Abstract: The invention provides a radio frequency (RF) module and associated method with envelope tracking (ET) power supply in a device. The RF module may comprise a plurality of transmitters, an ET output, and an ET multiplexer. Each said transmitter may comprise an ET port and one or more RF outputs, and may be configured for providing an RF signal to one of said one or more RF outputs, and providing an ET signal, which reflects an envelope of the RF signal, to the ET port. The ET multiplexer may be coupled between said ET ports of the plurality of transmitters and the ET output, for selectively relaying one of said ET ports to the ET output.

Abstract: The invention provides a radio frequency (RF) module and associated method with envelope tracking (ET) power supply in a device. The RF module may comprise a plurality of transmitters, an ET output, and an ET multiplexer. Each said transmitter may comprise an ET port and one or more RF outputs, and may be configured for providing an RF signal to one of said one or more RF outputs, and providing an ET signal, which reflects an envelope of the RF signal, to the ET port. The ET multiplexer may be coupled between said ET ports of the plurality of transmitters and the ET output, for selectively relaying one of said ET ports to the ET output.

Abstract: A low-noise voltage regulator circuit with quick disablement includes an amplifier for outputting a driving voltage according to a reference voltage, a feedback voltage on a feedback node, and an enable signal; an output transistor coupled among the amplifier, an output node, and a first voltage source for outputting an output voltage at the output node; a first discharge transistor having a first size and coupled among the enable signal, the output node, and the feedback node; and a second discharge transistor having a second size being different than the first size and coupled among the enable signal, the feedback node, and a second voltage source; wherein when the enable signal disables the amplifier, the enable signal turns on the first discharge transistor and the second discharge transistor such that the output voltage is quickly pulled down to close a level provided by the second voltage source.

Abstract: A temperature sensing apparatus for generating a sensing signal for indicating whether the temperature is higher or lower than a first threshold includes a bipolar junction transistor and a resistor. The bipolar junction transistor has a base terminal receiving a first constant voltage, an emitter terminal receiving a second constant voltage, and a collector terminal connecting to a node. The resistor is coupled between the node and a supply voltage. The first threshold is a value corresponding to the difference between the first and second constant voltages. The signal at the node is outputted to generate the sensing signal, which indicates the temperature is higher than the first threshold if the sensing signal is lower than a second threshold, and indicates the temperature is lower than the first threshold if the sensing signal is higher than the second threshold.

Abstract: A DC offset calibration device for calibrating a DC offset of an output signal of a gain stage, the DC offset calibration device includes: a digital-to-analog converter (DAC) electrically connected to the gain stage for generating an offset current according to the DC offset of the output signal of the gain stage; and a current-to-current converter electrically connected to the DAC and the gain stage for reducing the signal scale of the offset current to generate a compensation signal so as to reduce the DC offset at the output of the gain stage.

Abstract: A low-noise voltage regulator circuit with quick disablement includes an amplifier for outputting a driving voltage according to a reference voltage, a feedback voltage on a feedback node, and an enable signal; an output transistor coupled among the amplifier, an output node, and a first voltage source for outputting an output voltage at the output node; a first discharge transistor having a first size and coupled among the enable signal, the output node, and the feedback node; and a second discharge transistor having a second size being different than the first size and coupled among the enable signal, the feedback node, and a second voltage source; wherein when the enable signal disables the amplifier, the enable signal turns on the first discharge transistor and the second discharge transistor such that the output voltage is quickly pulled down to close a level provided by the second voltage source.

Abstract: A low-noise voltage regulator circuit with quick disablement is disclosed. The voltage regulator circuit includes an amplifier for outputting a driving voltage according to a reference voltage, a feedback voltage on a feedback node, and an enable signal; an output transistor coupled among the amplifier, an output node, and a first voltage source for outputting an output voltage at the output node; a first discharge transistor coupled among the enable signal, the output node, and the feedback node; and a second discharge transistor coupled among the enable signal, the feedback node, and a second voltage source; wherein when the enable signal disables the amplifier, the enable signal turns on the first discharge transistor and the second discharge transistor such that the output voltage is quickly pulled down to close a level provided by the second voltage source.

Abstract: A switchable linear regulator. The switchable linear regulator comprises a constant voltage source, a differential amplifier, a pass transistor, a first resistor, a plurality of second resistors and a plurality of switches. The differential amplifier has a first input terminal coupled to the constant voltage source and a second input terminal connected to a first node. The pass transistor has a first terminal controlled by the differential amplifier, a second terminal coupled to a supply voltage, and a third terminal connected to a second node. The first resistor is connected between the first and second nodes. Each second resistor comprises one end connected to the first node. Each switch is coupled between the other end of a corresponding second resistor and the ground.

Abstract: A DC offset calibration device for calibrating a DC offset of an output signal of a gain stage, the DC offset calibration device includes: a digital-to-analog converter (DAC) electrically connected to the gain stage for generating an offset current according to the DC offset of the output signal of the gain stage; and a current-to-current converter electrically connected to the DAC and the gain stage for reducing the signal scale of the offset current to generate a compensation signal so as to reduce the DC offset at the output of the gain stage.

Abstract: A low noise voltage regulator circuit with fast stable output voltage is disclosed. The low noise voltage regulator circuit contains a reference voltage generator, for generating a reference voltage; a switching circuit, which is electrically coupled to the output of reference voltage generator and has two states; and a stabilizing circuit. When the switching circuit is at a first state, the reference voltage is coupled to the stabilizing circuit without being filtered; when the switching circuit is at a second state, the reference voltage is filtered by a low pass filter before being coupled to the stabilizing circuit. A switching control signal is used to switch the switching circuit between the two states. The filtered reference voltage is used to generate a low noise regulated output voltage.

Abstract: A low-noise voltage regulator circuit with quick disablement is disclosed. The voltage regulator circuit includes an amplifier for outputting a driving voltage according to a reference voltage, a feedback voltage on a feedback node, and an enable signal; an output transistor coupled among the amplifier, an output node, and a first voltage source for outputting an output voltage at the output node; a first discharge transistor coupled among the enable signal, the output node, and the feedback node; and a second discharge transistor coupled among the enable signal, the feedback node, and a second voltage source; wherein when the enable signal disables the amplifier, the enable signal turns on the first discharge transistor and the second discharge transistor such that the output voltage is quickly pulled down to close a level provided by the second voltage source.

Abstract: A switched capacitor circuit for use in a voltage controlled oscillator (VCO) capable of minimizing clock feedthrough effect and an undesired momentary frequency drift in the VCO output frequency when the switched capacitor circuit is shut off. By gradually switching the switched capacitor circuit from an on state to an off state the clock feedthrough effect can be minimized. Several differently sized switch elements are used to selectively switch the capacitor from an internal capacitive node to ground. When switching the switched capacitor circuit to an off state, the control signals are sequenced to shut the switch elements off in order based on decreasing switch size. The smallest switch element can have a low-pass filter added to its control terminal to further decrease the clock feedthrough effect.

Abstract: A switched capacitor circuit for use in a voltage controlled oscillator (VCO) capable of minimizing clock feedthrough effect and an undesired momentary frequency drift in the VCO output frequency when the switched capacitor circuit is shut off. By gradually switching the switched capacitor circuit from an on state to an off state the clock feedthrough effect can be minimized. Several differently sized switch elements are used to selectively switch the capacitor from an internal capacitive node to ground. When switching the switched capacitor circuit to an off state, the control signals are sequenced to shut the switch elements off in order based on decreasing switch size. The smallest switch element can have a low-pass filter added to its control terminal to further decrease the clock feedthrough effect.

Abstract: A low noise voltage regulator circuit with fast stable output voltage is disclosed. The low noise voltage regulator circuit contains a reference voltage generator, for generating a reference voltage; a switching circuit, which is electrically coupled to the output of reference voltage generator and has two states; and a stabilizing circuit. When the switching circuit is at a first state, the reference voltage is coupled to the stabilizing circuit without being filtered; when the switching circuit is at a second state, the reference voltage is filtered by a low pass filter before being coupled to the stabilizing circuit. A switching control signal is used to switch the switching circuit between the two states. The filtered reference voltage is used to generate a low noise regulated output voltage.