Power control apparatus for mobile terminal

• US 20020193134A1
• Filed: 06/06/2002
• Published: 12/19/2002
• Est. Priority Date: 06/07/2001
• Status: Active Grant

• Current Assignee: LG Electronics, Inc. (LG Corporation)
• Original Assignee: LG Electronics, Inc. (LG Corporation)
• Inventors: Kim, Gi-Mun
• Granted Patent: US 7,197,325 B2
• Time in Patent Office: Days
• US Class Current: 455/522
• CPC Class Codes: H03G 3/3042 in modulators, frequency-changers, transmitters or power amplifiers transmission power control in bidirectional transmission systems H04W52/04

Abstract

A transmission power control apparatus of a mobile terminal includes an intermediate frequency automatic gain controller for receiving a transmission intermediate frequency signal and performing an intermediate frequency automatic gain adjustment. A power amplifier for amplifying the transmission intermediate frequency signal. A mobile station modem (MSM) for outputting a transmission gain control signal to the intermediate frequency automatic gain controller, and a reference voltage control unit for receiving the transmission gain control signal and outputting a reference voltage to the power amplifier are also provided. Since the change of the reference voltage is always under control in the power mode switching, the burst noise occurrence due to the sudden reference voltage change in the transmission power can be restrained, and increased battery use time can be achieved by using a low reference voltage in the low power mode.

Claims

1. A transmission power control apparatus for a mobile terminal comprising:

a mobile station modem (MSM) for controlling a power control of the mobile terminal;

an intermediate frequency (IF) gain controller for adjusting IF gain of a transmission IF signal generated from a IF processor based on an IF gain control signal from the MSM;

a power amplifier module (PAM) for amplifying the adjusted transmission IF signal; and

a reference voltage control unit for adjusting reference voltage based on a transmission gain control signal from the MSM,

wherein the reference voltage control unit comprises;

a reference voltage tuner for tuning a voltage from a transmission power source and providing a reference voltage to the PAM; and

an actuator for actuating the reference voltage tuner based on the reference voltage tuner output and the transmission gain control signal from the MSM.

2. The apparatus of claim 1, wherein the reference voltage tuner further comprises:

a transistor of which a base terminal is connected to an output terminal of the actuator; and

a first resistor traversing an emitter and collector terminals of the transistor.

3. The apparatus of claim 2, wherein the collector terminal of the transistor is connected to a non-inverting terminal (+) of the actuator.

4. The apparatus of claim 3, wherein the transmission gain control signal is inputted to an inverting terminal (−

) of the actuator.

5. The apparatus of claim 4, wherein a power mode of the reference voltage tuner is determined by a voltage inputted to the non-inverting terminal (+).

6. The apparatus of claim 5, wherein if the voltage inputted to the non-inverting terminal (+) is a low power mode voltage, a high voltage is applied to the base terminal of the transistor, if the voltage inputted to the non-inverting terminal (+) is equal to or greater than the low power mode voltage, a low voltage is applied to the base terminal of the transistor.

7. The apparatus of claim 6, wherein when the voltage of the transmission gain control signal inputted to the inverting terminal (−

) is increased to exceed the low power mode voltage, the voltage to the non-inverting terminal (+) gradually increases up to the high power mode voltage.

8. The apparatus of claim 7, wherein the low power mode voltage is 1.5V.

9. The apparatus of claim 8, wherein while the low power mode voltage is applied to the non-inverting terminal (+), a serial resistance connected to the transmission power source is determined by an internal resistance of the transistor and a resistance of the first resistor.

10. The apparatus of claim 9, wherein if the voltage inputted to the non-inverting terminal (+) is equal to or greater than the low power mode voltage, the serial resistance to the transmission power source becomes ‘

0’

.

11. The apparatus of claim 2, further comprising a system mode select switch for selectively supplying an output of the power amplifier to the actuator.

12. The apparatus of claim 11, wherein if a system mode select signal from the MSM is low, the system mode select switch is turned off, if the system mode select signal from the MSM is high, the system mode select switch is turned on.

13. The apparatus of claim 12, wherein if the system mode select switch is OFF, the mobile terminal enters an advanced mobile phone system (AMPS) mode and the reference voltage tuner constantly operates in a high power mode.

14. The apparatus of claim 13, wherein when the system mode select switch is ON, the mobile terminal enters a code division multiple access (CDMA) mode and the power mode of the reference voltage tuner is set according to the transmission gain control signal.

15. The apparatus of claim 14, wherein if the mobile terminal enters the CDMA mode, the collector terminal of the transistor is connected to the non-inverting terminal (+) of the actuator.

16. The apparatus of claim 15, wherein the transmission gain control signal is inputted to the inverting terminal (−

) of the actuator.

17. The apparatus of claim 16, wherein the power mode of the reference voltage tuner is determined by a voltage inputted to the non-inverting terminal (+).

18. The apparatus of claim 17, wherein if the voltage inputted to the non-inverting terminal (+) is a low power mode voltage, a high voltage is applied to the base terminal of the transistor, if the voltage inputted to the non-inverting terminal (+) is equal to or greater than the low power mode voltage, a low voltage is applied to the base terminal of the transistor.

19. The apparatus of claim 18, wherein if the voltage of the transmission gain control signal inputted to the inverting terminal (−

) increases to reach the low power mode voltage, the voltage inputted to the non-inverting terminal (+) gradually increases up to the high power mode voltage.

20. The apparatus of claim 19, wherein the low power mode voltage is 1.5V.

21. The apparatus of claim 20, wherein while the low power mode voltage is being applied to the non-inverting terminal (+), a serial resistance connected to the transmission power source is determined by the internal resistance of the transistor and a resistance of the first resistor.

22. The apparatus of claim 21, wherein if the voltage inputted to the non-inverting terminal (+) is equal to or greater than the low power mode voltage, the serial resistance to the transmission power source becomes ‘

0’

.

23. The apparatus of claim 22, wherein the transmission gain control signal is TX_AGC_ADJ.

24. The apparatus of claim 23, wherein the transmission power source is VCC_TX.

26. The method as claimed in claim 25, the reference voltage tuning further comprising:

connecting a transistor base terminal to an output terminal of the actuator; and

traversing an emitter and collector terminals of the transistor by a first resistor.

27. The method as claimed in claim 26, the reference voltage tuning further comprising:

connecting the collector terminal of the transistor to a non-inverting terminal (+) of the actuator; and

inputting the transmission gain control signal to an inverting terminal (−

) of the actuator.

29. The method as claimed in claim 26, further comprising selecting on a system mode select switch for supplying an output of the power amplifier to the actuator.

30. The method as claimed in claim 29, the system mode selecting further comprising:

switching the system mode select swith to ON, the mobile terminal enters a code division multiple access (CDMA) mode and the power mode of the reference voltage tuner is set according to the transmission gain control signal; and

switching the system mode select swith to OFF, the mobile terminal enters an advanced mobile phone system (AMPS) mode and the reference voltage tuner constantly operates in high power mode.

25. A method of controlling transmission power for a mobile terminal comprising:

controlling a power control of the mobile terminal by a mobile station moderm (MSM);

adjusting an intermediate frequency (IF) gain of a transmission IF signal generated from an IF processor based on an IF gain control signal from the MSM;

amplifying the adjusted transmission IF signal by a power amlifier module (PAM); and

determining a reference voltage based on a transmission gain control signal from the MSM, wherein the reference voltage determining further comprising;

tuning a reference voltage from a transmission power source and prividing a reference voltage to the PAM by a reference voltage tuner; and

actuating the reference voltage tuner based on the reference voltage tuner output and the transmission gain control signal from the MSM by an actuator.

28. The method as claimed in 27, further comprising determining a power mode of the reference voltage tuner by a voltage inputted to the non-inverting terminal (+).