The present disclosure provides a bandgap reference circuit which includes a basic reference module to generate a basic reference voltage containing a first linear temperature-coefficient (TC) voltage and a first nonlinear TC voltage when a terminal node in the basic reference module is grounded. The bandgap reference circuit further includes a compensation module with an output node coupled to the terminal node of the basic reference module. The compensation module generates a compensation voltage at the output node with a second linear TC term and a second nonlinear TC term by using a first set of current sources proportional to absolute temperate (PTAT) and a second set of current sources with TC of zero. And the bandgap reference circuit combines the basic reference voltage and the compensation voltage, cancelling all the linear and nonlinear terms, and thus create a composite reference voltage independent of temperature.

The present disclosure provides a bandgap reference circuit which includes a basic reference module to generate a basic reference voltage containing a first linear temperature-coefficient (TC) voltage and a first nonlinear TC voltage when a terminal node in the basic reference module is grounded. The bandgap reference circuit further includes a compensation module with an output node coupled to the terminal node of the basic reference module. The compensation module generates a compensation voltage at the output node with a second linear TC term and a second nonlinear TC term by using a first set of current sources proportional to absolute temperate (PTAT) and a second set of current sources with TC of zero. And the bandgap reference circuit combines the basic reference voltage and the compensation voltage, cancelling all the linear and nonlinear terms, and thus create a composite reference voltage independent of temperature.

The present disclosure provides a circuit for generating a complimentary to absolute temperature (CTAT) voltage reference. The primary contributor to the voltage reference is first bipolar junction transistor, which is configured in diode mode, to produce the CTAT voltage. Such references include a non-linear component. A pair of bipolar junction transistors are coupled to the first bipolar junction transistor, and are configured to generate a delta base-emitter voltage. By coupling one of the pair to a proportional to absolute temperature current source, and the other to a current course which is substantially independent of absolute temperature, a further non-linear component is introduced, which is complimentary to the non-linear component introduced by the first bipolar junction transistor. The pair of bipolar transistors share a common emitter area size. As such, the non-linear component of the first bipolar junction transistor is compensated by the delta base-emitter arrangement, resulting in a more linear output.

An apparatus for generating a temperature-dependent current. The apparatus includes an input current scaling circuit configured to generate a first current that varies with temperature in accordance with a first programmable slope, and a second current that varies with temperature in accordance with a second programmable slope; and a current temperature blending circuit configured to generate a third current based on the first current over a first temperature range and the second current over a second temperature range, wherein the first temperature range is different than the second temperature range.

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.

An apparatus is provided which includes: a first supply node; a second supply node; a first transistor coupled to the first supply node, the first transistor is to provide a first current which is complementary to absolute temperature (CTAT); a second transistor coupled to the first supply node, the second transistor is to provide a second current which is proportional to absolute temperature (PTAT); a resistive device coupled in series at a node with the first and second transistors, and coupled to the second supply node, wherein the node is to sum the CTAT and the PTAT currents.

Certain aspects of the present disclosure provide methods and apparatus for current-limiting protection of an amplifier, such as a power amplifier in a radio frequency (RF) front-end. One example current-limiting circuit generally includes a node coupled to a current source, a plurality of current-sinking devices coupled to the node, one or more switches coupled between the node and at least one of the plurality of current-sinking devices, and a bias circuit having an input coupled to the node and an output for coupling to an input of the amplifier.

Example implementations include a bandgap voltage device with a first current source operatively coupled to a bandgap input node and a bandgap output node and operable to output a first proportional-to-absolute-temperature (PTAT) current, a current mirror including a first bandgap transistor and a second bandgap transistor, and operatively coupled to the bandgap output node, and a second current source operatively coupled to the current mirror and operable to output a second PTAT current. Example implementations also include a bandgap transistor device with a first P+ layer proximate to a center of a planar surface of a transistor device, a first N+ layer at least partially surrounding the first P+ layer along the planar surface, a second P+ layer at least partially surrounding the first N+ layer along the planar surface, a second N+ layer at least partially surrounding the second P+ layer along the planar surface, and a third P+ layer at least partially surrounding the second N+ layer along the planar surface.

A curvature compensated bandgap circuit that is capable of matching best-in-class two (2) parts-per-million performance without over-temperature trimming. This improves performance metrics for precision voltage reference products without requiring individual device tuning during production thereof. A core bandgap circuit comprises a main operational amplifier having a second order bowed voltage response over temperature. A ptat circuit is coupled to the core bandgap circuit to provide a sigmoidal third order shape for the bandgap voltage.

A power amplifier configured to amplify a received input signal, and the power amplifier includes a bias circuit and an output stage circuit. The bias circuit includes a reference voltage circuit and a bias generating circuit. The reference voltage circuit receives the first system voltage and provides a reference voltage according to a first system voltage, and the reference voltage changes as the temperature of the wafer changes. The bias generating circuit receives the second system voltage and the reference voltage, and generates an operating voltage. The output stage circuit is coupled to the bias circuit to receive the operating voltage and the driving current to receive and amplify the input signal. When a chip temperature is changed, the bias generating circuit changes the operating voltage according to the reference voltage, such that the driving current approaches a predetermined value as the chip temperature rises.