# US 2014/0191806 A1 · Electronic system - radio frequency power amplifier and method for dynamic adjusting bias point > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2014/0191806 A1 - Document ID: US20140191806A1 - Status: Published application - Kind: A1 - Application number: 14/098,883 - Filed: 2013-12-06 - Published: 2014-07-10 - Earliest claimed: 2013-01-04 - Assignees: Advanced Semiconductor Engineering, Inc. - Applicants: Advanced Semiconductor Engineering Inc. - Inventors: JAW-MING DING; CHIEN-YEH LIU - Web page: https://patentgrep.com/patent/US20140191806A1 ## CPC - H03F 3/191: Tuned amplifiers (H03F3/193, H03F3/195 take precedence) - H03F 1/0266: {by using a signal derived from the input signal} - H03F: AMPLIFIERS ## Abstract A radio frequency (RF) power amplifier is disclosed. The RF power amplifier includes a bias circuit, an output stage circuit and dynamic bias controlling circuit. The bias circuit receives a first system voltage and provides a working voltage accordingly. The output stage circuit receives the working voltage so as to work at an operation bias point. The dynamic bias controlling circuit detects a RF input signal and outputs a compensation voltage to the bias circuit according to variation of the RF input signal, wherein the dynamic bias controlling circuit is an open loop configuration. When an input power of the RF input signal increases and makes the working voltage decreases so as to shift the operation bias point, the bias circuit adjusts the working voltage upward so as to recover or enhance the operation bias point according to the compensation voltage received. ## Claims ### Claim 1 A RF power amplifier, used for amplifying a RF input signal received, the RF power amplifier comprising: a bias circuit, receiving a first system voltage, and providing a work voltage according to the first system voltage; an output-stage circuit, electrically connected to the bias circuit, the output-stage circuit receiving the work voltage so as to operate at an operation bias point; and a dynamic bias controlling circuit, electrically connected between the bias circuit and the output-stage circuit, the dynamic bias controlling circuit detecting the RF input signal and outputting a compensation voltage to the bias circuit according to change of the RF input signal, wherein when input power of the RF input signal increases such that the operation bias point offsets and the work voltage decreases, the work voltage is increased by the bias circuit according to the compensation voltage received so as to recover or elevate the operation bias point. ### Claim 2 (depends on 1) The RF power amplifier according to claim 1, wherein the bias circuit comprises: a first transistor, having an emitter connected to a ground voltage, a base connected to the dynamic bias controlling circuit for receiving a compensation voltage; a second transistor, having a base connected to a collector of the first transistor, a collector connected to the first system voltage; a first reference resistor, having one terminal connected to the first system voltage, another terminal connected to the base of the second transistor, wherein the first reference resistor is used for generating a first reference current; a first resistor, having one terminal connected to an emitter of the second transistor, another terminal connected to the base of the first transistor; and a second resistor, having one terminal connected to the emitter of the second transistor, another terminal connected to the output-stage circuit and outputting the work voltage, wherein the first reference current is equal to sum of collector current of the first transistor and base current of the second transistor. ### Claim 3 (depends on 2) The RF power amplifier according to claim 2, wherein when input power of the RF input signal increases, the base of the first transistor receives the compensation voltage corresponding and accordingly the base current and the collector current of the first transistor decrease such that base current and emitter current of the second transistor increase, so as to increase the work voltage for recovering or elevating the operation bias point. ### Claim 4 (depends on 1) The RF power amplifier according to claim 1, wherein the output-stage circuit comprises: a third transistor, having a base receiving the work voltage, an emitter connected to the ground voltage, a collector connected to a second system voltage, wherein in an AC signal mode, the third transistor is used for amplifying the RF input signal received and outputs a RF output signal at the collector of the third transistor itself. ### Claim 5 (depends on 2) The RF power amplifier according to claim 2, wherein the dynamic bias controlling circuit comprises: a second reference resistor, having one terminal connected to the first system voltage, another terminal connected to a collector of the fourth transistor, wherein the collector of the fourth transistor is connected to another terminal of the second reference resistor, an emitter of the fourth transistor is connected to the ground voltage, a base of the fourth transistor receives the RF input signal and detecting change of the RF input signal, and the fourth transistor is served as a power detecting transistor; a third resistor, having one terminal connected to one terminal of the second resistor, another terminal connected to the base of the fourth transistor; a fifth resistor, having one terminal connected to another terminal of the third resistor, another terminal outputting the compensation voltage; a first capacitor, having one terminal connected to the another terminal of the fifth resistor, another terminal connected to the ground voltage, wherein resistance value of the first reference resistor is equal to resistance value of the second reference resistor, wherein the fifth resistor and the first capacitor is used for filtering high frequency signal in the AC signal mode. ### Claim 6 (depends on 5) The RF power amplifier according to claim 5, wherein the resistance value of the first resistor is equal to resistance value of the third resistor. ### Claim 7 (depends on 1) An electronic system, comprising: a RF power amplifier according to claim 1, the RF power amplifier receiving a RF input signal and outputting a RF output signal; and a load, connected to the RF power amplifier, the load receiving the RF output signal, wherein when input power of the RF input signal increases, the RF power amplifier stabilizes the operation bias point via a compensation circuit. ### Claim 8 (depends on 7) The electronic system according to claim 7, wherein the bias circuit comprises: a first transistor, having an emitter connected to a ground voltage, a base connected to the dynamic bias controlling circuit for receiving a compensation voltage; a second transistor, having a base connected to a collector of the first transistor, a collector connected to the first system voltage; a first reference resistor, having one terminal connected to the first system voltage, another terminal connected to the base of the second transistor, wherein the first reference resistor is used for generating a first reference current; a first resistor, having one terminal connected to an emitter of the second transistor, another terminal connected to the base of the first transistor, a second resistor, having one terminal connected to the emitter of the second transistor, another terminal connected to the output-stage circuit and outputting the work voltage, wherein the first reference current is equal to sum of collector current of the first transistor and base current of the second transistor. ### Claim 9 (depends on 1, 7) A method for dynamic adjusting bias point, comprising: receiving a system voltage and accordingly providing a work voltage via a bias circuit; receiving the work voltage and accordingly operating at an operation bias point via an output-stage circuit; and detecting input power of a RF input signal and outputting a compensation voltage for stabilizing the operation bias point according to change of input power via a dynamic bias controlling circuit; wherein the method for dynamic adjusting bias point is used for the RF power amplifier according to claim 1 or the electronic system according to claim 7. ### Claim 10 (depends on 9) The method for dynamic adjusting bias point according to claim 9, wherein when input power of the RF input signal increases such that the operation bias point offsets and the work voltage decreases, the work voltage is increased by the bias circuit according to the compensation voltage received so as to recover or elevate the operation bias point.