A clipping detector circuit includes a timer circuit and a counter circuit. The timer circuit is configured to monitor a time period elapsing since a last occurrence of an edge in a PWM signal, assert a first signal when the time period elapses, and de-assert the first signal and reset the time period as a result of an edge occurring in the PWM signal. The counter circuit is configured to determine a number of pulses in the PWM signal since the last de-assertion of the first signal, and assert a second signal when the number of pulses in the PWM signal since the last de-assertion of the first signal reaches m pulses. The clipping detector circuit is configured to generate a clipping detection signal indicative of whether the pulse-width modulated signal is clipped or not as a function of the first signal and the second signal.

Systems and methods are provided for dynamically biasing power amplifiers. In particular, dynamic biasing of a power amplifier may be controlled, with the controlling comprising receiving an input signal that is to be amplified; processing the input signal; generating based on said processing of the input signal input signal, a plurality of control signals comprising at least one biasing control signal; and applying the plurality of control signals to one or more control elements that are used in driving and/or control of the power amplifier. The one or more control elements may comprise at least one biasing component that adjusts biasing applied to power amplifier.

According to one embodiment, a clipping state detecting circuit includes: a zero-cross detection circuit that detects a zero-cross point of an input signal; an output circuit that converts the input signal into a PWM signal; a clip detection circuit that detects a state in which an output of the output circuit is clipped; and a control circuit that determines a state is a clipping state when a clip time of the output of the output circuit satisfies a condition of a threshold value set in advance with respect to a non-clip time.

A trans-impedance amplifier (TIA) includes a first circuit, a second circuit, and a third circuit. Both the first circuit and the second circuit are coupled to a current source, an operational amplifier, and the third circuit. The first circuit is configured to receive a first current, provide a third voltage to the third circuit, perform shape filtering on the first current, and convert the shape filtered first current to a first voltage for output. The second circuit is configured to receive a second current, provide a fourth voltage to the third circuit, perform shape filtering on the second current, and convert the shape filtered second current to a second voltage for output. The third circuit is configured to cooperate with the first circuit and the second circuit in performing shape filtering. The operational amplifier is configured to provide a small-signal virtual ground point to the first circuit.

A logarithmic detector amplifying (LDA) system is provided for use as a high sensitivity receive booster or replacement for a low noise amplifier in a receive chain of a communication device. The LDA system may include an amplifying circuit configured to receive an input signal having a first frequency and generate an oscillation based on the input signal, a sampling circuit coupled to the amplifying circuit and configured to terminate the oscillation based on a predetermined threshold to generate a series of modulated pulses, and one or more resonant circuits including at least one variable capacitor, coupled with the amplifying circuit and configured to establish a frequency of operation and generate an output signal having a second frequency being substantially the same as the first frequency, with the operating frequency being adjustable in response to baseband information received from the system via the one or more variable capacitors.

A trans-impedance amplifier (TIA) includes a first circuit, a second circuit, and a third circuit. Both the first circuit and the second circuit are coupled to a current source, an operational amplifier, and the third circuit. The first circuit is configured to receive a first current, provide a third voltage to the third circuit, perform shape filtering on the first current, and convert the shape filtered first current to a first voltage for output. The second circuit is configured to receive a second current, provide a fourth voltage to the third circuit, perform shape filtering on the second current, and convert the shape filtered second current to a second voltage for output. The third circuit is configured to cooperate with the first circuit and the second circuit in performing shape filtering. The operational amplifier is configured to provide a small-signal virtual ground point to the first circuit.

According to one embodiment, a clipping state detecting circuit includes: a zero-cross detection circuit that detects a zero-cross point of an input signal; an output circuit that converts the input signal into a PWM signal; a clip detection circuit that detects a state in which an output of the output circuit is clipped; and a control circuit that determines a state is a clipping state when a clip time of the output of the output circuit satisfies a condition of a threshold value set in advance with respect to a non-clip time.

Preventing RF signal distortion and signal error producing memory events in a Radio Frequency (RF) power amplifier (RFPA). An element, disposed prior to the Radio Frequency (RF) power amplifier (RFPA) in a signal path of a RF signal input to the RFPA, may enforce a maximum allowable amplitude in a high PAPR instantaneous high peak of the RF signal. An element may also increase or supplement a bias of the Radio Frequency (RF) power amplifier (RFPA) when a high PAPR instantaneous high peak is detected in the RF signal prior to receipt by the RFPA. Additionally, a first element operable detects when an instantaneous output voltage of the Radio Frequency (RF) power amplifier (RFPA) is below a predetermined voltage, and in response, a second element supplies additional current to prevent the output voltage of the RFPA from falling below a predetermined threshold voltage.

An integrated circuit, comprising an amplifier comprising a pair of inputs configured to receive a differential signal, a first resistor, a second resistor, wherein the first resistor and the second resistor are coupled in series with each other and coupled to a first input of the pair of inputs, a third resistor, a fourth resistor, wherein the third resistor and the fourth resistor are coupled in series with each other and coupled to a second input of the pair of inputs, and a first capacitor comprising a first end coupled to a first point between the first resistor and the second resistor, and a second end coupled to a second point between the third resistor and the fourth resistor, a second capacitor disposed between the first input and an output of the amplifier; and a third capacitor disposed between the second input and the output.

Preventing RF signal distortion and signal error producing memory events in a Radio Frequency (RF) power amplifier (RFPA). An element, disposed prior to the Radio Frequency (RF) power amplifier (RFPA) in a signal path of a RF signal input to the RFPA, may enforce a maximum allowable amplitude in a high PAPR instantaneous high peak of the RF signal. An element may also increase or supplement a bias of the Radio Frequency (RF) power amplifier (RFPA) when a high PAPR instantaneous high peak is detected in the RF signal prior to receipt by the RFPA. Additionally, a first element operable detects when an instantaneous output voltage of the Radio Frequency (RF) power amplifier (RFPA) is below a predetermined voltage, and in response, a second element supplies additional current to prevent the output voltage of the RFPA from falling below a predetermined threshold voltage.