Abstract:
An implantable blood pump includes motor control circuitry and power electronics circuitry integrated within the implantable pump body. The motor control circuitry and power electronics circuitry is configured to energize and control motor windings to rotate the pump rotor and impeller. Additional control circuitry and power electronics circuitry may be integrated within the pump housing to energize and control magnetic bearings of a magnetic levitation pump. A percutaneous cable coupled between the implantable blood pump and an extracorporeal monitor includes a reduced number of leads to provide power and control signals to the implantable blood pump. Wireless communication between the extracorporeal monitor and the integrated power electronics and control circuitry facilitates the use of a percutaneous cable with as few as two leads for providing power to the implantable pump.
Abstract:
A method of operating an isolated bi-directional dc/dc converter to provide voltage regulation at a no-load condition over a wide voltage range and also provide overshoot protection for the boost mode main switching transistors uses new boost mode drive waveforms. The new waveforms drive switches S2 and S4 to be turned off during boost mode and only S1 and S3 are switched to provide reverse energy flow at no-load. In boost mode, C1 and C2 provide overshoot protection caused by leakage inductance of the isolation transformer when boost mode drive transistors turn off during forward energy flow and provide stored energy for reverse energy flow during reverse energy flow periods used for voltage regulation in the boost mode. In buck mode, C1 and C2 provide soft switching for buck mode main switching transistors S2 and S4.
Abstract:
Systems and methods are provided for an on-demand boost converter for use in a vehicle. An automotive drive system comprises a boost converter having an input node, a first output node associated with a first boost leg, and a second output node associated with a second boost leg. A fuel cell is coupled to the input node of the boost converter and a battery is coupled to the first output node. An inverter module is coupled to the second output node, and a vehicle traction drive unit is coupled the inverter module. A first switch is coupled between the second output node and the first output node, wherein the battery provides energy to the second output node when the first switch is closed.
Abstract:
A current mode control circuit uses a current comparing module to control a switching signal according to one of a plurality of current feedback signals. The current mode circuit comprises a voltage control module that generates an output voltage according to an input voltage and the switching control signal, and that generates the plurality of current feedback signals. The current comparing module outputs a control current signal that is indicative of a greater one of the plurality of current feedback signals. A current mode control module receives the control current signal and generates the switching control signal according to the control current signal.
Abstract:
An autotransformer for use in low frequency, high power applications that uses a stack of printed wire boards constructed of a top, inner, and bottom layer including electrical trace windings circumventing the transformer core and formed in the inner layer for direct thermal contact with a heat sink interface providing a uniform and consistent heat path down to the heat sink plate. The autotransformer further includes a board to board connection employing solder cups to electrically connect between predetermined printed wire board traces. The printed wire board autotransformer also may use a non-planar interface for thermal interface with a non-planar heat sink plate surface.
Abstract:
A DC-to-DC converter and associated methods are provided for controlling the discharge of snubber capacitances during a light/no load buck mode of operation. An operating method for a DC-to-DC converter detects conditions corresponding to a light/no load buck mode of operation, and, in response to the detection of that mode, controls the states of a first switch, a second switch, a first switched diode element, a second switched diode element, a third switched diode element, and a fourth switched diode element to facilitate discharging of a first capacitance element and a second capacitance element through a secondary winding of a transformer.
Abstract:
A current mode control circuit uses a current comparing module to control a switching signal according to one of a plurality of current feedback signals. The current mode circuit comprises a voltage control module that generates an output voltage according to an input voltage and the switching control signal, and that generates the plurality of current feedback signals. The current comparing module outputs a control current signal that is indicative of a greater one of the plurality of current feedback signals. A current mode control module receives the control current signal and generates the switching control signal according to the control current signal.
Abstract:
A DC-DC converter comprises an input circuit that stores inductive energy that includes a first switch that releases the stored inductive energy. A transformer includes a primary winding that communicates with the input circuit and a secondary winding. An output circuit communicates with the secondary winding and that includes first and second output conductors and a first diode that communicates with one end of the secondary winding and the first output conductor. A second diode communicates with one end of the secondary winding and the second output conductor. A third diode communicates with an opposite end of the secondary winding and the first output conductor. A fourth diode communicates with an opposite end of the secondary winding and the second output conductor. A first capacitor is connected in parallel to the third diode. A second capacitor is connected in parallel to the fourth diode.
Abstract:
A full bridge DC to DC converter which provides zero voltage switching (ZVS) for one leg of the bridge and zero current switching (ZCS) for the other leg of the bridge is described. ZVS is achieved with parallel capacitors, while ZCS is achieved by using the reverse breakdown characteristics of the various diode and switching devices. This technique provides a significant reduction in the switching losses of the switching devices, which allows for higher power and frequency combinations.
Abstract:
Various methods and apparatuses that utilize a wireless time reference system are provided herein. One example method involves calibrating independent, spatially-located clocks of a geoposition system in order to geolocate an object having an associated object tag. The example method may include transmitting an RF pulse pair, receiving the pulse pair at multiple locations, utilizing respective frequencies of first and second spatially-located clocks to produce count values to effect measurement of an interarrival interval at each of multiple locations, determining a ratio of count values relative to said first and second spatially-located clocks, and utilizing said ratio to calibrate time indications of said clocks. Other related methods and apparatus are also provided.