Abstract: An inductor-inductor-capacitor (EEC) power converter with high efficiency for Electric Vehicle (EV) on-board low voltage DC-DC chargers (LDC) is disclosed. The converter includes a switching bridge with a plurality of bridge switches and configured to generate an output from a direct current input voltage. An EEC tank circuit is coupled to the switching bridge and includes a resonant inductor and a resonant capacitor and a parallel inductor connected between the resonant inductor and the resonant capacitor. The tank circuit is configured to output a resonant sinusoidal current from the output of the switching bridge. At least one transformer has at least one primary winding in parallel with the parallel inductor of the inductor-inductor-capacitor tank circuit and at least one secondary winding. At least one rectifier is coupled to the at least one secondary winding and is configured to output a rectified alternating current.

Abstract: A power converter includes an integrated multi-layer cooling structure. The power converter includes a plurality of printed circuit boards (PCBs) stacked together in a generally vertical arrangement. A liquid cooling mechanism is attached to a lower-most PCB, and high loss circuitry components are attached to an opposite side of the lower-most PCB. Low loss circuitry components are attached to further PCBs. Magnetic components may be attached to the further PCBs. The high loss components are actively cooled by the liquid cooling mechanism and the low loss components and magnetic components are passively cooled. The liquid cooling mechanism may be a cold plate heatsink. The power converter may include intermediate PCBs disposed between the upper-most PCB and the lower-most PCB, with low loss circuitry components attached to the intermediate PCBs.

Abstract: Controllers and methods for controlling a resonant power converter output voltage include operating the power converter according to a control period comprising an on cycle operation mode for a duration T_on that produces a first voltage Vo1 and an off cycle operation mode for a duration T_off that produces a second voltage Vo2. Vo1 is produced using a first switching frequency for a first selected number of switching cycles corresponding to the on time T_on. The converter output voltage or the converter input and output voltages may be sensed and used to determine the switching frequency during the on cycle operation mode and the duration of the off cycle operation mode. The final output voltage of the power converter is regulated to a selected value based on a ration of (T_on):(T_on+T_off). The controllers and methods may be used with power converters in power delivery devices to accept wide input voltage ranges compatible with devices such as cell phones, tablet computers, and notebook computers.

Abstract: Packaging methods and structures for lateral high voltage gallium nitride (GaN) devices achieve electrical isolation while also maintaining thermal dissipation. The electrical isolation reduces or eliminates vertical leakage current, improving high voltage performance. The packages may use or be compatible standards such as JEDEC, which reduces packaging cost and facilitates implementation of the packaged devices in conventional circuit design approaches.

Abstract: In an AC-DC converter having a primary side control circuit, auxiliary power for the control circuit is derived from the converter secondary side through an isolated DC-DC converter. The circuits and methods solve the problem of supplying primary side auxiliary power during light load or no load operation of the AC-DC power converter. Since the output voltage of the AC-DC converter is normally regulated at a fixed level, the auxiliary voltage that is generated by the isolated DC converter is regulated. In some cases the isolated DC-DC converter may not need to be regulated, which simplifies the design and reduces overall cost.

Abstract: A converter includes input voltage terminals, a series circuit connected to the input voltage terminals and including first and second switches connected in series, a transformer including a primary winding and a secondary winding, a resonant tank connected to the series circuit and including the primary winding, an auxiliary switch connected to the series circuit and the resonant tank, output voltage terminals connected to the secondary winding, and a controller that, based on a single control loop and a single control parameter, controls the auxiliary switch with pulse-width modulation and controls the first and second switches with pulse-frequency modulation.

Abstract: A multi-stage, multi-level DC-DC step-down converter includes a first stage and a second stage having two identical cells connected in parallel. The first stage includes an input capacitor, four switches, and one flying capacitor. The two cells of the second stage each include four switches and one flying capacitor, and an output filter. The cells of the second stage are driven at half the switching frequency of the input stage, and provides a step-down ratio of 4:1. A third stage having four cells may be added to achieve a step-down ratio of 8:1, a fourth stage having eight cells may be added to achieve a step-down ration of 16:1, etc., each additional stage including a doubling of the number of cells connected in parallel, with all cells being substantially identical, and each stage operating at a further reduced fraction of the switching frequency. Embodiments are particularly suitable for applications such as a 48V intermediate bus architecture for servers and datacenters.

Abstract: A series circuit includes a capacitor connected in series with a power converter output terminals. The power converter provides an auxiliary voltage and a controller controls the power converter auxiliary voltage according to a selected function, such that the series circuit behaves as a capacitor, an inductor, or an impedance, based on the selected function. The controller may sense a voltage across the capacitor and use the sensed voltage to control the power converter auxiliary voltage according to the selected function. The series circuit may be connected in parallel with output terminals of an AC-DC converter, wherein the series circuit operates according to a selected mode to produce the auxiliary voltage, and the auxiliary voltage substantially cancels a low frequency AC voltage ripple across the capacitor, such that a substantially pure DC output voltage is delivered to the load.

Abstract: Resonant converters may be operated according to selected working modes to achieve voltage doubler or non-voltage doubler functions. Embodiments may be based on two-phase resonant converters. Embodiments may implement primary side switching, secondary side switching, or both, to achieve the selected working modes and voltage doubler and non-voltage doubler function. Embodiments are suitable for applications requiring wide input and output voltage ranges, such as low-voltage charging circuits for personal electronic devices, and high voltage charging circuits for electric vehicles.

Abstract: An LLC converter includes a transformer that includes a primary winding and a secondary winding, a resonant stage that includes the primary winding, a switching stage that includes switches and that is connected to an input voltage and the resonant stage, a rectifying stage that is connected to the secondary winding and that provides an output voltage, and a controller that senses the output voltage and that controls switching of the switches based on proportional-integral control of the output voltage to reduce errors in the output voltage with respect to a DC voltage and based on quasi-resonant control of the output voltage to reduce errors in the output voltage with respect to a range of voltages with a frequency bandwidth.

Abstract: A packaged GaN semiconductor device with improved heat dissipation is provided. A GaN device is packaged on a printed circuit board (PCB) with a vertical side of the device, and optionally the back side of the device, in thermal contact with the PCB. The packaging is compatible with surface mount technologies such as land grid array (LGA), ball grid array (BGA), and other formats. Thermal contact between the PCB and a vertical side of the device, and optionally the back side of the device, is made through solder. The solder used for the thermal contact may also connect a source terminal of the device, which also improves electrical stability of the device. The packaging is particularly suitable for GaN HEMT devices.

Abstract: A start-up circuit for a power converter includes a charging circuit that uses a DC bus voltage of the power converter to generate a charging current to charge an energy storage device to a selected voltage and an auxiliary power output circuit including a transformer primary side auxiliary winding. A control circuit controls one or more switches of the start-up circuit and one or more switches of the power converter primary side. The charging current provides power to the control circuit until the auxiliary power is established. The control circuit disables the start-up circuit when the auxiliary power output is established. The start-up circuit has very low standby power consumption and compact size, and is particularly suitable for power converter applications such as power adapters for portable electronic devices.

Abstract: In an AC-DC converter having a primary side control circuit, auxiliary power for the control circuit is derived from the converter secondary side through an isolated DC-DC converter. The circuits and methods solve the problem of supplying primary side auxiliary power during light load or no load operation of the AC-DC power converter. Since the output voltage of the AC-DC converter is normally regulated at a fixed level, the auxiliary voltage that is generated by the isolated DC converter is regulated. In some cases the isolated DC-DC converter may not need to be regulated, which simplifies the design and reduces overall cost.

Abstract: Use of gallium nitride (GaN) semiconductor material for power devices is challenging due to low yield caused by high defect density on the wafer. Device layout on the wafer, chip probing, and device packaging increase the yield of large area power devices. Device dies containing a plurality of lower-power sub-devices are used to achieve high power ratings, by connecting only functional sub-devices together in the package, while being tolerant of defective sub-devices by selectively excluding the defective sub-devices. The packages and methods are particularly relevant to GaN power switching devices such as high electron mobility transistors (GaN HEMT).

Abstract: A gate driver circuit for a gallium nitride (GaN) power transistor includes a RS-flipflop that receives a first pulse train at an S input terminal and a second pulse train at an R input terminal, and produces an output pulse train, and an amplifier that amplifies the output pulse train and produces a gate driver signal for the GaN power transistor. The RS-flipflop and the amplifier may be implemented together on a GaN monolithic integrated circuit, optionally together with the GaN power transistor. The GaN power transistor may be a high-side switch of a half-bridge circuit. The RS-flipflop may be implemented with enhancement mode and depletion mode GaN high electron mobility transistors (HEMTs). Embodiments avoid drawbacks of prior hybrid (e.g., silicon-GaN) approaches, such as parasitic inductances from bonding wires and on-board metal traces, especially at high operating frequencies, as well as reduce implementation cost and improve performance.

Abstract: Resonant converters with wide voltage gain ranges are achieved by controlling at least one of the primary side resonant circuit and the secondary side rectifier circuit. A switch is included in at least one of the primary or secondary sides, and control of the switch according to a selected mode determines an output voltage of the resonant converter. Embodiments accommodate wide input and output voltage ranges, and are suitable for use in AC-DC power adapters for portable devices with different voltage requirements, such as cell phones, tablets, and notebook computers, as well as in DC-DC converter applications including electric vehicle power systems.

Abstract: Packaging methods and structures for lateral high voltage gallium nitride (GaN) devices achieve electrical isolation while also maintaining thermal dissipation. The electrical isolation reduces or eliminates vertical leakage current, improving high voltage performance. The packages may use or be compatible standards such as JEDEC, which reduces packaging cost and facilitates implementation of the packaged devices in conventional circuit design approaches.

Abstract: Three-phase single-stage AC-DC converters achieve power factor correction with low phase voltage switch stress. Direct input current sensing is performed to calculate the average input current of the AC-DC converter and implement power factor correction. Embodiments feature high power factor, single stage power conversion, and soft-switching of all switches, resulting in high conversion efficiency in a cost-effective single-stage three-phase structure. The converters have low output voltage ripple without a double line frequency component, which allows non-electrolytic capacitor implementation. The converters are particularly useful in high-power applications such as electric vehicle charging.

Abstract: A converter includes input voltage terminals, a series circuit connected to the input voltage terminals and including first and second switches connected in series, a transformer including a primary winding and a secondary winding, a resonant tank connected to the series circuit and including the primary winding, an auxiliary switch connected to the series circuit and the resonant tank, output voltage terminals connected to the secondary winding, and a controller that, based on a single control loop and a single control parameter, controls the auxiliary switch with pulse-width modulation and controls the first and second switches with pulse-frequency modulation.

Abstract: Voltage stabilizing and voltage regulating circuits implemented in GaN HEMT technology provide stable output voltages suitable for use in applications such as GaN power transistor gate drivers and low voltage auxiliary power supplies for GaN integrated circuits. Gate driver and voltage regulator modules include at least one GaN D-mode HEMT (DHEMT) and at least two GaN E-mode HEMTs (EHEMTs) connected together in series, so that the at least one DHEMT operates as a variable resistor and the at least two EHEMTs operate as a Zener diode that limits the output voltage. The gate driver and voltage regulator modules may be implemented as a GaN integrated circuits, and may be monolithically integrated together with other components such as amplifiers and power HEMTs on a single die to provide a GaN HEMT power module IC.