A dual-mode envelope tracking (ET) power management circuit is provided. An ET amplifier(s) in the dual-mode ET power management circuit is capable of supporting normal-power user equipment (NPUE) mode and high-power user equipment (HPUE) mode. In the NPUE mode, the ET amplifier(s) amplifies a radio frequency (RF) signal(s) to an NPUE voltage based on a supply voltage for transmission in an NPUE output power. In the HPUE mode, the ET amplifier(s) amplifies the RF signal(s) to an HPUE voltage higher than the NPUE voltage based on a boosted supply voltage higher than the supply voltage for transmission in an HPUE output power higher than the NPUE output power. The ET amplifier(s) maintains a constant load line between the NPUE mode and the HPUE mode. By maintaining the constant load line, it is possible to maintain efficiency of the ET amplifier(s) in both the NPUE mode and the HPUE mode.

A power amplifier module includes an amplifier that amplifies an input signal and outputs an amplified signal, an emitter follower transistor that supplies a bias signal to the amplifier to control a bias point of the amplifier, and a current source that supplies a control current which changes in accordance with a change in control voltage to a collector of the emitter follower transistor. The current source limits the control current to not greater than an upper limit.

A microwave power amplifier arrangement for an electron paramagnetic resonance (EPR) system provides amplified microwave pulses having a microwave frequency in the X-band. The arrangement has a microwave input and a microwave output, and comprises at least one transistor amplifier device, and at least one switchable reflection device. A respective transistor amplifier device comprises a transistor amplifier device input directly or indirectly connected to the microwave input (2), at least one transistor, and a transistor amplifier device output directly or indirectly connected to the microwave output. A respective switchable reflection device comprises a PIN diode and a lambda/4 line connected directly or indirectly to the transistor amplifier device output of at least one transistor amplifier device and to a first port of the PIN diode, with lambda being the wavelength of the microwave radiation within the lambda/4 line. A second port of the PIN diode is connected to ground.

Provided is a power amplification module that includes: a first transistor, a first signal being inputted to a base thereof; a second transistor, the first signal being inputted to a base thereof and a collector thereof being connected to a collector of the first transistor; a first resistor, a first bias current being supplied to one end thereof and another end thereof being connected to the base of the first transistor; a second resistor, one end thereof being connected to the one end of the first resistor and another end thereof being connected to the base of the second transistor; and a third resistor, a second bias current being supplied to one end thereof and another end thereof being connected to the base of the second transistor.

A power amplifier module includes an amplifier that amplifies an input signal and outputs an amplified signal, an emitter follower transistor that supplies a bias signal to the amplifier to control a bias point of the amplifier, and a current source that supplies a control current which changes in accordance with a change in control voltage to a collector of the emitter follower transistor. The current source limits the control current to not greater than an upper limit.

A power supply to power amplifier (PA) distribution network may include a first power supply. The PA distribution network may further include at least one power amplifier. The power amplifier may be coupled to the first power supply. The power amplifier may include a driver stage and a power stage. The power amplifier may be coupled to the first power supply via a first switch.

A dual-mode envelope tracking (ET) power management circuit is provided. An ET amplifier(s) in the dual-mode ET power management circuit is capable of supporting normal-power user equipment (NPUE) mode and high-power user equipment (HPUE) mode. In the NPUE mode, the ET amplifier(s) amplifies a radio frequency (RF) signal(s) to an NPUE voltage based on a supply voltage for transmission in an NPUE output power. In the HPUE mode, the ET amplifier(s) amplifies the RF signal(s) to an HPUE voltage higher than the NPUE voltage based on a boosted supply voltage higher than the supply voltage for transmission in an HPUE output power higher than the NPUE output power. The ET amplifier(s) maintains a constant load line between the NPUE mode and the HPUE mode. By maintaining the constant load line, it is possible to maintain efficiency of the ET amplifier(s) in both the NPUE mode and the HPUE mode.

A power amplifier module includes an amplifier that amplifies an input signal and outputs an amplified signal, an emitter follower transistor that supplies a bias signal to the amplifier to control a bias point of the amplifier, and a current source that supplies a control current which changes in accordance with a change in control voltage to a collector of the emitter follower transistor. The current source limits the control current to not greater than an upper limit.

A power amplifier module includes an amplifier that amplifies an input signal and outputs an amplified signal, an emitter follower transistor that supplies a bias signal to the amplifier to control a bias point of the amplifier, and a current source that supplies a control current which changes in accordance with a change in control voltage to a collector of the emitter follower transistor. The current source limits the control current to not greater than an upper limit.

Dual-output power converter circuitry includes an input node, a first output node, a second output node, a number of capacitive elements, and a number of switching elements. The switching elements are coupled between the input node, the first output node, the second output node, and the capacitive elements. In operation, the switching elements charge and discharge the capacitive elements such that a power supply output voltage is provided asynchronously to the first output node and the second output node.