In an example, an integrated circuit includes a junction-gate field effect transistor (JFET), a current generator, a dynamic filter, and an output transistor. The JFET has a JFET gate, a JFET source, and a JFET drain, the JFET drain adapted to be coupled to a power supply. The current generator has a current generator input and current generator outputs, the current generator input coupled to the JFET source and a first of the current generator outputs coupled to the JFET gate. The dynamic filter has a dynamic filter input and a dynamic filter output, the dynamic filter input coupled to a second of the current generator outputs. The output transistor has an output transistor gate coupled to the dynamic filter output.

A bandgap reference voltage generating circuit includes a first current generator generating a first complementary-to-absolute temperature (CTAT) current and a first proportional-to-absolute temperature (PTAT) current, a second current generator generating a second CTAT current and a second PTAT current, and an output circuit outputting a reference voltage based on a difference between a first voltage based on the first CTAT current and the first PTAT current and a second voltage based on the second CTAT current and the second PTAT current, wherein the first CTAT current is cancelled by the second CTAT current.

Embodiments of a method and a device are disclosed. In an embodiment, a method for operating a bias controller for an amplifier circuit involves obtaining temperature data corresponding to a temperature of the amplifier circuit, generating a proportional to absolute temperature (PTAT) bias voltage based on a first PTAT slope when the temperature is within a first range of temperatures or a second PTAT slope when the temperature is within a second range of temperatures, wherein the second PTAT slope is greater than the first PTAT slope, and biasing the amplifier circuit based on the generated PTAT bias voltage.

Subsystems and methods disclosed herein provide a reference signal to a power amplifier (PA) of an RF transmitter or transceiver. PTAT and CTAT signals and a temperature indication signal are produced. Based on the temperature indication signal, one of the PTAT or CTAT signals is selected to be used to produce one or more DAC reference signals. Using the selected one of the PTAT or CTAT signals, the one or more DAC reference signals are produced and used to bias the DAC. A multi-bit digital input signal is converted to an analog output signal using the DAC that is biased using the one or more DAC reference signals (produced using the selected one of the PTAT or CTAT signals). Further, the analog signal output by the DAC, or an amplified version thereof, is used as the reference signal that is provided to the PA of the RF transmitter or transceiver.

Embodiments of the disclosure are drawn to a low-voltage temperature sensor. The temperature sensor may include a waveform generator, a complementary-to-absolute-temperature (CTAT) voltage generator, a voltage reference, two comparators, and digital logic. A waveform of the waveform generator may be compared to both the CTAT voltage and the voltage reference. The output of the comparison of the CTAT and the waveform may be a pulse-width modulated signal that is temperature-dependent. The output of the comparison of the voltage reference and the waveform may be a signal with constant pulse width. The digital logic may receive the pulsed signals and take a ratio of the two signals to determine a temperature.

The present invention provides a reference voltage buffer comprises a reference voltage generator, a first operational amplifier, a first transistor, a first group of resistors, a first load, a second transistor, a second group of resistors and a second load. In the reference voltage buffer, the first load and the second load use active device to increase the settling time, and the first load, the second load and the reference voltage generator of the reference voltage buffer are resigned to have the same characteristics in response to the temperature variation to overcome the PVT issue, and the first load and the second load of the reference voltage buffer use the open-loop design to have large full-scale of the output reference voltages.

A differential amplifier circuit includes: a control current source supplying a control current; paired bipolar transistors; an a variable resistance circuit including: a series circuit of a first resistor and a second resistor having an identical resistance, the series circuit electrically connected between a first terminal and a second terminal of the variable resistance circuit; a first field effect transistor (FET) having a source and a drain being electrically connected to emitters of the paired bipolar transistors, respectively; and a second FET having a drain, a gate being electrically connected to the drain thereof, the gate of the first FET, and a control terminal of variable resistance circuit, a source being electrically connected to a connection node between the first resistor and the second resistor, wherein the control current source adjusts the control current to allow transconductance of the second FET to be kept constant.

In an embodiment an electric circuit arrangement includes a current generator circuit having a first output terminal and to generate an output current, a controller configured to generate control signals to control the current generator circuit, a random code generator configured to generate random codes and a counter configured to generate a count, wherein the current generator circuit comprises a plurality of output current paths and a plurality of controllable switching circuits, wherein each of the output current paths includes a respective electrical component to define a current in the respective output current path, wherein a respective one of the controllable switching circuits is coupled to a respective one of the output current paths to connect the respective electrical component to the first output terminal, wherein the random code generator is configured to provide a respective code derived from a respective one of the random codes, and wherein the controller is configured to use the respective derived code or the count depending on the derived code to generate a respective one of the control signals to control a respective one of the controllable switching circuits of the current generator circuit.

A reference voltage generator circuit includes a band gap reference voltage circuit that generates a predetermined reference voltage, and a first correction current generator circuit that generates a first correction current in response to change in temperature. The first correction current generator circuit generates a plurality of voltage peaks in response to the change in temperature in the output voltage of the reference voltage generator circuit by injecting the first correction current into the band gap reference voltage circuit, and output voltage characteristics configuring each of the plurality of voltage peaks are made such that the output voltage varies continuously with respect to the change in temperature. The first correction current generator circuit includes a temperature setting circuit that can change the plurality of temperatures corresponding to each of the plurality of voltage peaks.

A bandgap reference circuit includes a plurality of current sources including different temperature coefficients, a first trimmer, and a mixer. The first trimmer adjusts current amounts for a plurality of currents, which are individually output from each of the plurality of current sources, to be equal to each other. The mixer adjusts an aggregate ratio and combines the plurality of currents based on the aggregate ratio.