Writing Engineering Abstracts(32)

8/7/2019 Writing Engineering Abstracts(32)

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Writing Engineering Abstracts(32)

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:(+)


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(1 of 2)(+) Lengthening the usage timeof portable devices depends on the ability to increase theconversion efficiency of a PWM DC/DC converter, which isa critical index for converter performance. As non-overlapping time of the control signal in the converter

switches significantly impacts the efficiency of DC/DCconverters, an excessive amount of time will increase ther ipp le o f ou tpu t o r genera te a cu r ren t sp i ke .Correspondingly, an insufficient amount of time lowersefficiency or destroys the switches when turned on

simultaneously. Therefore, this work describes anovel feedback control loop, capable of modifyingautomatically the non-overlapping time when process,temperature or supply voltage varies.


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(2 of 2)A preliminary non-overlapping time is set. The controlsignal of switches and node-voltage of LX are thendetected by a detection circuit, followed by shortening ofthe non-overlapping time sequentially. Otherwise, the non-overlapping time is increased if an insufficient time leads to

simultaneous turning on of the two switches. Analysis results indicate that the proposed feedbackcontrol loop increases power conversion efficiency by 1-3%. In addition to reducing the extent towhich the ambient environment affects PWM Dc-to-Dc

converter, the proposed control loop increases productyield.


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(1 of 2) (+) Designing a currentcontroller without a slope compensator can increaseproduct applications. Whereas a current controller containsa slope compensator to ensure that the duty cycle exceeds0.5, variation among exterior components can lead to

insufficiency or excessiveness of the slope compensator,subsequently incurring system instability. Therefore,this work presents a novel current controller, capable ofenhancing dc-dc converter performance and simplifyingcompensator design. Various ways in which the

electric current limits the current controller are analyzed.Factors that influence compensator control are thenidentified. Next, whether circuit design can consider theentire electrical circuit is determined as well.


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(2 of 2) Analytical results indicate that theproposed current controller reduces the slope compensator,subsequently increasing duty cycle applications by 50%. Given its ability to reduce instability, theproposed controller increases dc-dc converter stability and

widens the scope of applications for electric currentcontrollers, in which the inductance value yields change.


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Writing Engineering Abstracts(32)