Transmit power control for multiple rate wireless communications

A radio frequency (RF) communication device that includes a power control loop for controlling output power for each of a plurality of different data rates, the RF communication device comprising:

• an output portion that includes a power detector and a variable output power amplifier having a gain input;
• a Baseband processor that receives a power level signal from the power detector and provides a corresponding power level value and that receives a power control value and asserts a power control signal to the gain input of the variable output power amplifier;
• and
• a control device that receives and compares an adjusted power level value with a predetermined set point value and generates a corresponding error value and that adjusts the power control value based on the error value, the control device using a data rate signal indicative of a selected data rate, the control device including:
• an input normalization adjust circuit that includes a first memory that stores one or more input adjustment values selected by the data select signal for adjusting the power level value;
• and
• an output normalization adjust circuit that includes a second memory that stores one or more output adjustment values selected by the data select signal for adjusting the power control value.

A method of calibrating a radio frequency (RF) transmitter to maximize output power for each of a plurality of different data rates, the RF transmitter including a single power control loop that converges using a target power set point in a first memory during normal operation for each data rate, the RF transmitter further including a second memory for storing a plurality of output scale factors used to adjust a power control value and a third memory for storing a plurality of input scale factors used to adjust a power level value, the input and output scale factors selected by a data rate signal indicative of operating data rate, said method comprising:

• opening the control loop during calibration;
• operating the RF transmitter with the opened control loop using a selected first data rate while measuring output power metrics including a spectral leakage metric and a distortion metric;
• applying and adjusting a power control value at an input of the opened control loop until a maximum desired power level is achieved for the data rate when either one of the spectral leakage metric and the distortion metric is maximized, resulting in a first power control value;
• storing a power level value at an output of the opened control loop into the first memory as the target power set point;
• and
• operating the RF transmitter with the opened control loop for each of one or more additional data rates while measuring the spectral leakage and distortion metrics, and for each additional data rate:
• determining a new power control value and a new power level value when a new maximum desired power level is achieved for a corresponding data rate when either one of the spectral leakage metric and the distortion metric is maximized;
• storing an output scale factor for the corresponding data rate in the second memory, the output scale factor representing a differential between the first power control value and the new power control value;
• and
• storing an input scale factor for the corresponding data rate in the third memory, the input scale factor representing a differential between the target power set point and the new power level value.