Automatic Gate Bias Control of RISC Processor ARM LPC148

An intelligent gate voltage control system is designed in accordance with changes of temperature and drain current through the platform of transplanting OS system to the main-controller ARM 7 (ARM7) to real-time compensate for the deterioration of the linear MOS PA at different points of temperature. With the interrelation of the temperature, bias gate voltage and drain current, real-time monitoring of drain current achieves high stability, high precision of the gate voltage output capability under the conditions of measured temperature. Meanwhile after the process of embedded ARM, system could output optimal gate voltage value quickly, accurately and stably at any temperature, which also can enhance the system performance of MOS power amplifier. The provision of stable gate voltage for power amplifier is of great importance in the design of RF power amplifiers. Since the gate voltage will affect the quiescent current of MOS. The quiescent current is very susceptible to influence of temperature leading to its Q point drift, which would influence the best matching load, efficiencies and other parameters of power amplifier.