Abstract: A voltage regulation system for providing power to a load is provided. The voltage regulation system includes a voltage regulator operable to: set an operating voltage of the load at a first voltage level which corresponds to a first voltage requirement of the load; receive a second voltage requirement of the load which is different than the first voltage requirement; produce a voltage ramp signal which transitions from the first voltage level to a second voltage level which corresponds to the second voltage requirement at a defined ramp rate; and ramp the operating voltage from the first voltage level to the second voltage level based on the voltage ramp signal and at the same ramp rate as the voltage ramp signal, but with a lag between the voltage ramp signal and the ramp in the operating voltage.

Abstract: A multi-phase power supply circuit includes at least a first phase and a second phase (such as semi-resonant DC-DC power converter circuits), each of which output current to power a load. The first phase includes a first inductor device through which first current is delivered to the load. The second phase includes a second inductor device through which second current is delivered to the load. A current monitor circuit of the multi-phase power supply circuit is operable to monitor current through the second inductor device. Control circuitry of the multi-phase power supply circuit is operable to adjust timing of activating a control switch in the second phase to an ON state based on the monitored current. Timing of the phases is adjusted to achieve a common switching and zero current switching amongst the phases.

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: Each phase of a multi-phase voltage converter includes a power stage, passive circuit, synchronous rectification (SR) switch, and control circuit. Each passive circuit couples its power stage to an output node of the voltage converter, and is switchably coupled to ground by the SR switch. The current through the SR switch has a half-cycle sinusoidal shape with a resonant frequency determined by the reactance of the passive circuit. The control circuit generates signals to control switches within the power stage and the SR switches. The control circuit measures current through the SR switch of each phase, and determines which of the phases has SR switch current which returns to zero the quickest. This phase is identified as a master, and the other phases of the voltage converter are aligned to this master phase such that none of the SR switches is turned off when negative current is flowing through it.

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 state machine for a multi-phase voltage converter controls cycle-by-cycle switching of the phases by: entering a first state in which a control signal for the high-side switch is activate and control signals for the low-side and SR (synchronous rectification) switches are deactivate; entering a second state in which the control signals for all switches are deactivate; entering a third state in which the control signal for the high-side switch is deactivate and the control signals for the low-side and SR switches are activate; entering a fourth state in which the control signals for the high-side and low-side switches are deactivate and the control signal for the SR switch is activate and then entering a fifth state in which the control signals for all switches are deactivate, or entering the fifth state without entering the fourth state; and entering the first state at the beginning of the next switching cycle.

Abstract: Each phase of a multi-phase voltage converter includes a power stage, passive circuit, synchronous rectification (SR) switch, and control circuit. Each passive circuit couples its power stage to an output node of the voltage converter, and is switchably coupled to ground by the SR switch. The current through the SR switch has a half-cycle sinusoidal shape with a resonant frequency determined by the reactance of the passive circuit. The control circuit generates signals to control switches within the power stage and the SR switches. The control circuit measures current through the SR switch of each phase, and adjusts the duty cycles of the control signals for the phases so that the SR switches are switched off when zero or almost zero current is flowing through them.

Abstract: A resonant or semi-resonant voltage converter includes a synchronous rectification (SR) switch through which a current having a half-cycle sinusoidal-like shape is conducted when the SR switch is active. The current through the SR switch is modelled, and estimates of the SR switch current are generated by a digital estimator based on the model. The SR switch current estimates are updated at a fairly fast rate, as may be needed by a controller of the voltage converter. Analog converters are run at a slower rate, and generate error signals that are fed back into the digital estimator in order to improve future SR switch current estimates. Because the analog converters run at a fairly slow rate, power usage is minimal. However, the SR switch current estimates are updated at a rate that is fast enough to provide adequate control for the voltage converter.

Abstract: A voltage regulation system for providing power to a load is provided. The voltage regulation system includes a voltage regulator operable to set an operating voltage of the load at a first voltage level which corresponds to a first voltage requirement of the load, receive a second voltage requirement of the load which is different than the first voltage requirement and produce a voltage ramp from the first voltage level to the second voltage level. The voltage regulator is further operable to transition the operating voltage from the first voltage level to the second voltage level at a same ramp rate as the voltage ramp and with a lag between the voltage ramp and the transition in the operating voltage.

Abstract: A resonant or semi-resonant voltage converter includes a synchronous rectification (SR) switch through which a current having a half-cycle sinusoidal-like shape is conducted when the SR switch is active. The current through the SR switch is estimated, so that a zero-crossing condition may be detected and used for turning off the SR switch near the optimal point at which zero current is flowing through the SR switch. The current through the SR switch may be estimated based upon a measurement of the current flowing through the SR switch, a measurement of the current flowing out from the secondary side of a transformer in the voltage converter, or a measurement corresponding to the current flowing into the primary side of the transformer.

Abstract: A resonant or semi-resonant voltage converter includes a synchronous rectification (SR) switch through which a current having a half-cycle sinusoidal-like shape is conducted when the SR switch is active. The current through the SR switch is modelled, and estimates of the SR switch current are generated by a digital estimator based on the model. The SR switch current estimates are updated at a fairly fast rate, as may be needed by a controller of the voltage converter. Analog converters are run at a slower rate, and generate error signals that are fed back into the digital estimator in order to improve future SR switch current estimates. Because the analog converters run at a fairly slow rate, power usage is minimal. However, the SR switch current estimates are updated at a rate that is fast enough to provide adequate control for the voltage converter.

Abstract: Each phase of a multi-phase voltage converter includes a power stage, passive circuit, synchronous rectification (SR) switch, and control circuit. Each passive circuit couples its power stage to an output node of the voltage converter, and is switchably coupled to ground by the SR switch. The current through the SR switch has a half-cycle sinusoidal shape with a resonant frequency determined by the reactance of the passive circuit. The control circuit generates signals to control switches within the power stage and the SR switches. The control circuit measures current through the SR switch of each phase, and determines which of the phases has SR switch current which returns to zero the quickest. This phase is identified as a master, and the other phases of the voltage converter are aligned to this master phase such that none of the SR switches is turned off when negative current is flowing through it.

Abstract: Each phase of a multi-phase voltage converter includes a power stage, passive circuit, synchronous rectification (SR) switch, and control circuit. Each passive circuit couples its power stage to an output node of the voltage converter, and is switchably coupled to ground by the SR switch. The current through the SR switch has a half-cycle sinusoidal shape with a resonant frequency determined by the reactance of the passive circuit. The control circuit generates signals to control switches within the power stage and the SR switches. The control circuit measures current through the SR switch of each phase, and adjusts the duty cycles of the control signals for the phases so that the SR switches are switched off when zero or almost zero current is flowing through them.

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 converter includes a power stage, a passive circuit, a synchronous rectification (SR) switch component, and a control circuit. The passive circuit couples the power stage to an output node of the voltage converter, and is switchably coupled to ground by the SR switch component. The SR switch component includes a plurality of SR switches, which are independently controllable. The control circuit determines which of the SR switches are to be activated/enabled, and only uses those SR switches in its variable switching of the voltage converter. The determination of which SR switches are to be activated/enabled is based upon an estimate of the output current for the voltage converter. By using more SR switches when the voltage converter is fully loaded, and fewer SR switches when it is lightly loaded, the power loss of the SR switch component is minimized and the voltage converter is more power efficient.

Abstract: Each phase of a multi-phase voltage converter includes a power stage, passive circuit, synchronous rectification (SR) switch, and control circuit. Each passive circuit couples its power stage to an output node of the voltage converter, and is switchably coupled to ground by the SR switch. The current through the SR switch has a half-cycle sinusoidal shape with a resonant frequency determined by the reactance of the passive circuit. The control circuit generates signals to control switches within the power stage and the SR switches. The control circuit measures current through the SR switch of each phase, and adjusts the duty cycles of the control signals for the phases so that the SR switches are switched off when zero or almost zero current is flowing through them.

Abstract: A state machine for a multi-phase voltage converter controls cycle-by-cycle switching of the phases by: entering a first state in which a control signal for the high-side switch is activate and control signals for the low-side and SR (synchronous rectification) switches are deactivate; entering a second state in which the control signals for all switches are deactivate; entering a third state in which the control signal for the high-side switch is deactivate and the control signals for the low-side and SR switches are activate; entering a fourth state in which the control signals for the high-side and low-side switches are deactivate and the control signal for the SR switch is activate and then entering a fifth state in which the control signals for all switches are deactivate, or entering the fifth state without entering the fourth state; and entering the first state at the beginning of the next switching cycle.

Abstract: A voltage converter includes a variable switching frequency power stage, a passive circuit and a control circuit. The power stage includes a high-side switch and a first low-side switch coupled to the high-side switch at a switching node of the power stage. The passive circuit couples the switching node to an output node of the voltage converter. The control circuit is operable to control cycle-by-cycle switching of the power stage and sample current at a point between the switching node and the output node, the sampled current having a half cycle sinusodial-like shape each switching cycle. For the present switching cycle, the control circuit is operable to calculate an average of the sampled current for the immediately preceding switching cycle and estimate the average sampled current for the present switching cycle based on the average sampled current calculated for the immediately preceding switching cycle.

Abstract: Control loop coefficients for a digital voltage regulator controller are determined by determining PID (proportional-integral-derivative) coefficients that satisfy gain and phase margin targets for a digital voltage regulator controller, as a function of a plurality of system parameters for the digital voltage regulator controller, and re-determining one or more of the PID coefficients to flatten an output impedance response of the digital voltage regulator controller for frequencies below a bandwidth of the digital voltage regulator controller.