A dynamically stabilizable amplifier drives an output current into an RLC load. A driver stage generates the output current, and a control circuit compares a current level of the amplifier output with a threshold and selectively enables a stabilizing resistor (to selectively shunt the load or dampen in series with the load, depending on RLC load type) at the driver stage output based on the comparison so that the amplifier is stable across a range of the output current level. The control circuit disables the resistor when the output current is above the highest threshold and enables it when below. The control circuit may control the resistor to have one of multiple resistance values based on a comparison with multiple thresholds. The output current level may be determined by replicating the output current level or by an input current level that sets the output current level independent of the load.

Disclosed herein are transconductance circuits, as well as related methods and devices. In some embodiments, a transconductance circuit may include an amplifier having a first input coupled to a voltage input of the transconductance circuit, and a switch coupled between an output of the amplifier and a second input of the amplifier.

A class-D amplifier with multiple “nested” levels of feedback. The class-D amplifier surrounds an inner feedback loop, which takes the output of a switching amplifier and corrects for errors generated across the switching amplifier, with additional feedback loops that also take the output of the switching amplifier.

An LNA having a plurality of paths, each of which can be controlled independently to achieve a gain mode. Each path includes at least an input FET and an output FET coupled in series. A gate of the output FET is controlled to set the gain of the LNA. Signals to be amplified are applied to the gate of the input FET. Additional stacked FETs are provided in series between the input FET and the output FET.

A switched-capacitor amplifier circuit includes multiple switched-capacitor networks, an amplifier, and multiple reset circuits. The switched-capacitor networks are configured to receive respective input voltages during a sampling phase, and generate sampled voltages. During an amplification phase, the amplifier is coupled with the switched-capacitor networks, and is configured to receive the sampled voltages. The amplifier is further configured to generate output voltages. During the sampling phase, the amplifier is coupled with the reset circuits, and is further configured to receive divided voltages such that the amplifier is reset. The reset circuits are configured to receive and provide a common-mode voltage and the output voltages to the amplifier. The divided voltages are generated based on the common-mode voltage and the output voltages. Each reset circuit includes at least one of a resistor and a capacitor.

Methods and devices used in mobile receiver front end to support multiple paths and multiple frequency bands are described. The presented devices and methods provide benefits of scalability, frequency band agility, as well as size reduction by using one low noise amplifier per simultaneous outputs. Based on the disclosed teachings, variable gain amplification of multiband signals is also presented.

A circuit arrangement comprises a first input node, a first output node, a sampling capacitor means and a first switching means being switchable between a first switching state and a second switching state. The first switching means is coupled to the sampling capacitor means, the first input node and the first output node in such a way that the sampling capacitor means is conductively connected to the first input node and disconnected from the first output node in the first switching state and the sampling capacitor means is disconnected from the first input node and conductively connected to the first output node in the second switching state. A first charge-storing element is coupled via a second switching means to the first input node in such a way that the charge-storing element is charged in the first switching state and discharged in the second switching state, thereby at least partly compensating current flow for charging the sampling capacitor means in the first switching state.

A circuit for use in a system that includes a detector, wherein the circuit comprises an input terminal to receive a detector signal from the detector external to the circuit, the detector signal to include an error charge corresponding to a leakage current. The circuit further comprises an amplifier coupled to the input terminal to receive input signals corresponding to the detector signal, including the error charge applied to an input of the amplifier. The circuit further comprises a feedback path coupled across the amplifier, wherein the feedback path comprises a first switch coupled across a leakage resistor and to a leakage capacitor for discharging a feedback compensation charge from the leakage capacitor and onto the input of the amplifier to substantially cancel the error charge.

A dynamically stabilizable amplifier drives an output current into an RLC load. A driver stage generates the output current, and a control circuit compares a current level of the amplifier output with a threshold and selectively enables a stabilizing resistor (to selectively shunt the load or dampen in series with the load, depending on RLC load type) at the driver stage output based on the comparison so that the amplifier is stable across a range of the output current level. The control circuit disables the resistor when the output current is above the highest threshold and enables it when below. The control circuit may control the resistor to have one of multiple resistance values based on a comparison with multiple thresholds. The output current level may be determined by replicating the output current level or by an input current level that sets the output current level independent of the load.

In a general aspect, a circuit can include an input circuit configured to receive an input signal, and an amplifier circuit coupled with the input circuit. The amplifier circuit can include an amplifier, and first and second feedback paths. The first feedback path can be from a positive output to a negative input of the amplifier, and the second feedback path can be from a negative output to a positive input of the first amplifier. The circuit can also include a loop circuit configured to provide a local feedback loop for the first amplifier and configured to control current flow into the positive input of the first amplifier and current flow into the negative input of the first amplifier. The circuit can also include a control circuit that is configured to enable the loop circuit in response to a magnitude of the input signal exceeding a threshold.