Power Amplifier Module Using Bipolar Attenuation Control
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Solution Overview
Problem
The use of field effect transistors (FETs) in attenuators within power amplifier modules increases manufacturing costs when combined with bipolar transistors, as existing solutions do not effectively employ bipolar transistors for attenuation control.
Innovation Solution
A power amplifier module design that utilizes bipolar transistors for both amplification and attenuation, with a second bipolar transistor controlled by a control voltage to manage signal attenuation, along with resistors and capacitors to regulate the RF signal, allowing for cost-effective implementation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a field effect transistor (FET) is used in the attenuator, then the attenuation control is achieved, but the manufacturing cost increases due to mixing bipolar transistors and FETs
Solution Approach 1:
The patent applies homogeneity by using bipolar transistors for both the amplification transistor (Q1) and the attenuator transistor (Q2), eliminating the need to mix different transistor types (bipolar and FET) in the same circuit. This uniform use of bipolar transistors simplifies manufacturing processes and reduces costs while maintaining the required functionality of both amplification and attenuation control.
2Ease of manufacture
If a bipolar transistor is used for both amplification and attenuation, then the manufacturing cost is reduced, but the control mechanism becomes more complex
Solution Approach 1:
The patent segments the control mechanisms for the two bipolar transistors: the amplification transistor (Q1) is controlled by a bias voltage that adjusts its gain, while the attenuator transistor (Q2) is controlled by a separate control voltage that adjusts the attenuation amount. This segmentation of control functions allows each transistor to be independently optimized and controlled, simplifying the overall control mechanism despite using the same transistor type.
Solution Approach 2:
The patent introduces a resistor (R1) as an intermediary element in the control path of the attenuator transistor (Q2). The resistor R1 is connected between the control voltage source and the base of Q2, serving as a mediator that regulates the control signal and enables precise attenuation control. This intermediary component simplifies the control mechanism by providing a straightforward voltage division and control pathway.
Data Source
AI summary
A power amplifier module includes a first bipolar transistor configured to amplify a radio frequency signal and output an amplified signal and a second bipolar transistor. A base of the second bipolar transistor is supplied with a control voltage for controlling attenuation of the radio frequency signal, and a collector the second bipolar transistor is supplied with a source voltage. The power amplifier module also includes a first resistor, where one end of the first resistor is connected to a supply path of the radio frequency signal to the first bipolar transistor, and a capacitor, where one end of the capacitor is connected to the other end of the first resistor and the other end of the capacitor is connected to the collector of the second bipolar transistor.