the output terminal provides an output signal including a ripple that is based on an offset voltage of the chopped amplifier. The ripple reduction filter is placed in a feedback loop path that receives a portion of the chopped amplifier's output signal and provides a feedback signal to the chopped amplifier that reduces the ripple at the output of the chopped amplifier. The ripple reduction filter includes a digital controller and other circuits that can handle large disturbances such as large signal slew rate events and large common-mode steps without reducing the effectiveness of the ripple reduction filter in reducing the ripple.