The present invention relates to circuitry comprising: interpolation filter circuitry configured to receive a digital input signal and to output an interpolated digital signal; amplifier circuitry configured to generate an output signal based on the interpolated digital signal; and protection circuitry. The protection circuitry is configured to activate in response to detection of a fault condition at an output of the amplifier circuitry. The circuitry further comprises first detection circuitry configured to output a control signal to disable the protection circuitry on detection of a transient signal at an output of the interpolation filter circuitry that is unrelated to a fault.

The present invention relates to circuitry comprising: interpolation filter circuitry configured to receive a digital input signal and to output an interpolated digital signal; amplifier circuitry configured to generate an output signal based on the interpolated digital signal; and protection circuitry. The protection circuitry is configured to activate in response to detection of a fault condition at an output of the amplifier circuitry. The circuitry further comprises first detection circuitry configured to output a control signal to disable the protection circuitry on detection of a transient signal at an output of the interpolation filter circuitry that is unrelated to a fault.

Apparatus and methods for radio frequency (RF) signal limiting are provided. In certain embodiments, an RF signal limiting system includes a cascade of a front limiter and a biased limiter. Additionally, the front limiter provides an initial amount of limiting to an RF signal, while the biased limiter serves to further limit the RF signal. The biased limiter is adaptively biased such that the amount of limiting provided to the RF signal increases in response to an increase in the RF signal level. Such an RF signal limiting system can be used in a variety of applications, including protecting an input of a low noise amplifier (LNA).

Apparatus and methods for amplifier input-overvoltage protection with low leakage current are provided herein. In certain embodiments, amplifier input circuitry for an amplifier includes a pair of input terminals, a pair of input transistors each having a control input (for instance, a transistor gate), a pair of protection transistors each connected between one of the input terminals and the control input of a corresponding one of the input transistors, and a bidirectional clamp connected between the control inputs of the input transistors. Implementing the amplifier input circuitry in this manner provides a number of advantages including, but not limited to, robust protection against input overvoltage and low input-leakage current.

Apparatus and methods for amplifier input-overvoltage protection with low leakage current are provided herein. In certain embodiments, amplifier input circuitry for an amplifier includes a pair of input terminals, a pair of input transistors each having a control input (for instance, a transistor gate), a pair of protection transistors each connected between one of the input terminals and the control input of a corresponding one of the input transistors, and a bidirectional clamp connected between the control inputs of the input transistors. Implementing the amplifier input circuitry in this manner provides a number of advantages including, but not limited to, robust protection against input overvoltage and low input-leakage current.

Disclosed is an operation amplification circuit and an over-current protection method therefor. The operation amplification circuit comprises: a control unit, configured to generate an output control signal according to an input signal and an output signal; an output unit, configured to generate an output current under control of the output control signal, wherein the output unit comprises an output capacitor which is charged or discharged by the output current to generate the output signal; an over-current protection unit, obtaining a temperature control current according to an operating temperature of the operation amplification circuit, wherein when the operating temperature is greater than or equal to a predetermined temperature, the temperature control current is positively correlated with the operating temperature, and the over-current protection unit adjusts the output control signal according to the temperature control current to limit the output current.

Embodiments of a method and a device are disclosed. In an embodiment, a method for operating a bias controller for an amplifier circuit involves obtaining temperature data corresponding to a temperature of the amplifier circuit, generating a proportional to absolute temperature (PTAT) bias voltage based on a first PTAT slope when the temperature is within a first range of temperatures or a second PTAT slope when the temperature is within a second range of temperatures, wherein the second PTAT slope is greater than the first PTAT slope, and biasing the amplifier circuit based on the generated PTAT bias voltage.

Embodiments of a method and a device are disclosed. In an embodiment, a method for operating a bias controller for an amplifier circuit involves obtaining temperature data corresponding to a temperature of the amplifier circuit, generating a proportional to absolute temperature (PTAT) bias voltage based on a first PTAT slope when the temperature is within a first range of temperatures or a second PTAT slope when the temperature is within a second range of temperatures, wherein the second PTAT slope is greater than the first PTAT slope, and biasing the amplifier circuit based on the generated PTAT bias voltage.

An operational amplifier includes a first output transistor and a second output transistor connected in series between two power nodes, the second output transistor having a semiconductor type opposite to the first output transistor, the first output transistor and the second output transistor being electrically coupled at an output node, and gates of the first output transistor and the second output transistor being connected to a first drive node and a second drive node respectively; and a decoupling capacitor circuit electrically connected between the first drive node and the second drive node.

An operational amplifier includes a first output transistor and a second output transistor connected in series between two power nodes, the second output transistor having a semiconductor type opposite to the first output transistor, the first output transistor and the second output transistor being electrically coupled at an output node, and gates of the first output transistor and the second output transistor being connected to a first drive node and a second drive node respectively; and a decoupling capacitor circuit electrically connected between the first drive node and the second drive node.