Abstract: Voltage regulation schemes for powering multiple circuit blocks are disclosed. In certain embodiments, a front end system includes a reference voltage circuit that receives power from a power supply voltage and generates a reference voltage, a group of circuit blocks each selectively enabled by a corresponding one of a group of enable signals, and a programmable voltage regulator that generates a programmable regulated voltage based on the reference voltage and provides the programmable regulated voltage to the circuit blocks. The programmable regulated voltage has a voltage level that changes based on a selection of the circuit blocks that are enabled by the enable signals.

Abstract: According to at least one aspect, a controller having a mode of operation including one of an on mode and an off mode is provided including a voltage supply node, a mode of operation signal node, a powered component, a switching device coupled in series between the voltage supply node and the powered component, a power supply detector coupled to the switching circuit, the voltage supply node, and the mode of operation signal node, the power supply detector being configured to receive a mode of operation signal indicative of the mode of operation of the controller from the mode of operation signal node, determine that the controller is in the off mode based on the mode of operation signal, and control the switching device to prevent a current from passing from the voltage supply node to the powered component responsive to determining that the controller is in the off mode.

Abstract: Cascode power amplifier bias circuits suitable for operating across multiple power supply domains are provided. In certain embodiments, a power amplifier system includes a cascode power amplifier and a multi-domain bias circuit that generates at least a first cascode bias voltage for the cascode power amplifier. The multi-domain bias circuit includes a coarse regulator that generates a regulated voltage based on a power supply voltage that is operable with multiple voltage levels associated with different power supply domains, a bandgap reference circuit that is powered by the regulated voltage and outputs a bandgap reference voltage, a bias voltage generator that generates multiple selectable bias voltages based on the bandgap reference voltage, and a bias voltage selector that chooses the first cascode bias voltage from amongst the selectable bias voltages.

Abstract: Apparatus and methods for bandgap reference generators are disclosed. In certain embodiments, a bandgap reference generator includes a low voltage bandgap reference circuit that generates a first bandgap reference voltage, a high voltage bandgap reference circuit that generates a second bandgap reference voltage, a bandgap selector circuit that outputs the first bandgap reference voltage or the second bandgap reference voltage as a selected bandgap reference voltage based on a voltage level of the power supply voltage, and a bandgap translator circuit that generates a buffered bandgap reference voltage based on the selected bandgap reference voltage.

Abstract: Methods related to controlling switches. In some embodiments, a method for controlling a radio-frequency switch can include providing or generating a control signal to allow generation of a plurality of reference levels by a regulator, or to allow the regulator to be in sleep mode. The method can further include operating the regulator based on the control signal to generate the plurality of reference voltage levels for operation of the radio-frequency switch, or to be in the sleep mode.

Abstract: Circuits, systems, and methods to switch modes based on temperature and to provide reference voltages are discussed herein. For example, a bandgap reference circuit may include one or more impedance elements and one or more switches coupled to the one or more impedance elements. The one or more switches may be controllable based on a temperature signal. The bandgap reference circuit may be configured to provide a bandgap reference voltage that is associated with less than a particular amount of voltage variation.

Abstract: Cascode power amplifier bias circuits suitable for operating across multiple power supply domains are provided. In certain embodiments, a power amplifier system includes a cascode power amplifier and a multi-domain bias circuit that generates at least a first cascode bias voltage for the cascode power amplifier. The multi-domain bias circuit includes a coarse regulator that generates a regulated voltage based on a power supply voltage that is operable with multiple voltage levels associated with different power supply domains, a bandgap reference circuit that is powered by the regulated voltage and outputs a bandgap reference voltage, a bias voltage generator that generates multiple selectable bias voltages based on the bandgap reference voltage, and a bias voltage selector that chooses the first cascode bias voltage from amongst the selectable bias voltages.

Abstract: A circuit assembly for generating a constant current, the circuit comprising: a resistor pair including a first resistor and a second resistor, the first resistor having a positive temperature coefficient and the second resistor having a negative temperature coefficient, the first and second resistors being configured such that the variability of resistance over temperature of the first resistor and the variability of resistance over temperature of the second resistor cancel to produce a zero temperature coefficient for the resistor pair; and a voltage input connected to the resistor pair and configured to receive an input voltage, the voltage input and the resistor pair configured to generate a current with a zero temperature coefficient.

Abstract: A method for generating a constant current. The method can include receiving an input voltage at a voltage input connected to a resistor pair, the resistor pair including a first resistor and a second resistor, the first resistor having a positive temperature coefficient and the second resistor having a negative temperature coefficient. The first and second resistors can be configured such that the variability of resistance over temperature of the first resistor and the variability of resistance over temperature of the second resistor cancel to produce a zero temperature coefficient for the resistor pair. The method can further include applying the input voltage to the resistor pair to generate a current with a zero temperature coefficient.

Abstract: Cascode power amplifier bias circuits suitable for operating across multiple power supply domains are provided. In certain embodiments, a power amplifier system includes a cascode power amplifier and a multi-domain bias circuit that generates at least a first cascode bias voltage for the cascode power amplifier. The multi-domain bias circuit includes a coarse regulator that generates a regulated voltage based on a power supply voltage that is operable with multiple voltage levels associated with different power supply domains, a bandgap reference circuit that is powered by the regulated voltage and outputs a bandgap reference voltage, a bias voltage generator that generates multiple selectable bias voltages based on the bandgap reference voltage, and a bias voltage selector that chooses the first cascode bias voltage from amongst the selectable bias voltages.

Abstract: A front-end module comprises a bias network including a current mirror, a junction temperature sensor, an n-bit analog-to-digital converter, an n-bit current source bank configured to automatically set reference current levels for one or more operating temperature regions, and a power amplifier. The bias network, junction temperature sensor, n-bit analog-to-digital converter, n-bit current source bank, and power amplifier are integrated on a first semiconductor die.

Abstract: A low-dropout (LDO) voltage regulation circuit comprises a first supply voltage, a first transistor, an overshoot control module, and coupling circuitry configured to couple the first supply voltage, the transistor, and the overshoot control module at a first node.

Abstract: A front-end module comprises a low-dropout (LDO) voltage regulator, a reference current generator, and a power amplifier. The LDO voltage regulator, reference current generator, and power amplifier are integrated on a first semiconductor die.

Abstract: Radio frequency (RF) front ends with integrated channel matching calibration are provided herein. In one aspect, a front end system includes: a plurality of front end amplification chains including transmit and receive chains for at least two radio frequency bands, each of the front end amplification chains configured to either transmit or receive radio frequency signals via one of a plurality of antennas, and each of the front end amplification chains includes an amplifier configured to receive a bias current and amplify the corresponding radio frequency signal based on the bias current, a control circuit configured to generate each of the bias currents, and a multiplexor configured to receive the bias currents and provide the bias currents to the corresponding amplifiers.

Abstract: Bias schemes for cascode power amplifiers are disclosed. In certain embodiments, a power amplifier system includes a cascode power amplifier powered by a first supply voltage and that amplifies a radio frequency input signal, and a bias circuit including a voltage regulator that generates a regulated voltage and is powered by the first supply voltage. The bias circuit further includes a bias voltage generation circuit that receives the regulated voltage and generates at least one cascode bias voltage for the cascode power amplifier, a switch that gates a second supply voltage to generate a gated supply voltage, a bias current generation circuit that controls a bias current of the cascode power amplifier and is powered by the gated supply voltage, and a gating circuit that controls the switch based on the regulated voltage and the second supply voltage.

Abstract: Bias schemes for cascode power amplifiers are disclosed. In certain embodiments, a power amplifier system includes a cascode power amplifier biased by a first cascode bias voltage and that amplifies a radio frequency input signal. The power amplifier system further includes a bias voltage generation circuit including a first switch, a first cascode transmit mode bias circuit that provides the first cascode bias voltage to the cascode power amplifier through the first switch in a normal power transmit mode, a low power mode bias circuit that overrides the first cascode transmit mode bias circuit to set the first cascode bias voltage in a low power transmit mode, a second switch, and a sleep mode bias circuit that provides the first cascode bias voltage to the cascode power amplifier through the second switch in a sleep mode.

Abstract: Programmable voltage regulators for powering multiple circuit blocks are disclosed. In certain embodiments, a front end system includes a plurality of circuit blocks, and a programmable low dropout regulator that generates a programmable regulated voltage for the plurality of circuit blocks based on a first multi-bit control signal. The programmable low dropout regulator includes a controllable frequency compensation circuit controlled by a second multi-bit control signal and operable to control a phase margin of the programmable low dropout regulator, and an overshoot control circuit controlled by a third multi-bit control signal and operable to control an overshoot of the programmable regulated voltage.

Abstract: Voltage regulation schemes for powering multiple circuit blocks are disclosed. In certain embodiments, a front end system includes a reference voltage circuit that receives power from a power supply voltage and generates a reference voltage, a group of circuit blocks each selectively enabled by a corresponding one of a group of enable signals, and a programmable voltage regulator that generates a programmable regulated voltage based on the reference voltage and provides the programmable regulated voltage to the circuit blocks. The programmable regulated voltage has a voltage level that changes based on a selection of the circuit blocks that are enabled by the enable signals.

Abstract: Methods related to controlling switches. In some embodiments, a method for controlling a radio-frequency switch can include providing or generating a control signal to allow generation of a plurality of reference levels by a regulator, or to allow the regulator to be in sleep mode. The method can further include operating the regulator based on the control signal to generate the plurality of reference voltage levels for operation of the radio-frequency switch, or to be in the sleep mode.

Abstract: Circuits, systems, and methods to automatically switch modes to provide constant reference voltages are discussed herein. For example, a bandgap reference system may include a first bandgap reference circuit configured to provide a first bandgap reference voltage, a low dropout regulator coupled to the first bandgap reference circuit, a temperature circuit coupled to the low dropout regulator, and a second bandgap reference circuit coupled to the low dropout regulator and the temperature circuit. The second bandgap reference circuit may be configured to configure one or more impedance elements based at least in part on a temperature signal and provide a second bandgap reference voltage based on one or more currents that pass through the one or more impedance elements.