A power amplifier includes an over-current protection loop and/or an over-voltage protection loop to assist in preventing operation outside a safe operation zone. In a further exemplary aspect, triggering of the over-current protection loop adjusts a threshold voltage for the over-voltage protection loop. In further exemplary aspects, the over-current protection loop may adjust not only a bias regulator, but also provide an auxiliary control signal that further limits signals reaching the power amplifier. In still further exemplary aspects, the over-voltage protection loop may operate independently of the over-current protection current loop or the over-voltage protection loop contribute to an over-current protection signal.

An amplifier unit includes an amplifier, a bias circuit, an inductor, a variable resistor circuit, and a control circuit. The amplifier includes an amplifier transistor that amplifies an input radio-frequency signal. The bias circuit is connected to the amplifier. The inductor is connected between and in series with the amplifier and the bias circuit. The variable resistor circuit is connected to the inductor. The control circuit includes a measuring circuit and a comparison circuit. The measuring circuit measures an amplification characteristic value of the amplifier transistor. The comparison circuit compares the amplification characteristic value measured by the measuring circuit with a reference value. The control circuit controls the variable resistor circuit based on a comparison result of the comparison circuit.

In an example, a system includes an amplifier configured to produce a bandgap voltage reference. The system also includes a current source configured to provide a current to bias the amplifier. The system includes a switching circuit configured to receive a first current replica signal and a second current replica signal, the switching circuit further configured to cause the current source to provide the current to bias the amplifier based on either the first current replica signal or the second current replica signal.

Circuits and methods for maintaining loop stability and good load regulation in low loop gain LDO regulator circuits. Embodiments encompass LDO regulator circuits that include an offset error correction circuit that generates an opposing voltage V.sub.OFFSET as a function of load current to substantially cancel out variations in V.sub.OUT that would otherwise occur due to load regulation limitations of the LDO regulator circuits. Embodiments use V.sub.OFFSET to imbalance currents in differential paths in a last-stage LDO error-amplifier so that an offset is propagated to a pair of inputs to the error-amplifier, thereby altering the output voltage V.sub.OUT to a corrected value. Benefits include improved LDO load regulation even when feedback loop gain is low, the available of both digital and analog implementations, high LDO accuracy and less variation of the output voltage V.sub.OUT, and suitability for implementation in integrated circuits for applications such as high precision power supplies.

Temperature compensation circuits and methods for adjusting one or more circuit parameters of a power amplifier (PA) to maintain approximately constant Gain versus time during pulsed operation sufficient to substantially offset self-heating of the PA. Some embodiments compensate for PA Gain “droop” due to self-heating using a Sample and Hold (S&H) circuit. The S&H circuit samples and holds an initial temperature of the PA at commencement of a pulse. Thereafter, the S&H circuit generates a continuous measurement that corresponds to the temperature of the PA during the remainder of the pulse. A Gain Control signal is generated that is a function of the difference between the initial temperature and the operating temperature of the PA as the PA self-heats for the duration of the pulse. The Gain Control signal is applied to one or more adjustable or tunable circuits within a PA to offset the Gain droop of the PA.

A device for buffering a reference signal comprises a regulator circuit configured to generate at least two replicas of the reference signal as regulated output signals. The device further comprises a receiving circuit configured to receive the regulated output signals in a switchable manner. In this context, the regulated output signals are configured to have different performance characteristics.

In an example, a system includes an amplifier configured to produce a bandgap voltage reference. The system also includes a current source configured to provide a current to bias the amplifier. The system includes a switching circuit configured to receive a first current replica signal and a second current replica signal, the switching circuit further configured to cause the current source to provide the current to bias the amplifier based on either the first current replica signal or the second current replica signal.

An apparatus for generating a steady state positive voltage (PVS) signal and a steady state negative voltage (NVS) signal is presented. The apparatus includes a bias signal generation module for generating a steady state reference voltage signal (RVS) based on a varying supply voltage signal (VDD), the RVS having a voltage level less than the PVS. The apparatus further includes a positive signal generation module (PSGM) generating the PVS, the PSGM including a first capacitor, the PSGM employing the first capacitor to generate a portion of the PVS based on the RVS. The apparatus further includes a negative signal generation module (NSGM) generating the NVS, the NSGM including a second capacitor, the NSGM employing the second capacitor to generate a portion of the NVS based on the RVS.

Described embodiments include an integrated circuit for temperature gradient compensation of a bandgap voltage. A bandgap core circuit has a bandgap feedback input, a bandgap adjustment input and a bandgap reference output. A resistor is coupled between the bandgap adjustment input and a ground terminal. An offset and slope correction circuit has an offset correction output that is coupled to the bandgap adjustment input. A signal at the offset correction output is trimmed at an ambient temperature. A thermal error cancellation (TEC) circuit has a TEC output coupled to the bandgap adjustment input. The TEC circuit includes first and second temperature sensors that are located apart from each other. A signal at the TEC output is responsive to temperatures at the first and second temperature sensors. An amplifier has an amplifier input and an amplifier output. The amplifier input is coupled to the bandgap reference output.

A radio-frequency module includes a multilayer substrate, a first semiconductor device, a second semiconductor device, and an anisotropic conductive resin component. The multilayer substrate includes a plurality of stacked layers, and has a first major face and a second major face. The first major face includes a first recess. The first semiconductor device is mounted over a bottom face of the first recess with the anisotropic conductive resin component interposed therebetween. The second semiconductor device is mounted over the first major face so as to overlie the first recess. The first semiconductor device is connected with a metallic via that extends through a portion of the multilayer substrate from the bottom face of the first recess to the second major face.