High and low power combination circuit of radio frequency power amplifier

Abstract

The invention discloses a high and low power combination circuit of a radio frequency power amplifier. The high and low power combination circuit is connected between an output signal and a load and comprises a high-power amplifier as a power level, a low-power amplifier and a control circuit, wherein the high-power amplifier and the low-power amplifier are connected in parallel, the control circuit is used for switching the two amplifiers to work and controlling the two amplifiers, the high-power amplifier and the low-power amplifier are connected with another amplifier as an output signal driving level, and the control circuit is used for controlling the continuous conduction of the driving-level amplifier and outputting bias current which is suitable for a high or low power working mode of the power level amplifier. In the high and low power combination circuit, the radio frequency power amplifier shares a driving level under the high and low power modes, simplifies inputting and matching network design and reduces the design difficulty of the circuit; and the high and low power combination circuit has the high and low power working modes, eliminates the efficiency influence ofthe low power mode by switch insertion loss through reasonably controlling the on-off of a radio frequency switch, effectively increases the average efficiency of the radio frequency power amplifierand prolongs the service life of batteries.

Description

technical field [0001] The invention relates to the technical field of radio frequency power amplifiers, in particular to a radio frequency power amplifier circuit with high and low power output channels, stable performance, high efficiency and relatively simple circuit. Background technique [0002] The RF power amplifier is an indispensable circuit module in the wireless communication system. It is mainly responsible for amplifying the modulated RF signal to a certain power value and then transmitting it through the antenna. In the TD-SCDMA / CDMA / WCDMA system, the output power of the RF power amplifier is not always maintained at the maximum value. In order to optimize the cell capacity (the amount of transmission that the base station can handle simultaneously), each mobile phone needs to control its RF output power so that The base station maintains the same effective receive SNR for each handset. From the probability distribution of the average output power of most mobi...

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Problems solved by technology

[0005] The present invention aims to solve the problems in the prior art that the high and low power synthesis circuits of radio frequency power amplifiers affect the low power mode efficiency of radio frequency power amplifiers due to switch insertion loss and other reasons, resulting in low average efficiency, complex matching network circuits and difficult design , and then provide a high and low power combining circuit of RF power amplifier with stable performance, high average efficiency and relatively simple circuit

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