A protection circuit for HBT RF Power Amplifier under load mismatch conditions

Karoui, W.; Parra, T.

doi:10.1109/newcas.2008.4606366

Cited by 13 publications

(14 citation statements)

References 6 publications

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“…Characterization of antenna mismatch may provide a maximum VSWR, such that the antenna will never exceed certain  max under mismatch effects [1][2][3][4][5][6][7][8]. If this value can be estimated, the two factors  and µ' [39] (instead of k LS and  LS ) may be especially useful to predict the possible instability under a particular  max .…”

Section: Potential Instability Analysis Under Mismatch Effectsmentioning

confidence: 99%

“…Power amplifier (PA) designs, which are stable under ideal 50  terminations, may become unstable [1][2][3][4][5] under antenna mismatch conditions in realistic wireless environments, such as where the antenna input impedance is affected by objects in its vicinity [1][2][3][4][5][6][7][8]. Therefore, evaluation of the stability robustness against load mismatches is essential for reliable operation.…”

Section: Introductionmentioning

confidence: 99%

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Stability Analysis of Power Amplifiers Under Output Mismatch Effects

Suárez

Ramírez

Sancho

2014

IEEE Trans. Microwave Theory Techn.

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1 Abstract -Novel criteria are presented for small-and large-signal stability analysis of microwave circuits under output mismatch effects. They are based on concepts from bifurcation theory, which enable the derivation of general equations for the stability boundaries that depend on the termination load. The boundary calculation does not require any optimization of the circuit parameters. Instead, it is based on the direct calculation of an admittance function obtained through circuit linearization about either the dc solution, in the small-signal stability analysis, or the periodic solution, in the large-signal one, with low computational cost. As will be demonstrated both with homotopy and bifurcation concepts, the Hopf locus obtained in this way delimits a stable region and a potentially unstable one. In a large-signal stability analysis, the sidebands that influence the stability properties are identified, which depend on the particular amplifier topology and its filtering effects. The stability boundaries are then calculated with the conversion matrix approach for all load impedance values at the relevant harmonic and sideband frequencies. For the derivation of absolute stability conditions, a new scattering type matrix is proposed describing the circuit response from the output reference plane with respect to the two sidebands about the input carrier. The new methodologies and formulations have been validated by independent simulations using pole-zero identification, and by measurements.

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Section: Potential Instability Analysis Under Mismatch Effectsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Stability Analysis of Power Amplifiers Under Output Mismatch Effects

Suárez

Ramírez

Sancho

2014

IEEE Trans. Microwave Theory Techn.

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“…The PA can be damaged when a load mismatch occurs, therefore the PA's ruggedness was a main concern for Tx chain in mobile handsets. For this reason, many efforts were made to improve it and solutions for sufficient ruggedness were provided [1][2][3][4][5][6][7][8][9][10][11][12][13], including: Clamping circuit [1][2][3], resistive emitter ballasting [4], closed loop protection technique [1,[5][6][7][8][9][10], high voltage process, and so on. A general ruggedness requirement for PA-duplexer (PAD) modules is to have no damage or permanent performance degradation with a full RF input power drive under high load VSWR conditions at a maximum supply voltage.…”

Section: Introductionmentioning

confidence: 99%

A Ruggedness Improved Mobile Radio Frequency Power Amplifier Module with Dynamic Impedance Correction by Software Defined Atomization

Jeon¹,

Kang

2019

Electronics

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A ruggedness improved multi-band radio frequency (RF) power amplifier (PA) module applicable to mobile handsets, which are required to survive against a serious load impedance change under extreme power and bias conditions, is presented. In this method, the load impedance of PA is adaptively adjusted with a digitally controlled impedance corrector to keep the PA safe by performing a load mismatch detection. The impedance mismatch detector, impedance corrector, and other RF switches were all integrated into a single integrated circuit (IC) using silicon on insulator (SOI) complementary metal oxide semiconductor (CMOS). For the verification purpose, a 2-stage hetero junction bipolar transistor (HBT) PA module adopting this method was fabricated. At a frequency of 1915 MHz, a collector bias voltage of 4.2 V, and over a wider range of load impedance variation between a VSWR of 1 and a VSWR of 5.5, it did not fail. When this technique was not applied with a voltage standing wave ratio (VSWR) range of 1 to 4, it resulted in an acceptable RF performance degradation of 1% power added efficiency (PAE) in envelope tracking (ET) mode. Moreover, it survived at a bias voltage 1V larger than when the technique was not applied for the same mismatch condition.

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“…Several approaches have been developed to prevent solid state PAs from being damaged against load mismatch. In previous generations of handsets, it was general to implement an isolator between the PA module and the handset antenna in order to isolate the amplifier from changes in impedance at the antenna port, which is incompatible with modern handsets due to the size and cost limits [1]. Other solutions including improved process [2,3], resistive emitter ballasting [4], and various open-loop/closed-loop techniques [5][6][7][8][9][10][11][12] have been proposed.…”

Section: Introductionmentioning

confidence: 99%

Software-Based Adaptive Protection Control against Load Mismatch for a Mobile Power Amplifier Module

Jeon¹,

Jung

Kang

2019

Electronics

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A closed-loop protection method for a radio frequency (RF) power amplifier (PA) module applicable to mobile handsets has been introduced. The load impedance of the PA was adaptively sensed by an embedded impedance detector which was digitally controlled and the system adjusted PA power using a feedback circuit to keep the PA safe based on a load mismatch detection. For verification, a two-stage hetero junction bipolar transistor (HBT) PA module for handsets was fabricated and tested against load mismatch. Measurement results showed that the technique could help PA survive at a 0.5V larger collector bias voltage condition than when the technique was not applied for the same mismatch condition with an acceptable RF performance degradation at nominal condition.

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A protection circuit for HBT RF Power Amplifier under load mismatch conditions

Cited by 13 publications

References 6 publications

Stability Analysis of Power Amplifiers Under Output Mismatch Effects

Stability Analysis of Power Amplifiers Under Output Mismatch Effects

A Ruggedness Improved Mobile Radio Frequency Power Amplifier Module with Dynamic Impedance Correction by Software Defined Atomization

Software-Based Adaptive Protection Control against Load Mismatch for a Mobile Power Amplifier Module

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