TRANSMITTING POWER LEVEL CONTROLLER AND RELATED METHOD

• US 20090325517A1
• Filed: 06/25/2008
• Published: 12/31/2009
• Est. Priority Date: 06/25/2008
• Status: Active Grant

• Current Assignee: MediaTek, Inc.
• Original Assignee: MediaTek, Inc.
• Inventors: Fan, Sheng-Po
• Granted Patent: US 8,019,295 B2
• Time in Patent Office: Days
• US Class Current: 455/127.2
• CPC Class Codes: H03G 3/3042 in modulators, frequency-changers, transmitters or power amplifiers transmission power control in bidirectional transmission systems H04W52/04
• CPC Class Codes: H04W 52/36 with a discrete range or set of values, e.g. step size, ramping or offsets
• CPC Class Codes: H04W 52/52 using AGC [Automatic Gain Control] circuits or amplifiers

Abstract

A transmitting power level controller of a communication system includes a radio-frequency unit for generating a communication signal and a power amplifier for amplifying the communication signal to generate a transmitting signal. The transmitting power level controller has a temperature sensor, a power detector, and an automatic level controller. The temperature sensor senses temperature of at least one of the RF unit and the PA to generate a detected temperature signal. The power detector detects a transmitting power of the transmitting signal to generate a detected power signal. The automatic level controller is coupled to the temperature sensor and the power detector. The power detector adjusts the transmitting power of the transmit signal according to the detected power signal when a maximal transmitting power is in a predetermined range, and adjusts the transmitting power according to the detected temperature signal otherwise.

Claims

1. A transmitting power level controller of a communication system, the communication system comprising a radio-frequency (RF) unit for generating a communication signal and a power amplifier (PA) for amplifying the communication signal to generate a transmitting signal, the transmitting power level controller comprising:

a temperature sensor, for sensing temperature of at least one of the RF unit and the PA to generate a detected temperature signal;

a power detector, for detecting a transmitting power of the transmit signal to generate a detected power signal; and

an automatic level controller, coupled to the temperature sensor and the power detector, for adjusting the transmitting power of the transmitting signal according to the detected power signal when a maximal transmitting power is in a predetermined range, and adjusting the transmitting power according to the detected temperature signal otherwise.

2. The transmitting power level controller of claim 1 wherein the automatic level controller comprises a power setting unit comprising:

a subtracting unit, for generating a difference according to the detected power signal and a target transmitting power; and

a weighting unit, coupled to the subtracting unit, for generating a weighted difference according to the difference;

wherein the automatic level controller adjusts the transmitting power according to the weighted difference.

3. The transmitting power level controller of claim 2 wherein the power setting unit further comprises:

an average unit, coupled to the weighting unit, for generating an average difference according to an output signal of the weighting unit;

wherein the automatic level controller adjusts the transmitting power according to the average difference.

4. The transmitting power level controller of claim 1 wherein the temperature sensor senses temperature of the PA to generate the detected temperature signal, and the automatic level controller comprises a power setting unit comprising:

a subtracting unit, for generating a difference according to the detected temperature signal and a reference PA temperature; and

a weighting unit, coupled to the subtracting unit, for generating a weighted difference according to the difference;

wherein the automatic level controller adjusts the transmitting power according to the weighted difference.

5. The transmitting power level controller of claim 1 wherein the temperature sensor senses temperature of the RF unit to generate the detected temperature signal, and the automatic level controller comprises a power setting unit comprising:

a subtracting unit, for generating a difference according to the detected temperature signal and a predetermined RF temperature; and

a weighting unit, coupled to the subtracting unit, for generating a weighted difference according to the difference;

wherein the automatic level controller adjusts the transmitting power according to the weighted difference.

6. The transmitting power level controller of claim 1 wherein the automatic level controller adjusts the transmitting power by adjusting a baseband gain of the communication system in fractional dB and adjusting a radio frequency gain of the communication system in integral dB.

7. The transmitting power level controller of claim 1 further comprising:

a comparator, for comparing the maximal transmitting power and a threshold to generate a comparison result;

a multiplexer (MUX), coupled to the comparator, the temperature sensor and the power detector, for selectively outputting the detected power signal or the detected temperature signal as an output signal according to the comparison result;

a programmable gain amplifier (PGA), coupled to the MUX, for amplifying the output signal to generate an amplified output signal;

an analog-to-digital converter (ADC), coupled to the PGA, for converting the amplified output signal to a digital output signal;

an accumulator, coupled to the ADC, for generating an accumulation signal by accumulating the digital output signal; and

a look-up table, coupled to the accumulator, for converting the accumulation signal to a measured temperature or a measured power;

wherein the automatic level controller adjusts the transmitting power according to the measured temperature or the measured power.

8. The transmitting power level controller of claim 7 wherein the look-up table converts the accumulation signal to the measured power according to the detected temperature signal.

9. The transmitting power level controller of claim 1 wherein the power detector further comprises a low pass filter for filtering out high frequency components of the detected power signal.

10. The transmitting power level controller of claim 1 wherein the power level control calculates the maximal transmitting power according to a symbol having maximal power in a frame of the communication signal, and the power level control calculates the maximal transmitting power frame by frame.

11. The transmitting power level controller of claim 1 wherein the transmitting automatic level controller generates the maximal transmitting power and the detected temperature signal at a first frame of the communication signal and adjusts the transmitting power at a second frame of the communication signal, the second frame being next to the first frame.

12. A method for adjusting transmitting power level of a communication system, wherein the communication system comprises a radio-frequency (RF) unit for generating a communication signal and a power amplifier (PA) for amplifying the communication signal to generate a transmitting signal, the method comprising:

sensing temperature of at least one of the RF unit and the PA to generate a detected temperature signal;

detecting a transmitting power of the transmitting signal to generate a detected power signal; and

adjusting the transmitting power of the transmitting signal according to the detected power signal when a maximal transmitting power is in a predetermined range, and adjusting the transmitting power according to the detected temperature signal otherwise.

13. The method of claim 12 further comprising:

generating a difference according to the detected power signal and the transmitting power; and

generating a weighted difference according to the difference; and

adjusting the transmitting power according to the weighted difference.

14. The method of claim 13 further comprising:

generating an average difference according to an output signal of the weighting unit; and

adjusting the transmitting power according to the average difference.

15. The method of claim 12 further comprising:

sensing temperature of the PA to generate the detected temperature signal;

generating a difference according to the detected temperature signal and a predetermined PA temperature;

generating a weighted difference according to the difference; and

adjusting the transmitting power according to the weighted difference.

16. The method of claim 12 wherein the temperature sensor senses temperature of the RF unit, and the automatic level controller comprises:

sensing temperature of the RF unit to generate the detected temperature signal;

generating a difference according to the detected temperature signal and a predetermined RF temperature;

generating a weighted difference according to the difference; and

adjusting the transmitting power according to the weighted difference.

17. The method of claim 12 further comprising:

adjusting the transmitting power by adjusting a baseband gain of the communication system in fractional dB and adjusting a radio frequency gain of the communication system in integral dB.

18. The method of claim 12 further comprising:

calculating the maximal transmitting power according to a symbol having maximal power in a frame of the communication signal frame; and

calculating the maximal transmitting power frame by frame.

19. The method of claim 12 further comprising:

generating the maximal transmitting power and the detected temperature signal at a first frame of the communication signal; and

adjusting the transmitting power at a second frame of the communication signal, the second frame being next to the first frame.