Granted Patent B2

US 7,893,684 · App. 12/848,937 · Granted Feb 22, 2011

Abstract

Claims (23)

1. A power detector comprising:

a detection power input circuit for receiving an RF signal, said detection power input circuit comprises;

a first resistor including a first terminal for receiving the RF signal and including a second terminal,

a first capacitor including a first terminal coupled to the second terminal of the first resistor and including a second terminal, and

a second resistor including a first terminal coupled to the second terminal of the first capacitor and including a second terminal;

a bias circuit including an output for generating a bias signal in response to a reference control voltage, said bias circuit comprising;

a third resistor including a first terminal coupled to a reference voltage terminal and including a second terminal coupled to the second terminal of the second resistor,

a first bipolar transistor including a collector coupled to the second terminal of the third resistor, a base coupled to said collector, and an emitter, and

a fourth resistor including a first terminal coupled to the emitter of the first bipolar transistor and including a second terminal coupled to a ground terminal;

a detection circuit, having a second bipolar transistor having a collector, emitter and base, for generating a power control voltage at the emitter, having a voltage characteristic that offsets temperature characteristics of the received RF signal, which can be adjusted independently by the size of the first and second bipolar transistors, with the detection circuit forming a current mirror with the bias circuit, wherein said detection circuit comprises;

said second bipolar transistor including a collector coupled to a voltage supply terminal, including a base coupled to the first terminal of the second resistor, and including an emitter,

a fifth resistor including a first terminal coupled to the emitter of the second bipolar transistor and including a second terminal coupled to the ground terminal,

a second capacitor including a first terminal coupled to the emitter of the second bipolar transistor and including a second terminal coupled to the ground terminal, and

a sixth resistor including a first terminal coupled to the emitter of the second bipolar transistor and including a second terminal for providing the detector voltage output;

wherein the detection circuit operates as a current mirror circuit to the bias circuit with temperature compensation which is independently adjustable by the fourth resistor and the fifth resistor.

2. The power detector of claim 1 wherein the detection circuit is further arranged as an emitter follower for enveloping the RF signal.

3. The power detector of claim 1 wherein the bias circuit provides DC compensation to a power amplifier coupled thereto.

4. The power detector of claim 1 wherein a power amplifier is coupled to the bias circuit, the power amplifier including a driver stage providing said RF signal.

5. The power detector of claim 1 wherein the detection power input circuit, the bias circuit, the detection circuit, and a power amplifier are formed on a single integrated circuit.

6. The power detector of claim 4 wherein the detection circuit compensates temperature variation of an inputted detection voltage.

7. The power detector of claim 6 wherein the inputted detection voltage is received from an interstage of a power amplifier.

8. The power detector of claim 4 wherein the power amplifier comprises a driver stage and a power stage.

9. The power detector of claim 1 , wherein the emitter of the first bipolar transistor is not directly electrically connected to the emitter of the second bipolar transistor.

Assignments (15)