Dual-mode power amplifier system with transformer

Abstract

The invention provides a dual-mode power amplifier system with a transformer. A power amplifier system in accordance with an example embodiment can utilize a transformer having a primary winding inductively coupled to a secondary winding, where the primary winding includes a center tap between a first port and a second port, where the secondary winding includes a third port and a fourth port, where the primary winding receives a first output from a first amplifier, where the center tap receives a second output from a second amplifier. The system can also include a first capacitor connected to the center tap and the first port; a second capacitor connected to the center tap and the second port; a first switch in electrical connection with the center tap, where the first switch can connect the center tap to a ground port; a second switch connected to the fourth port, where the second switch can connect the fourth port to a common node in electrical connection with the center tap; and a third capacitor connected between the common node and an output node connected to the third port from a system output can be obtained.

Description

technical field [0001] Embodiments of the present invention generally relate to power amplifiers, and more particularly, to a system and method of low power mode amplification with transformer output matching and virtual ground. Background technique [0002] A power amplifier does not need to be at a fixed output power to operate. Typically, power amplifiers are used at low output power backed off from their peak output power. However, simply backing off the power amplifier wastes current by using more current than needed. Therefore, a separate amplification path for low output power operation is urgently needed so that the current conduction is reduced. [0003] However, the isolation between high-power and low-power modes is often incomplete, leaving each mode out of optimum condition, reducing performance. Isolation switches can be used for isolation purposes. However, the operation of power amplifiers usually produces large voltage swings, and if the voltage swings e...

AI Technical Summary

Problems solved by technology

However, figure 1 The high output power of amplifier 101 in high power mode produces high voltage swings at the output, and the operation of switch 103 is under high voltage stress, often exceeding the limits of the safe operating range of switch 103 for a given device

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