Angel V. Peterchev

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This paper discusses the presence of steady-state limit cycles in digitally controlled pulse-width modulation (PWM) converters, and suggests conditions on the control law and the quantization resolution for their elimination. It then introduces single-phase and multi-phase controlled digital dither as a means of increasing the effective resolution of(More)
This paper develops the architecture of a digital PWM controller for application in multi-phase voltage regulation modules (VRM’s) with passive current sharing. In this context, passive current sharing and VRM transient response are analyzed. A scheme for sensing a combination of the VRM output voltage and output current with a single lowresolution windowed(More)
This paper describes a dual-mode digitally controlled buck converter IC for cellular phone applications. An architecture employing internal power management is introduced to ensure voltage compatibility between a single-cell lithium-ion battery voltage and a low-voltage integrated circuit technology. Special purpose analog and digital interface elements are(More)
BACKGROUND Various transcranial magnetic stimulation (TMS) coil designs are available or have been proposed. However, key coil characteristics such as electric field focality and attenuation in depth have not been adequately compared. Knowledge of the coil focality and depth characteristics can help TMS researchers and clinicians with coil selection and(More)
BACKGROUND The growing use of transcranial electric and magnetic (EM) brain stimulation in basic research and in clinical applications necessitates a clear understanding of what constitutes the dose of EM stimulation and how it should be reported. METHODS This paper provides fundamental definitions and principles for reporting of dose that encompass any(More)
A consistent framework for load-line regulation design is presented, applicable to microprocessor voltage regulators (VRs) using either electrolytic or ceramic output capacitors. With conventional feedback control, the loop bandwidth is limited by stability constraints linked to the switching frequency. The output capacitor has to be chosen sufficiently(More)
We present the first computational study investigating the electric field (E-field) strength generated by various electroconvulsive therapy (ECT) electrode configurations in specific brain regions of interest (ROIs) that have putative roles in the therapeutic action and/or adverse side effects of ECT. This study also characterizes the impact of the white(More)
A four-phase integrated buck converter in 45 nm silicon-on-insulator (SOI) technology is presented. The controller uses unlatched pulse-width modulation (PWM) with nonlinear gain to provide both stable small-signal dynamics and fast response ( 700 ps) to large input and output transients. This fast control approach reduces the required output capacitance by(More)