Electronic device and method of controlling transmission power

1. An electronic device comprising:

a temperature sensor;

a power amplifier (PA); and

a processor configured to:

determine a transmission power of the PA,

determine whether the determined transmission power is less than or equal to a preset threshold level, the preset threshold level being set to distinguish between a high power mode and a low power mode,

monitor, when the determined transmission power is less than or equal to the preset threshold level, signals from the temperature sensor,

determine a bias value for the PA, based on the monitored signals, and

control the PA to amplify a signal for transmission based on the determined bias value,

wherein the processor is further configured to select the bias value using a temperature-based compensation table including bias values that vary according to a plurality of temperatures, and

wherein the bias value is set to maintain a first amplification gain at a first temperature higher than a specified temperature and is set to maintain a second amplification gain higher than the first amplification gain at a second temperature lower than the specified temperature.

2. The electronic device of claim 1 , further comprising a transceiver.

3. The electronic device of claim 2 , wherein the processor is further configured to:

receive, from an external device via the transceiver, information regarding a transmission level; and

determine the transmission power based on the received information.

4. The electronic device of claim 2 , wherein the processor is further configured to:

measure a feedback power output from a coupler configured to couple a signal output from the PA; and

determine the transmission power based on the measured feedback power.

5. The electronic device of claim 4 , wherein the processor is further configured to:

compare a transmission output power that is set corresponding to the transmission level with the measured feedback power,

vary the determined bias value, when an error range of a result of the comparing is greater than or equal to a threshold value, and

maintain the determined bias value when the error range is less than a threshold value.

6. The electronic device of claim 1 , wherein the processor comprises at least one of an application processor and a communication processor.

7. The electronic device of claim 1 , wherein the processor is further configured to:

measure an offset condition,

adjust the determined bias value, based on the measured offset condition, and

drive the PA with the adjusted bias value.

8. The electronic device of claim 7 , wherein the offset condition comprises at least one of a battery status, a received signal status, a direct current (DC)-DC voltage, a transmission feedback power, and a PA load.

9. The electronic device of claim 1 , further comprising an antenna configured to transmit the amplified signal.

10. A method of controlling transmission power, the method comprising:

determining a transmission power of a power amplifier (PA);

determining whether the determined transmission power is less than or equal to a preset threshold level, the preset threshold level being set to distinguish between a high power mode and a low power mode;

monitoring, when the determined transmission power is less than or equal to the preset threshold level, a temperature surrounding the PA;

determining a bias value for the PA based on the monitored temperature; and

controlling the PA to amplify a signal for transmission based on the determined bias value,

wherein determining the bias value comprises selecting the bias value using a temperature-based compensation table including bias values that vary according to a plurality of temperatures, and

wherein the bias value is set to maintain a first amplification gain at a first temperature higher than a specified temperature and is set to maintain a second amplification gain higher than the first amplification gain at a second temperature lower than the specified temperature.

11. The method of claim 10 , wherein determining the transmission power comprises:

receiving, from an external device, via a transceiver, information regarding a transmission level; and

determining the transmission power based on the received information.

12. The method of claim 11 , wherein determining the transmission power further comprises:

measuring a feedback power output from a coupler configured to couple a signal output from the PA; and

determining the transmission power based on the measured feedback power.

13. The method of claim 12 , further comprising:

comparing a transmission output power that is set corresponding to the transmission level with the measured feedback power;

varying the determined bias value, when an error range of a result of the comparing is greater than or equal to a threshold value; and

maintaining the determined bias value when the error range is less than the threshold value.

14. The method of claim 10 , further comprising:

measuring an offset condition,

adjusting the determined bias value based on the measured offset condition, and

driving the PA with the adjusted bias value.

15. The method of claim 14 , wherein the offset condition comprises at least one of a battery status, a received signal status, a direct current (DC)-DC voltage, a transmission feedback power, and a PA load.