Temperature compensated power detector
View Patent ↗A temperature-compensated power detector for detecting variations in the power level of an RF signal. The temperature-compensated power detector includes a detector circuit and a temperature compensating circuit. The detector circuit detects the power level of an RF signal and provides an output voltage that corresponds to the power level of the RF signal. The temperature compensating circuit ensures that the output voltage of the temperature-compensated power detector is independent of changes in the temperature.
1. A temperature-compensated power detector, the temperature-compensated power detector comprising:
a. a detector circuit, the detector circuit comprising at least one first diode, the at least one first diode detecting a power variation in an input RF signal from an RF signal source, the detector circuit having a first temperature coefficient; and
b. a temperature compensating circuit, the temperature compensating circuit comprising:
i. at least one voltage regulator, the at least one voltage regulator providing a regulated voltage with a second temperature coefficient; and
ii. at least one resistive divider, the at least one resistive divider being coupled to the at least one voltage regulator, the at least one resistive divider dividing each of the regulated voltage and the second temperature coefficient in a pre-defined ratio to provide a biasing voltage with a third temperature coefficient to the at least one first diode, wherein the third temperature coefficient corresponding to the biasing voltage is equal to the first temperature coefficient;
wherein the biasing current passing through the at least one first diode will remain constant.
2. The temperature-compensated power detector of claim 1 , wherein the detector circuit further comprises a first capacitor, the first capacitor isolating the RF signal source from a DC voltage of the at least one first diode, wherein the RF signal source provides the input RF signal to the detector circuit.
3. The temperature-compensated power detector of claim 1 , wherein the detector circuit further comprises one or more capacitors and one or more resistors, the one or more capacitors and the one or more resistors determining the discharging rate of the detector circuit.
4. The detector circuit of claim 1 , wherein the at least one first diode is a diode connected Bipolar Junction Transistor (BJT).
5. The temperature compensating circuit of claim 1 further comprising a capacitor, the capacitor providing a path for AC components of the input RF signal to ground.
6. The temperature-compensated power detector of claim 1 , wherein the at least one voltage regulator comprises at least one diode and at least one transistor, the at least one diode and the at least one transistor determining the second temperature coefficient of the at least one voltage regulator.
7. The at least one voltage regulator of claim 6 , wherein the at least one diode is a diode connected Bipolar Junction Transistor (BJT).
8. The temperature-compensated power detector of claim 1 , wherein the temperature compensating circuit further comprises a switch module, the switch module minimizing leakage current through the detector circuit when the at least one voltage regulator is not enabled.
9. The temperature-compensated power detector of claim 8 , wherein the switch module comprises at least one transistor.
10. The temperature-compensated power detector of claim 9 , wherein the at least one transistor is a Bipolar Junction Transistor (BJT).
11. The temperature-compensated power detector of claim 9 , wherein the at least one transistor is a Field Effect Transistor (FET).
12. The temperature-compensated power detector of claim 9 , wherein the at least one transistor is a pseudomorphic High Electron Mobility Transistor (pHEMT).
13. The temperature-compensated power detector of claim 1 , wherein the at least one voltage regulator is enabled by means of a control voltage.