A receiver front end having low noise amplifiers (LNAs) is disclosed herein. A cascode having a common source configured input FET and a common gate configured output FET can be turned on or off using the gate of the output FET. A first switch is provided that allows a connection to be either established or broken between the source terminal of the input FET of each LNA. A drain switch is provided between the drain terminals of input FETs to place the input FETs in parallel. This increases the g.sub.m of the input stage of the amplifier, thus improving the noise figure of the amplifier.

An amplifier-resident device for protecting amplifiers and loudspeakers from shock transient audio signals from dropped microphones that may use either an amplifier control signal from the microphone or a sequential sampling of the incoming audio (optionally switchable) to determine if a microphone drop, or other shock transient, is occurring. If a shock transient is occurring, the device blocks audio signal access to the amplifier. The audio signal goes through a delay line to allow processing time for detecting a shock transient and switching the shock transient audio signal out of the path to the amplifier. The delay may be variable. The device may be integral to the amplifier or may plug into a microphone jack of the amplifier, allowing use with legacy amplifiers. In an embodiment, the device may store safe, predetermined audio signals to send to the amplifier during, and in place of, a shock transient.

An apparatus comprising an amplifier comprising an input, a capacitor having a capacitor first side and a capacitor second side, wherein the capacitor first side is coupled to the input, a switch having a switch first side and a switch second side, wherein the switch first side is coupled to the capacitor second side, and a transistor having a transistor gate, and a transistor source, wherein the transistor gate is coupled to the input and the capacitor first side, wherein the transistor source is coupled to the switch second side and wherein the switch is positioned directly between the capacitor second side and the transistor source.

A distributed amplification device with p inputs, p outputs, p amplification paths comprises a redundant reservoir of n amplifiers including n-p back-up amplifiers, an input redundancy ring and an output redundancy ring formed by rotary switches, the input and output redundancy rings sharing the same technology. The internal amplification pathways associated with the n-p back-up amplifiers frame in an interlaced manner the internal amplification pathways associated with the p nominal amplifiers and the amplification paths of the routing configurations each pass through at least five rotary switches. The input and output redundancy rings are topologically and geometrically configured and the family of the routing configurations is chosen such that the electrical lengths of all the paths of one and the same routing configuration of the family are equal.

Apparatus and methods for digitally-assisted feedback offset correction are provided herein. In certain configurations, an amplifier includes amplification circuitry for providing amplification to an input signal and chopping circuitry for compensating for an input offset voltage of the amplifier. Additionally, the amplifier further includes a digitally-assisted feedback offset correction circuit, which includes a chopping ripple detection circuit, a feedback-path chopping circuit, a digital correction control circuit, and an offset correction circuit. The chopping ripple detection circuit generates a detected ripple signal based on detecting an output ripple of the amplifier. Additionally, the feedback-path chopping circuit demodulates the detected ripple signal using the amplifier's chopping clock signal. The digital correction control circuit receives the demodulated ripple signal, which the digital correction control circuit uses to control a value of a digital offset control signal that controls an amount of input offset correction provided by the offset correction circuit.

Methods and apparatus for providing amplifier protection for a radio frequency (RF) front-end circuit. An example RF front-end circuit generally includes an amplifier with a gain, a first sensor configured to sense a first power (or voltage) of a first node coupled to an input of the amplifier, a second sensor configured to sense a second power (or voltage) of a second node coupled to an output of the amplifier, and logic coupled to the first and second sensors. The logic is generally configured to determine that the second power (or voltage) is outside a range based on the gain and the first power (or voltage) and to take an action to protect the amplifier based on the determination. By utilizing the techniques and apparatus described herein, protection can be provided to the amplifier(s) in an RF front-end circuit without significantly impacting the performance of the RF front-end circuit.

There is provided an operational amplifier which is operable as well when an operating voltage decreases without creating a range where a circuit would not operate or reducing circuit gain. High-pass filters 102-105 provide output signals therefrom to bias-set input nodes of differential amplifiers Gm1-Gm4 to a potential within a common-mode range in which the respective differential amplifiers Gm1-Gm4 are operable. In this manner, the respective differential amplifiers Gm1-Gm4 can be operated effectively regardless of the possible decrease in a supply voltage, enabling normal amplifying operation. In addition, reduction in gain due to the reduced operational voltage is avoided. Therefore, it is preferably applicable to the application where digital and analog circuits are loaded together on the same IC chip. When a high-pass filter is required at each input side of two- or more-stage differential amplifiers, a phase compensation method utilizing multiple paths is provided for a lower range of a phase margin created at the low frequency side, enabling normal amplitude operation.

Provided is a redundant amplifier, including: a first switch for connecting, on a one-to-one basis, inputs P1 to Pm to m of outputs Q1 to Qn, where m and n are natural numbers and m<n is satisfied; a second switch for connecting, on a one-to-one basis, m of inputs R1 to Rn to m outputs S1 to Sm; and amplifiers A1 to An connected on a one-to-one basis between the outputs Q1 to Qn and the inputs R1 to Rn. Signal paths L1 to Lm are formed in accordance with a connection state between an input and an output of each of the first switch and the second switch, the signal paths L1 to Lm connecting the input P1 and the output S1, the input P2 and the output S2, . . . , and the input Pm and the output Sm, respectively, via any one of the amplifiers A1 to An. The connection state has at least two types in which the signal paths L1 to Lm each have the same length.

One example includes an OP-AMP circuit system. The system includes a signal amplification path comprising a signal amplification path comprising a signal amplifier and an output stage. The signal amplification path can be configured to amplify an input voltage received at an input to provide an output voltage via the output stage. The system also includes an offset-reduction path coupled to the input of the signal amplification path and to an output of the signal amplifier. The offset-reduction path includes a transconductance amplifier and at least one chopper that are configured to mitigate noise in the signal amplification path and a noise-filtering feedback path configured to provide chopper feedback with respect to an offset voltage associated with the offset-reduction path, the noise-filtering feedback path comprising a feedback path input coupled to the input of the transconductance amplifier via a resistor.

A digital power amplifier to drive an RFID antenna with an antenna signal of a substantial sinusoidal output current. This digital power amplifier includes a switching element built to switch at least one of the 2*W driver blocks from a contributing mode into a none-contributing mode, in which none-contributing mode the driver block does not contribute with an increment of charge to the output current to adjust the amplitude and/or the waveform of the output signal.