-
[show abstract]
[hide abstract]
ABSTRACT: Gastrointestinal stromal sarcomas (GISTs) are the most common mesenchymal tumours originating in the digestive tract. These tumours have become a model of multidisciplinary work in oncology: the participation of several specialities (oncologists, pathologists, surgeons, molecular biologists, radiologists and others) has allowed advances in the understanding of this tumour and the consolidation of a targeted therapy, imatinib, as the first molecular treatment that is efficacious in solid tumours. Following the introduction of this drug, median survival of patients with advanced stage GIST has gone from 18 to more than 60 months. Therapy planning of GIST must be considered within a multidisciplinary context, and it is advisable that it takes place in reference centres for the care of sarcomas and GIST participating in clinical trials.
Clinical and Translational Oncology 07/2012; 14(7):536-40. · 1.33 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: This paper explores the modulation bandwidth limits for switching amplifiers, by analyzing the fundamental tracking capabilities of two-level switching signals. With this aim, this work synthesizes two-level switching signals by obtaining the distribution of switching events providing both minimum average switching frequency and inband-error-free encoding, targeting to minimize the amplifier switching losses when tracking a generic bandlimited signal. This analysis also provides a framework reference to characterize the deviation from such limit in modulations used in actual amplifiers.
Circuits and Systems I: Regular Papers, IEEE Transactions on 11/2011; · 1.97 Impact Factor
-
S B Kaye,
N Colombo,
B J Monk,
S Tjulandin,
B Kong,
M Roy,
S Chan,
E Filipczyk-Cisarz,
H Hagberg,
I Vergote,
C Lebedinsky,
T Parekh,
P Santabárbara,
Y C Park,
A Nieto, A Poveda
[show abstract]
[hide abstract]
ABSTRACT: OVA-301 is a large randomized trial that showed superiority of trabectedin plus pegylated liposomal doxorubicin (PLD; CentoCor Ortho Biotech Products L.P., Raritan, NJ, USA). over single-agent PLD in 672 patients with relapsed ovarian cancer, particularly in the partially platinum-sensitive subgroup [platinum-free interval (PFI) of 6-12 months]. This superiority has been suggested to be due to the differential impact of subsequent (platinum) therapy.
a detailed analysis of subsequent therapies and survival outcomes in the overall population and in the subsets according to platinum sensitivity was therefore conducted.
similar proportions of patients received subsequent therapy in each arm (76% versus 77%), including further platinum-based regimens (49% versus 55%). Patients in the trabectedin/PLD arm received subsequent chemotherapy at a later time (median delay 2.5 months versus PLD arm). Overall survival from subsequent platinum was significantly prolonged in the partially platinum-sensitive disease subset (hazard ratio = 0.63; P = 0.0357).
the superiority of trabectedin/PLD over single-agent PLD in OVA-301 cannot be explained by differences in the extent or nature of subsequent therapies administered to these patients. On the other hand, these exploratory analyses support the hypothesis that the enhanced survival benefits in the partially platinum-sensitive subset might be due to an extended PFI leading to longer survival with subsequent platinum.
Annals of Oncology 01/2011; 22(1):49-58. · 6.43 Impact Factor
-
A Poveda,
I Vergote,
S Tjulandin,
B Kong,
M Roy,
S Chan,
E Filipczyk-Cisarz,
H Hagberg,
S B Kaye,
N Colombo,
C Lebedinsky,
T Parekh,
J Gómez,
Y C Park,
V Alfaro,
B J Monk
[show abstract]
[hide abstract]
ABSTRACT: OVA-301 is a large randomized trial that showed superiority of trabectedin plus pegylated liposomal doxorubicin (PLD) over PLD alone in relapsed ovarian cancer. The optimal management of patients with partially platinum-sensitive relapse [6-12 months platinum-free interval (PFI)] is unclear.
within OVA-301, we therefore now report on the outcomes for the 214 cases in this subgroup.
Trabectedin/PLD resulted in a 35% risk reduction of disease progression (DP) or death [hazard ratio (HR) = 0.65, 95% confidence interval (CI), 0.45-0.92; P = 0.0152; median progression-free survival (PFS) 7.4 versus 5.5 months], and a significant 41% decrease in the risk of death (HR = 0.59; 95% CI, 0.43-0.82; P = 0.0015; median survival 23.0 versus 17.1 months). The safety of trabectedin/PLD in this subset mimicked that of the overall population. Similar proportions of patients received subsequent therapy in each arm (76% versus 77%), although patients in the trabectedin/PLD arm had a slightly lower proportion of further platinum (49% versus 55%). Importantly, patients in the trabectedin/PLD arm survived significantly longer after subsequent platinum (HR = 0.63; P = 0.0357; median 13.3 versus 9.8 months).
This hypothesis-generating analysis demonstrates that superior benefits with trabectedin/PLD in terms of PFS and survival in the overall population appear particularly enhanced in patients with partially sensitive disease (PFI 6-12 months).
Annals of Oncology 01/2011; 22(1):39-48. · 6.43 Impact Factor
-
D Fuster,
J R Ayuso, A Poveda,
R Cubedo,
A Casado,
J Martínez-Trufero,
A López-Pousa,
X G Del Muro,
F Lomeña,
J Maurel,
F Pons
[show abstract]
[hide abstract]
ABSTRACT: The aim of this study was to evaluate the utility of positron emission tomography with 18F-fluorodeoxyglucose (FDG-PET) in monitoring response in refractory GIST.
This multicenter study prospectively evaluated 21 patients with locally advanced and/or metastatic GIST refractory to with high-dose imatinib (800 mg/day) treated with doxorubicin 15-20 mg/m2/weekly for 4 cycles, followed by imatinib maintenance (400 mg/day). CT and FDG-PET were performed at baseline and after completion of therapy.
Mean baseline tumor size on CT was 5.9 cm. Median progression-free survival (PFS) was 219 days (range 62-1108). Three out of 21 patients (14%) had partial responses (PR) under RECIST criteria, 12 patients (57%) remained stable (SD) and 6 showed progression (PD) of the disease during treatment (29%). Six patients had PR by FDG-PET, 15 showed SD (n=9) or PD (n=6) based on EORTC criteria. Patients with a PFS <6 mo showed a significantly higher ∑SUVmax at baseline (26.04±13.4) than those with PFS≥6 mo (9.82±5.0) (P<0.05). A correlation was found between PET response and PFS: PR 14±6.1 mo, SD 5.5±0.8 mo and PD 3.5±4.1 mo (P<0.05). A residual SUVmax <5 after treatment correlated with improved PFS (314±315 days vs 131±91 days) (P<0.01). Survival curves showed a significant association between PET response and PFS (P<0.05). Patients with wild-type genotype KIT (KIT-WT) showed a significantly lower baseline SUVmax (5.36±1.4) than non-WT KIT (8.40±3.6) (P<0.05).
FDG-PET is useful in assessing response of GIST refractory to imatinib and correlates with the presence of KIT-WT. Baseline ∑SUVmax can predict response to treatment in this series.
The quarterly journal of nuclear medicine and molecular imaging: official publication of the Italian Association of Nuclear Medicine (AIMN) [and] the International Association of Radiopharmacology (IAR), [and] Section of the Society of... 12/2010; 55(6):680-7.
-
P Hoskins,
I Vergote,
A Cervantes,
D Tu,
G Stuart,
P Zola, A Poveda,
D Provencher,
D Katsaros,
B Ojeda, [......],
L Elit,
C Mendiola,
A Sugimoto,
V D'Hondt,
A Oza,
J R Germa,
M Roy,
L Brotto,
D Chen,
E A Eisenhauer
[show abstract]
[hide abstract]
ABSTRACT: Topotecan has single-agent activity in recurrent ovarian cancer. It was evaluated in a novel combination compared with standard frontline therapy.
Women aged 75 years or younger with newly diagnosed stage IIB or greater ovarian cancer, Eastern Cooperative Oncology Group Performance Status of 1 or less, were stratified by type of primary surgery and residual disease, treatment center, and age; then randomly assigned to one of the two 21-day intravenous regimens. Patients in arm 1 (n = 409) were administered four cycles of cisplatin 50 mg/m(2) on day 1 and topotecan 0.75 mg/m(2) on days 1-5, then four cycles of paclitaxel 175 mg/m(2) over 3 hours on day 1 followed by carboplatin (area under the curve = 5) on day 1. Patients in arm 2 (n = 410) were given paclitaxel plus carboplatin as in arm 1 for eight cycles. We compared progression-free survival (PFS), overall survival, and cancer antigen-125 normalization rates in the two treatment arms. A stratified log-rank test was used to assess the primary endpoint, PFS. All statistical tests were two-sided.
A total of 819 patients were randomly assigned. At baseline, the median age of the patients was 57 years (range = 28-78); 81% had received debulking surgery, and of these, 55% had less than 1 cm residual disease; 66% of patients were stage III and 388 (47.4%) patients had measurable disease. After a median follow-up of 43 months, 650 patients had disease progression or died without documented progression and 406 had died. Patients in arm 1 had more hematological toxicity and hospitalizations than patients in arm 2; PFS was 14.6 months in arm 1 vs 16.2 months in arm 2 (hazard ratio = 1.10, 95% confidence interval = 0.94 to 1.28, P = .25). Among patients with elevated baseline cancer antigen-125, fewer in arm 1 than in arm 2 had levels return to normal by 3 months after random assignment (51.6% vs 63.3%, P = .007)
Topotecan and cisplatin, followed by carboplatin and paclitaxel, were more toxic than carboplatin and paclitaxel alone, but without improved efficacy. Carboplatin plus paclitaxel remains the standard of care for advanced epithelial ovarian cancer.
CancerSpectrum Knowledge Environment 10/2010; 102(20):1547-56. · 14.07 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: This work extends the Asynchronous ΣΔ Modulator and its Adaptive version to multi-level modulators, targeting wideband high-efficiency switching power amplifiers. The performance of these modulators is compared with the multi-level Pulse Width Modulator, the most common modulator in multilevel switching power amplifiers. Behavioural model simulation results show that, unlike the multi-level PWM (which can only be used at high switching frequencies), the Asynchronous ΣΔ Modulators can also be used at average switching frequencies close to the signal bandwidth. At high switching frequencies, the performance of all the modulators is similar. The Asynchronous ΣΔ Modulators have further and more important advantages, such as high PSRR (even at the input signal frequency), the ability of handling non-regular distributed voltage levels, or a low ratio between the average switching frequency and the maximum instantaneous switching frequency.
Control and Modeling for Power Electronics (COMPEL), 2010 IEEE 12th Workshop on; 07/2010
-
[show abstract]
[hide abstract]
ABSTRACT: This work proposes a switching policy for multi-level full-bridge switching power converters and analyses their performance by driving them with a multi-level PWM modulation, targeting high-efficiency power amplifiers. Unlike conventional policies, which generate the output voltage levels only from the values of the supply voltages, this enhanced policy also uses the values of the voltage difference between supply voltages to generate additional output voltage levels, therefore maximising the number of output voltage levels for a given set of supply voltages and connection switches. Simulation results show that, when tracking a band-limited signal, the proposed switching policy can reduce the power of the high-frequency spectral content from 21% to 11% by upgrading a 5-level amplifier to a 7-level amplifier without adding supply voltages or connection switches.
Circuits and Systems (ISCAS), Proceedings of 2010 IEEE International Symposium on; 07/2010
-
[show abstract]
[hide abstract]
ABSTRACT: This paper deals with the proposal of a new topology for a g<sub>m</sub>-C continuous time filter which allows the adjustment and tuning of its characteristic parameters (ω<sub>O</sub> and Q) in an independent way (without cross-tuning), thereby extending the Q range of the filter for a particular ω<sub>O</sub> value. Additionally a comparison of three different Q-tuning algorithms is presented. It is shown that an LMS-based Q-control strategy allows to overcome the intrinsic dependence between the Q and ω<sub>O</sub> tuning loops. The combination of both the proposed filter topology and the selected control loop algorithms results in an enhanced transient performance as well as an improvement in terms of cross-detuning.
Circuits and Systems (ISCAS), Proceedings of 2010 IEEE International Symposium on; 07/2010
-
J Martin-Broto,
A Gutierrez,
X Garcia-del-Muro,
J A Lopez-Guerrero,
J Martinez-Trufero,
L M de Sande,
N Lainez,
J Maurel,
A De Juan,
F Losa, [......],
A Casado,
P G Tejido,
R Blanco,
J Carles,
J Bellmunt,
A Gomez-España,
R Ramos,
J Martinez-Serra,
A Llombart-Bosch, A Poveda
[show abstract]
[hide abstract]
ABSTRACT: To assess whether deletions involving codons 557 and/or 558 (critical deletions) of exon 11 of KIT are relevant in the prognosis of relapse-free survival (RFS) in gastrointestinal stromal tumor (GIST) patients with a long follow-up.
A univariate and multivariate analysis for RFS were carried out on 162 localized GIST patients over the entire follow-up period and over the intervals 0-4 years and >4 years. Factors assessed among others were Fletcher/National Institutes of Health and Miettinen-Lasota/Armed Forces Institute of Pathology (M-L/AFIP) risk categories, critical deletions and non-deletion-type mutation (NDTM) within exon 11 of KIT.
Multivariate analyses revealed that M-L/AFIP [relative risk (RR) 11.45, confidence interval (CI) 4.40-29.76, for the high-risk subgroup and RR 5.97, CI 2.09-17.06, for the intermediate subgroup] and critical deletions (RR 3.05, CI 1.59-5.85) were independent prognostic factors for RFS for the first 4 years and for the entire follow-up period. Beyond 4 years, the high-risk M-L/AFIP subgroup (RR 8.12, CI 1.48-44.4) and NDTM (RR 6.42, CI 1.17-35.12) were independent prognostic factors for RFS. The median follow-up was 84 months.
Critical deletions represent a time-dependent prognostic factor limited to the first 4 years after surgery, which could help identify a subset with higher and earlier risk for relapse in GIST patients.
Annals of Oncology 03/2010; 21(7):1552-7. · 6.43 Impact Factor
-
S Pecorelli,
I Ray-Coquard,
O Tredan,
N Colombo,
G Parma,
G Tisi,
D Katsaròs,
C Lhommé,
A A Lissoni,
J B Vermorken,
A du Bois, A Poveda,
L Frigerio,
P Barbieri,
P Carminati,
S Brienza,
J P Guastalla
[show abstract]
[hide abstract]
ABSTRACT: A prospective phase II study was conducted to evaluate the efficacy and toxicity of oral gimatecan in patients with recurrent epithelial ovarian, fallopian tube or peritoneal cancer.
Patients had a maximum of three prior chemotherapy lines with no more than two prior platinum-containing regimens and a progression-free interval after the last dose of platinum <12 months. A total dose of 4 mg/m(2)/cycle (0.8 mg/m(2)/day from day 1 to day 5) was administered, repeated every 28 days.
From June 2005 to December 2005, 69 assessable patients were enrolled. The best overall response to study treatment by combined CA-125 and RECIST criteria was partial response in 17 patients (24.6%) and disease stabilization in 22 patients (31.9%). The median time to progression and overall survival were 3.8 and 16.2 months, respectively. A total of 312 cycles were administered. Neutropenia grade 4 and thrombocytopenia grade 4 occurred in 17.4% and 7.2% of patients, respectively. Diarrhea grade 4 was never observed. Asthenia and fatigue were reported by 36.2% and 18.8% of patients, but were all grade 2 or less.
Gimatecan is a new active agent in previously treated ovarian cancer with myelosuppression as main toxicity.
Annals of Oncology 11/2009; 21(4):759-65. · 6.43 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: This randomized, open-label, phase II clinical trial evaluated the optimal regimen of trabectedin administered every 3 weeks in patients with platinum-sensitive, relapsed, advanced ovarian cancer (AOC).
Patients previously treated with less than two or two previous chemotherapy lines were randomized to receive trabectedin 1.5 mg/m(2) 24 h (arm A, n = 54) or 1.3 mg/m(2) 3 h (arm B, n = 53). Objective response rate (ORR) per RECIST was the primary efficacy end point. Toxic effects were graded according to the National Cancer Institute-Common Toxicity Criteria v. 2.0.
ORR was 38.9% [95% confidence interval (CI) 25.9% to 53.1%; arm A] and 35.8% (95% CI 23.1% to 50.2%; arm B) (intention-to-treat primary analysis). Median time to progression was 6.2 months (95% CI 5.3-8.6 months; arm A) and 6.8 months (95% CI 4.6-7.4 months; arm B). Frequent severe adverse events were nausea/vomiting (24%, arm A; 15%, arm B) and fatigue (15%, arm A; 10%, arm B). Common severe laboratory abnormalities were transient, noncumulative neutropenia (55%, arm A; 37%, arm B) and transaminase increases (alanine aminotransferase, 55%, arm A; 59%, arm B).
Both every-3-weeks trabectedin regimes, 1.5 mg/m(2) 24 h and 1.3 mg/m(2) 3 h, were active and reasonably well tolerated in AOC platinum-sensitive patients. Trabectedin every-3-weeks has promising activity and deserves to be further evaluated in relapsed AOC.
Annals of Oncology 07/2009; 20(11):1794-802. · 6.43 Impact Factor
-
N S Reed,
C Mangioni,
H Malmström,
G Scarfone, A Poveda,
S Pecorelli,
S Tateo,
M Franchi,
J J Jobsen,
C Coens,
I Teodorovic,
I Vergote,
J B Vermorken
[show abstract]
[hide abstract]
ABSTRACT: The management of uterine sarcomas continues to present many difficulties. Primary surgery is the optimal treatment but the role of post-operative radiation remains uncertain. In the mid-1980s, the European Organisation for Research and Treatment of Cancer Gynaecological Cancer Group Study proposed a trial to evaluate adjuvant radiotherapy, as previous non-randomised studies had suggested a survival advantage and improved local control when post-operative radiation was administered. The study opened in 1987 taking 13 years to accrue 224 patients. All uterine sarcoma subtypes were permitted. Patients were required to have undergone as a minimum, TAH and BSO and wahsings (166 patients) but nodal sampling was optional. There were 103 leiomyosarcomas (LMS), 91 carcinosarcomas (CS) and 28 endometrial stromal sarcomas (ESS). Patients were randomised to either observation or pelvic radiation, 51 Gy in 28 fractions over 5 weeks. Hundred and twelve were recruited to each arm. The initial analysis has shown a reduction in local relapse (14 versus 24, p=0.004) but no effect on either OS or PFS. No unexpected toxicity was seen in the radiation arm. No difference in either overall or disease-free survival was demonstrated but there is an increased local control for the CS patients receiving radiation but without any benefit for LMS. Prognostic factor analysis shows that stage, age and histological subtype were important predictors of behaviour which may explain differences between CS and LMS. CS appears to show more kinship to poorly differentiated endometrial carcinomas in behaviour. LMS did not show the same benefit from radiation. These results will help shape future management and clinical trials in uterine sarcomas.
European Journal of Cancer 05/2008; 44(6):808-18. · 5.54 Impact Factor
-
A Poveda,
R Salazar,
J M del Campo,
C Mendiola,
J Cassinello,
B Ojeda,
J A Arranz,
A Oaknin,
J García-Foncillas,
M J Rubio,
A González Martín
[show abstract]
[hide abstract]
ABSTRACT: Ovarian and cervical cancers are significant health problems. This article provides an update in selected management topics. Paclitaxel and platinum derivatives are the first-line treatment for patients with advanced disease. In selected patients, intraperitoneal chemotherapy has been associated with improved survival but the broad applicability of this strategy is limited by issues of toxicity and feasibility. Management of patients with recurrent disease is based on a number of factors and includes surgery in selected cases, platinum-based chemotherapy for patients with platinum-sensitive disease and other agents such as topotecan and pegylated liposomal formulation of doxorubicin for patients with platinum-resistant disease. In cervical cancer, the most significant issue/event is the demonstration of superior survival with topotecan and cisplatin compared to cisplatin alone. Finally, new agents such as epidermal growth factor receptor inhibitors and antiangiogenic agents are being currently tested in these settings.
Clinical and Translational Oncology 08/2007; 9(7):443-51. · 1.33 Impact Factor
-
A L|[oacute]|pez-Pousa,
R Losa,
J Mart|[iacute]|n,
J Maurel,
J Fra,
M Sierra,
A Casado,
J Garc|[iacute]|a del Muro, A Poveda,
C Bala|[ntilde]||[aacute,
J Mart|[iacute]|nez-Trufero,
E Esteban,
J M Buesa
[show abstract]
[hide abstract]
ABSTRACT: Materials and methods Results Discussion References Acknowledgements Figures and TablesThe aim of the study was to determine the dose-limiting toxicity and maximum tolerated dose of a first-line combination of doxorubicin and gemcitabine in adult patients with advanced soft tissue sarcomas and to explore its activity and toxicity, and the presence of possible interactions between these agents. Patients with measurable disease were initially treated with doxorubicin 60 mg m-2 by i.v. bolus on day 1 followed by gemcitabine at 800 mg m-2 over 80 min on days 1 and 8, every 21 days. Concentrations of gemcitabine and 2',2'-difluorodeoxyuridine in plasma, and gemcitabine triphosphate levels in peripheral blood mononuclear cells were determined during 8 h after the start of gemcitabine infusion. Myelosuppression and stomatitis were limiting toxicities, and the initial dose level was applied for the Phase II trial, where grade 3–4 granulocytopenia occurred in 70% of patients, grade 3 stomatitis in 46% and febrile neutropenia in 20%. Objective activity in 36 patients was 22% (95% CI: 9–35%), and a 50% remission rate was noted in leiomyosarcomas. Administration of doxorubicin preceding gemcitabine significantly reduced the synthesis of gemcitabine triphosphate. Clinical activity, similar to that of single-agent doxorubicin, and the toxicity encountered do not justify further studies with this schedule of administration.Keywords: doxorubicin, gemcitabine, soft tissue sarcoma, gemcitabine triphosphate
British Journal of Cancer 05/2006; 94(12):1797-1802. · 5.04 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Successful on-chip integration of a buck switching power converter for battery-operated portable applications concurrently requires fulfilling stringent specifications, namely low silicon area occupancy, low relative output ripple, proper transient response whilst assuring high efficiency for a wide range of load currents. This latter key characteristic of high efficiency can be achieved not only by the power plant design but by the use of proper control methods. This work focuses in efficiency optimization of a buck converter suited to CMOS integration. Switching and conduction energy loss models are first discussed both for continuous and discontinuous conduction modes. Minimization of overall power losses yields an optimum law that continuously tunes the switching frequency as a function of load current. Being one of the simplest control methods applied to a buck converter the output voltage hysteretic control, the work then focuses in the implicit switching frequency tuning that results from the application of this control method and its impact on overall power efficiency. The paper contrasts the analytical models for the frequency variation, matched with system-level simulations, when including as non-idealities both output capacitor ESR and control delay. It is observed that for low output current values, the output voltage hysteretic control provides quasi-optimum power efficiency. Design criteria for matching both explicit optimum law and the law implicit in hysteretic control are provided, and a design procedure including output voltage ripple and capacitor value is discussed. Numerical examples throughout the paper consider a standard CMOS 0.35 mum technology. Experimental results for a low frequency prototype demonstrate the implicit switching frequency modulation of the output voltage hysteretic control
Power Electronics Specialists Conference, 2005. PESC '05. IEEE 36th; 07/2005
-
[show abstract]
[hide abstract]
ABSTRACT: The design and implementation of a CMOS analog integrated circuit that provides multi-mode control laws for high-frequency switching power converters is described. The general-purpose controller circuit is capable of implementing classical PWM control, current-mode control with compensating ramp, sliding-mode control and one-cycle control. The main building block within the controller architecture is the current conveyor. Additionally, the IC includes power MOSFETs and their drivers. Layout details for a CMOS 0.35 μm technology implementation are discussed.
Circuits and Systems, 2005. ISCAS 2005. IEEE International Symposium on; 06/2005
-
[show abstract]
[hide abstract]
ABSTRACT: This work presents a model to determine the power consumption of tapered buffers, validating its results with transistor-level simulations. Focusing on their application as gate drivers for high-frequency on-chip switching power converters, the need for a fall-rise time evaluation at the output of the tapered buffer is discussed. Consequently, the output fall-rise time is modeled and validated by means of simulations. Given the linear relation between the fall-rise time and the switching losses of the power MOSFET, an optimized design procedure is proposed to concurrently minimize the switching losses of the tapered buffer together with the power MOSFET switching losses. The work concludes with a design example for a 15000 μm-width PMOS transistor, presenting an optimum tapering factor of 21, for a specific 0.35 μm standard CMOS technology.
Circuits and Systems, 2005. ISCAS 2005. IEEE International Symposium on; 06/2005
-
[show abstract]
[hide abstract]
ABSTRACT: Successful on-chip integration of a buck switching power converter concurrently requires the fulfillment of stringent specifications, namely low silicon area occupancy, low relative output ripple, proper transient response, whilst assuring high efficiency. The paper focuses on efficiency optimization of a buck converter suited to CMOS integration. Switching and conduction energy loss models are discussed, both for continuous and discontinuous conduction modes. Minimization of overall power losses yields an optimum law that continuously tunes the switching frequency as a function of load current. A practical piecewise linear approximation is proposed and applied to transient simulations and to compute overall efficiency. The work concludes by comparing the efficiency-oriented optimum frequency tuning law to that intrinsically obtained from output voltage hysteretic control. Numerical examples consider a standard CMOS 0.35 μm technology.
Circuits and Systems, 2005. ISCAS 2005. IEEE International Symposium on; 06/2005
-
A du Bois,
M Quinn,
T Thigpen,
J Vermorken,
E Avall-Lundqvist,
M Bookman,
D Bowtell,
M Brady,
A Casado,
A Cervantes, [......],
J Rochon,
G Rustin,
S Sagae,
F Stehman,
G Stuart,
E Trimble,
P Vasey,
I Vergote,
R Verheijen,
U Wagner
Annals of Oncology 02/2005; 16 Suppl 8:viii7-viii12. · 6.43 Impact Factor
