Abstract: A multi-phase DC-DC converter includes a substrate having opposing first and second sides, a plurality of power stage packages attached to the first side of the substrate, each power stage package including active semiconductor components operable to provide an output phase of the multi-phase DC-DC converter, and a coupled inductor attached to the first side of the substrate and at least partly covering two or more of the power stage packages. The coupled inductor includes separate windings wound on the same core. Each winding of the coupled inductor electrically connects an output of one of the power stage packages at least partly covered by the coupled inductor to a metal trace on the substrate such that the outputs of the power stage packages at least partly covered by the coupled inductor are electrically connected to the same metal trace on the substrate.

Abstract: A switching voltage converter using an isolated topology includes a transformer for coupling power from an input source to an output load. The transformer must be protected to prevent saturation of its core due to excessive magnetic flux density as the transformer transfers power from its primary side to its secondary side. The magnetic flux is estimated using a voltage measured on the primary or secondary side of the transformer, wherein the secondary-side voltage may be a rectified voltage. If the estimated magnetic flux is detected as approaching a saturation level of the transformer core, any power being input to the transformer is curtailed. This may be accomplished by modifying pulse-width modulated (PWM) waveforms controlling power switches that control the input power transferred to the transformer. Using these techniques, transformer saturation may be avoided without requiring a significantly oversized transformer within the voltage converter.

Abstract: A voltage regulator includes a power stage configured to produce an output voltage from an input voltage at an input voltage terminal, a shunt resistor connected in series between the input voltage terminal and the power stage, a first level shifting resistor connected in series between a first terminal of the shunt resistor and a first sense pin of the controller, and a second level shifting resistor connected in series between a second terminal of the shunt resistor and a second sense pin of the controller. The input current of the regulator is sensed as a function of the voltage across the shunt resistor, as shifted down by the level shifting resistors and measured across the sense pins. The input voltage of the regulator is sensed as a function of the current flowing through either one of the level shifting resistors, as measured at one of the sense pins.

Abstract: An isolated power converter includes primary side switch devices coupled to secondary side rectifying devices by a transformer and a controller. Responsive to a transient load condition, the controller switches the primary side switch devices at an initial switching period having a positive half cycle and a negative half cycle to transfer energy across the transformer during the positive half cycle and the negative half cycle. The positive half cycle and the negative half cycle of the initial switching period have the same initial duration. The controller is further operable to symmetrically reduce the duration of the positive half cycle and the negative half cycle for at least one subsequent switching period during the transient load condition.

Abstract: A resonant or semi-resonant DC/DC converter makes use of one or more synchronous rectification (SR) switches for rectifying an output current that is provided to a load of the converter. The SR switches are ideally turned off when zero current is flowing through them. To achieve such zero-current switching, the current through each of the SR switches is monitored and compared against a turn-off threshold. The turn-off threshold for a particular SR switch is determined from the slope of a waveform of the current together with a transition delay for turning off the SR switch. This transition delay typically includes a delay through a driver circuit for the SR switch together with a latency through the SR switch itself. Once it is detected that the current for an SR switch has dropped to or below the turn-off threshold, a signal is provided to the SR switch turning it off.

Abstract: An estimate of voltage regulator input power is provide by estimating output power of the voltage regulator based on output voltage and output current of the voltage regulator, estimating power loss of the voltage regulator and estimating input power of the voltage regulator based on the estimated output power and the estimated power loss.

Abstract: A method of controlling an isolated DC-DC converter includes switching the primary side switching devices of the converter at a fixed first switching period and variable duty cycle during non-transient load conditions so as to transfer energy across the transformer of the converter during first energy transfer intervals separated by energy circulation intervals, such that the ratio of each first energy transfer interval to the first switching period is less than unity. The method also includes switching the primary side switching devices at a second switching period different than the first switching period during a transient load condition so as to transfer energy across the transformer during second energy transfer intervals of a duration determined so as to avoid saturation of the transformer core, and such that any energy circulation interval separating the second energy transfer intervals is shorter than the energy circulation intervals separating the first energy transfer intervals.

Abstract: Techniques are provided for controlling power switches that couple an input power source to a transformer within a voltage converter, in order to control the power transfer through the transformer and to a load of the voltage converter. Different techniques are provided for different operational modes. In an initial steady-state interval, the switches are switched using a fixed first switching period and variable duty cycle. Upon detecting a load transient, e.g., a sudden increase in the load power requirements, a ramp-up interval is entered during which the switches are switched using a second switching period and a second duty cycle, in order to increase the output current of the converter at a maximum rate. Upon detecting that a current within the voltage converter has reached a maximum allowed level, a current-limited interval is entered during which the switches are switched using a third switching period and a third duty cycle.

Abstract: A rectification and regulation circuit for a wireless power receiver includes a coil for magnetically coupling to a primary coil of a power transmitter, a full-wave rectifier circuit separate from the power transmitter and a control unit separate from the power transmitter. The full-wave rectifier has a first pair of controllable rectifiers including a first transistor connected to a first terminal of the coil and a second transistor connected to a second terminal of the coil. The control unit is operable to control switching of the transistors of the full-wave rectifier so that the full-wave rectifier (a) generates a rectified output for charging a battery of the wireless power receiver by rectifying current through the coil or voltage across the coil, and (b) regulates the rectified output.

Abstract: A DC/DC voltage converter includes a first stage operable to convert a first DC voltage rail to a second DC voltage rail different than the first DC voltage rail and a second stage operable to convert the second DC voltage rail to a third DC voltage rail lower than the second DC voltage rail and deliver current to a load at the third DC voltage rail, the amount of current delivered to the load corresponding to an operating set point of the second stage. The second stage is operable to change its operating set point responsive to a command received from the load, such that the amount of current delivered to the load is reduced. The first stage is operable to change its operating set point responsive to a command issued by the load, such that the amount of current delivered to the second stage is reduced.

Abstract: A switching voltage converter using an isolated topology includes a transformer for coupling power from an input source to an output load. The transformer must be protected to prevent saturation of its core due to excessive magnetic flux density as the transformer transfers power from its primary side to its secondary side. The magnetic flux is estimated using a voltage measured on the primary or secondary side of the transformer, wherein the secondary-side voltage may be a rectified voltage. If the estimated magnetic flux is detected as approaching a saturation level of the transformer core, any power being input to the transformer is curtailed. This may be accomplished by modifying pulse-width modulated (PWM) waveforms controlling power switches that control the input power transferred to the transformer. Using these techniques, transformer saturation may be avoided without requiring a significantly oversized transformer within the voltage converter.

Abstract: A method of managing system resources managing resource utilization for a system board that includes a plurality of processors, memory associated with each of the processors, a plurality of voltage regulators configured to regulate voltages applied to the processors and memories, and a board manager configured to manage resources of the system board includes communicating operating condition information from the board manager to controllers of the voltage regulators independent of the processors also communicating with the controllers, the operating condition information received by each controller indicating a computing load for the processor regulated by the voltage regulator controlled by that controller.

Abstract: A power converter includes an input power source, a synchronous rectifier and a controller. The synchronous rectifier includes a plurality of actively controlled switches coupled in parallel and configured to rectify current delivered from the input power source to a load. The controller is operable to issue a first control signal for driving a first one of the actively controlled switches and issue a second control signal for driving a second one of the actively controlled switches. The first control signal is a different control signal than the second control signal so that the first actively controlled switch is controllable separately from the second actively controlled switch. The first actively controlled switch has a higher current-carrying capacity than the second actively controlled switch.

Abstract: Circuits that provide an auxiliary power supply on the secondary side of an isolated switched-mode power converter are described. Such an auxiliary supply may be used to provide power to a secondary side controller or to other circuitry in the secondary side of the power converter. During at least a start-up phase of the power converter, the secondary side auxiliary power supply is supplied power by use of a self-starting primary side driver that operates autonomously until the secondary side controller is fully operational. Circuits and methods for such a self-starting primary side driver are provided. The techniques disclosed provide for a secondary side auxiliary power supply that uses minimal additional circuitry.

Abstract: A time delay through a voltage converter, including a transformer therein, must be known or estimated in order to optimally control the voltage converter. For example, power switches that control the input power to the voltage converter must use this time delay in order to, e.g., achieve zero-voltage switching (ZVS) with minimal dead-time. The time delays are typically considered as constants, and the power switch control is optimized for a limited operational range that corresponds to such constant time delays. Herein, variable time delays are determined based upon varying load conditions of the voltage converter. By more accurately determining the time delay for a given load condition and basing the voltage converter control on such accurate (load-dependent) time delays, the voltage converter may be more optimally controlled and achieve higher efficiency.

Abstract: A switching voltage converter using an isolated topology includes a transformer for coupling power from an input source to an output load. The transformer must be protected to prevent saturation of its core due to excessive magnetic flux density as the transformer transfers power from its primary side to its secondary side. The magnetic flux is estimated using a voltage measured on the primary or secondary side of the transformer, wherein the secondary-side voltage may be a rectified voltage. If the estimated magnetic flux is detected as approaching a saturation level of the transformer core, any power being input to the transformer is curtailed. This may be accomplished by modifying pulse-width modulated (PWM) waveforms controlling power switches that control the input power transferred to the transformer. Using these techniques, transformer saturation may be avoided without requiring a significantly oversized transformer within the voltage converter.

Abstract: Circuits that provide an auxiliary power supply on the secondary side of an isolated switched-mode power converter are described. Such an auxiliary supply may be used to provide power to a secondary side controller or to other circuitry in the secondary side of the power converter. During at least a start-up phase of the power converter, the secondary side auxiliary power supply is supplied power by use of a self-starting primary side driver that operates autonomously until the secondary side controller is fully operational. Circuits and methods for such a self-starting primary side driver are provided. The techniques disclosed provide for a secondary side auxiliary power supply that uses minimal additional circuitry.

Abstract: A secondary-side rectification and regulation circuit includes a secondary-side transformer winding, a full-wave rectifier circuit and a control unit. The full-wave rectifier has a first pair of controllable rectifiers including a first transistor connected to a first terminal of the secondary-side transformer winding and a second transistor connected to a second terminal of the secondary-side transformer winding. The control unit is operable to control switching of the transistors of the full-wave rectifier so that the full-wave rectifier (a) generates a rectified output for supplying a load by rectifying current through the secondary-side transformer winding or voltage across the secondary-side transformer winding and (b) regulates the rectified output.

Abstract: A rectification and regulation circuit for a wireless power receiver includes a coil for magnetically coupling to a primary coil of a power transmitter, a full-wave rectifier circuit separate from the power transmitter and a control unit separate from the power transmitter. The full-wave rectifier has a first pair of controllable rectifiers including a first transistor connected to a first terminal of the coil and a second transistor connected to a second terminal of the coil. The control unit is operable to control switching of the transistors of the full-wave rectifier so that the full-wave rectifier (a) generates a rectified output for charging a battery f the wireless power receiver by rectifying current through the coil or voltage across the coil, and (b) regulates the rectified output.

Abstract: A power converter includes an input power source, a synchronous rectifier and a controller. The synchronous rectifier includes a plurality of actively controlled switches coupled in parallel and configured to rectify current delivered from the input power source to a load. The controller is operable to issue a first control signal for driving a first one of the actively controlled switches and issue a second control signal for driving a second one of the actively controlled switches. The first control signal is a different control signal than the second control signal so that the first actively controlled switch is controllable separately from the second actively controlled switch. The first actively controlled switch has a higher current-carrying capacity than the second actively controlled switch.