Forward isolation in power amplifier modules using internal regulator
A power amplifier module includes a transistor and transistor control circuitry configured to receive an internal regulator voltage and provide the internal regulator voltage to control the transistor in a stand-by mode of operation.
1. A power amplifier module comprising:
a transistor; and
transistor control circuitry configured to receive an internal regulator voltage and provide the internal regulator voltage to control the transistor in a stand-by mode of operation.
2. The power amplifier module of claim 1 wherein the transistor control circuitry is further configured to receive a voltage regulator voltage and provide the voltage regulator voltage to control the transistor when the power amplifier module is in an active OFF mode of operation.
3. The power amplifier module of claim 2 wherein the transistor control circuitry is further configured to provide the voltage regulator voltage to control the transistor when the voltage regulator voltage is greater than the internal regulator voltage and to provide the internal regulator voltage to control the transistor when the voltage regulator voltage is less than the internal regulator voltage.
4. The power amplifier module of claim 2 wherein the transistor control circuitry is further configured to receive a charge pump voltage and provide the charge pump voltage to control the transistor when the power amplifier module is in the active ON mode of operation.
5. The power amplifier module of claim 2 wherein the transistor control circuitry comprises a control transistor configured to receive the voltage regulator voltage at a first terminal of the control transistor and receive the internal regulator voltage at a second node of the control transistor.
6. The power amplifier module of claim 5 wherein the control transistor is one transistor of a transistor stack coupled to the transistor.
7. The power amplifier module of claim 1 wherein said providing the internal regulator voltage to control the transistor causes the transistor to be in an ON state.
8. The power amplifier module of claim 1 wherein the internal regulator voltage is between 1.0 and 1.5 V.
9. A method of operating a power amplifier module comprising:
receiving a voltage regulator voltage at a first input node;
receiving an internal regulator voltage at a second input node;
receiving a charge pump voltage at a third input node; and
providing the internal regulator voltage from the second input node to control a transistor of a power amplifier module when the power amplifier module is in a stand-by mode of operation.
10. The method of claim 9 wherein the internal regulator voltage is generated from a bandgap reference.
11. The method of claim 9 wherein, when the power amplifier module is in the stand-by mode of operation, the power amplifier module is not fully powered.
12. The method of claim 9 wherein, when the power amplifier module is in the stand-by mode of operation, the internal regulator voltage is greater than the voltage regulator voltage.
13. The method of claim 9 further comprising providing the voltage regulator voltage from the first input node to control the transistor when the power amplifier module is in an active OFF mode of operation.
14. The method of claim 13 further comprising providing the charge pump voltage from the third input node to control the transistor when the power amplifier module is in an active ON mode.
15. The method of claim 14 wherein, when the power amplifier module is in the active ON mode or the active OFF mode, the voltage regulator voltage is greater than the internal regulator voltage.
16. The method of claim 15 wherein, when the power amplifier module is in the active ON mode or the active OFF mode, the power amplifier module is powered-up.
17. A circuit comprising:
a first input node connected to a voltage regulator voltage;
a second input node connected to an internal regulator voltage;
a third input node connected to a charge pump voltage; and
connection circuitry configured to connect the first input node to one or more transistors of a switching circuit when the switching circuit is in an active OFF mode, to connect the second input node to the one or more transistors of the switching circuit when the switching circuit is in a stand-by mode, and to connect the third input node to the one or more transistors of the switching circuit when the switching circuit is in an active ON mode.
18. The circuit of claim 17 wherein, when the switching circuit is in the stand-by mode, the switching circuit is not fully powered.
19. The circuit of claim 17 wherein, when the switching circuit is in the stand-by mode, the internal regulator voltage is greater than the voltage regulator voltage.
20. The circuit of claim 17 wherein, when the switching circuit is in the active ON mode or the active OFF mode, the voltage regulator voltage is greater than the internal regulator voltage.