Pahlevaninezhad M.,Queens University |
Drobnik J.,Freescale Inc. |
Jain P.K.,Queens University |
Bakhshai A.,Queens University
IEEE Transactions on Industrial Electronics | Year: 2012
This paper presents a load adaptive control approach to optimally control the amount of reactive current required to guarantee zero-voltage switching (ZVS) of the converter switches. The proposed dc/dc converter is used as a battery charger for an electric vehicle (EV). Since this application demands a wide range of load variations, the converter should be able to sustain ZVS from full-load to no-load condition. The converter employs an asymmetric auxiliary circuit to provide the reactive current for the full-bridge semiconductor switches, which guarantees ZVS at turn-on times. The proposed control scheme is able to determine the optimum value of the reactive current injected by the auxiliary circuit in order to minimize extra conduction losses in the power MOSFETs, as well as the losses in the auxiliary circuit. In the proposed approach, the peak value of the reactive current is controlled by controlling the switching frequency to make sure that there is enough current to charge and discharge the snubber capacitors during the deadtime. In addition, some practical issues of this application (battery charger for an EV) are discussed in this paper. Experimental results for a 2-kW dc/dc converter are presented. The results show an improvement in efficiency and better performance of the converter. © 2011 IEEE. Source
Freescale Inc. | Date: 2013-08-30
A process integration is disclosed for fabricating non-volatile memory (NVM) cells having spacer control gates (
Freescale Inc. | Date: 2012-05-25
Embodiments include methods for forming an electrostatic discharge (ESD) protection device coupled across input-output (I/O) and common terminals of a core circuit, where the ESD protection device includes first and second merged bipolar transistors. A base of the first transistor serves as collector of the second transistor and the base of the second transistor serves as collector of the first transistor, the bases having, respectively, first and second widths. A first resistance is coupled between an emitter and base of the first transistor and a second resistance is coupled between an emitter and base of the second transistor. ESD trigger voltage Vt1 and holding voltage Vh can be independently optimized by choosing appropriate base widths and resistances. By increasing Vh to approximately equal Vt1, the ESD protection is more robust, especially for applications with narrow design windows, for example, with operating voltage close to the degradation voltage.
Freescale Inc. | Date: 2015-12-11
A method of fabricating a laterally diffused metal-oxide-semiconductor (LDMOS) transistor device having a bipolar transistor for electrostatic discharge (ESD) protection includes doping a substrate to form a body region of the LDMOS transistor device in the substrate, the body region having a first conductivity type, forming a doped isolating region of the LDMOS transistor device in the substrate, the doped isolating region having a second conductivity type and surrounding a device area of the LDMOS transistor device in which the body region is disposed, forming a base contact region of the bipolar transistor, the base contact region being disposed within the body region and having the first conductivity type, and doping the substrate to form an isolation contact region for the doped isolating region that defines a collector region of the bipolar transistor, to form source and drain regions of the LDMOS transistor device in the substrate, and to form an emitter region of the bipolar transistor within the body region.
Freescale Inc. | Date: 2013-03-15
A power source delivers power from a main power source using switching by a normally on transistor. A driver switches on and off the normally on transistor under a control signal by a controller during regular operation. A housekeeping power supply delivers auxiliary power to the driver. The driver switches off the normally on transistor during irregular operation. Irregular operation occurs at least when the control signal is absent or no auxiliary power is available or during transients such a power up or down. Bridge block pairs thereof can be arranged to form a half bridge power switch, an H bridge switch, a three phase bridge switch, a multi-phase switch, a buck converter, a buck-boost converter, or a boost converter.