Combined control of drain video bandwidth and stability margins in power amplifiers for envelope tracking applications

Pelaz, Joana; Collantes, J.M.; Otegi, N.; Anakabe, A.; Collins, Gayle

doi:10.1109/mwsym.2014.6848420

Cited by 6 publications

(19 citation statements)

References 5 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In [30] and [31], experimental techniques were developed to characterize and modify the LF dynamics in amplifiers. These were based on the introduction of specific RF observation ports in the bias lines.…”

mentioning

confidence: 99%

“…From reflection measurements at those extra ports, the position and evolution of LF critical poles on the complex plane was obtained. However, there is an important limitation in [30] and [31] that prevents their direct application to the analysis of the LF dynamics in the presence of a large RF signal. The LF system poles obtained using [30], [31] correspond to a dc steady state fixed by a bias point when no input RF signal is applied.…”

mentioning

confidence: 99%

“…However, there is an important limitation in [30] and [31] that prevents their direct application to the analysis of the LF dynamics in the presence of a large RF signal. The LF system poles obtained using [30], [31] correspond to a dc steady state fixed by a bias point when no input RF signal is applied. These poles can be modified (shifted on the complex plane) by the large-signal RF power, affecting the LF characteristics of the circuit.…”

mentioning

confidence: 99%

“…These poles can be modified (shifted on the complex plane) by the large-signal RF power, affecting the LF characteristics of the circuit. This cannot be measured with the approach in [30] and [31] because, contrarily to what happens around the dc bias point, the large-signal steady state and its linearization can be affected by the connection of the vector network analyzer (VNA) at any of the observation ports. In addition, the approach described in [32] to characterize the poles in the presence of an input RF drive cannot be used for the observation of the LF resonances due to the poor sensitivity to the LF dynamics from RF ports.…”

mentioning

confidence: 99%

“…As a result, we need to connect the VNA to specific observation ports implemented in the bias paths in order to get enough sensitivity to capture the LF dynamics. However, we cannot use the approaches presented in [30] and [31] for that because consistency is not maintained between the test mode (the VNA connected at the port with its 50-impedance) and normal operation (in which observation ports are short circuited).…”

mentioning

confidence: 99%

See 4 more Smart Citations

Experimental Control and Design of Low-Frequency Bias Networks for Dynamically Biased Amplifiers

Pelaz

Collantes

Otegi

et al. 2015

IEEE Trans. Microwave Theory Techn.

Self Cite

View full text Add to dashboard Cite

To reach the video bandwidth requirements on the supply paths, power amplifiers with dynamic bias schemes are constrained to reduce the values of the low-frequency (LF) decoupling capacitors on their bias lines. This can entail a decrease of the LF stability margins, among other negative effects. In this work, a methodology is proposed to experimentally monitor and control the dominant poles that govern the LF dynamics of both gate and drain bias lines from dc to high compression power. A specific topology for the bias observation accesses allows a consistent characterization in large-signal regimes. An automatic procedure to trace root contours versus four control parameters is also developed. The complete approach can be used to optimize the design of the bias lines in terms of video bandwidth, relative stability margins, and bias voltage transfer function characteristics. Moreover, the design can account for the effect of the large-signal RF drive on these LF performances. The methodology is exemplified and validated in a demonstrator prototype specifically built for that purpose.

show abstract

mentioning

confidence: 99%

mentioning

confidence: 99%