Protection module for RF-amplifier

1. A protection module for protecting a RF-amplifier against overvoltage due to load impedance mismatch when said RF-amplifier is connected to a load RF-element, said protection module having an input terminal able to connect to a node belonging to a RF-signal transmission link from the RF-amplifier to the load RF-element, and the protection module also having a reference terminal able to connect to a reference terminal of the RF-amplifier, said protection module comprising:

a branch connecting the input terminal of the protection module to an intermediate node, said branch comprising at least one diode-like operating component;

a first resistance and a first capacitor connected in parallel to one another between the intermediate node and the reference terminal of the protection module; and

an inductor with a first terminal of said inductor connected to the input terminal of the protection module, wherein:

the branch further comprises a second resistance connected in series with respect to the at least one diode-like operating component between the input terminal and the intermediate node of the protection module; and

a second terminal of the inductor is connected to the intermediate node.

2. A protection module according to claim 1 , of integrated MOS-circuit type.

3. A protection module according to claim 1 , wherein the branch comprises several diode-like operating components connected in series between the input terminal of the protection module and the intermediate node, all the diode-like operating components being oriented with a common current flowing direction.

4. A protection module according to claim 3 , wherein a number of active ones among the diode-like operating components is variable, and the protection module further comprises a first controller arranged for controlling the number of active diode-like operating components.

5. A protection module according to claim 1 , wherein each diode-like operating component is a diode or a transistor connected so as to operate as a diode.

6. A protection module according to claim 1 , wherein the second resistance is of a variable resistance type, and the protection module further comprises a second controller arranged for controlling a value of the second resistance.

7. A protection module according to claim 1 , further comprising a VSWR sensing module arranged for sensing a value of a current through the second resistance.

8. A protection module according to claim 6 , wherein the VSWR sensing module is further arranged for providing the second controller with a control signal, so that said second controller controls the value of the second resistance based on the current sensed through the second resistance.

9. An electronic device comprising:

a source module adapted for producing a RF-signal;

a RF-amplifier connected to the source module for amplifying the RF-signal;

a load RF-element;

a RF-signal transmission link connecting an input terminal of the load RF-element to an output terminal of the RF-amplifier; and

a protection module according to claim 1 , with the input terminal and the reference terminal of said protection module connected respectively to a node belonging to the transmission link and to a reference terminal of the RF-amplifier.

10. An electronic device according to claim 9 , wherein the second resistance of the protection module is between 0.1 and 2 times an output resistance value of the RF-amplifier, said output resistance value being effective for a RF-voltage magnitude at the output of the RF-amplifier higher than 1.2 times a supply voltage value of said RF-amplifier.

11. An electronic device according to claim 9 , wherein the protection module and the RF-amplifier have one common integrated MOS circuit substrate.

12. An electronic device according to claim 9 , further comprising a supply sensing module for sensing a supply voltage value of the RF-amplifier,

and wherein the supply sensing module is connected to the first or second controller so as to control the number of active diode-like operating components or the value of the second resistance, respectively, as a function of the supply voltage value of the RF-amplifier.

13. An electronic device according to claim 8 , further comprising a monitoring module connected at input to the intermediate node.

14. An electronic device according to claim 8 , wherein the load RF-element comprises an antenna.

15. An electronic device according to claim 8 , adapted for forming part of a RF-transmission chain of a mobile communication equipment.

16. An electronic device according to claim 15 , wherein the mobile communication equipment is a mobile user terminal.