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 multiphase voltage regulator includes a plurality of phases and a controller. Each phase is configured to output a phase current to a load through an inductor in response to a control signal input to the phase. The controller is operable to: generate the control signals input to the phases; set a switching frequency of the control signals to a first value; and change the switching frequency from the first value to a second value different than the first value if the load current changes repetitively at a frequency that is within a predetermined range of the first value of the switching frequency. A corresponding method of operating the multiphase voltage regulator is also provided.

Abstract: A multiphase voltage regulator includes a plurality of phases and a controller. Each phase is configured to output a phase current to a load through an inductor in response to a control signal input to the phase. The controller is operable to: generate the control signals input to the phases; set a switching frequency of the control signals to a first value; and change the switching frequency from the first value to a second value different than the first value if the load current changes repetitively at a frequency that is within a predetermined range of the first value of the switching frequency. A corresponding method of operating the multiphase voltage regulator is also provided.

Abstract: A voltage converter includes a power stage coupled to a power source, a passive circuit coupling the power stage to an output capacitor, a synchronous rectification (SR) switch operable to couple the passive circuit to ground when the SR switch is conducting, a linear controller and an adaptive voltage positioning (AVP) circuit. The linear controller is operable to control switching of the SR switch and switch devices included in the power stage, to regulate an output voltage of the voltage converter based on a reference voltage. The AVP circuit operable to generate an offset voltage applied to the reference voltage based on a first signal representing output current of the voltage converter, and to subtract a second signal from the first signal. The second signal approximates a surge current applied to the output capacitor via the passive circuit for charging the output capacitor during transitions in the reference voltage.

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 switched-capacitor converter includes a rectifier at the output, a plurality of legs coupled between the input and the rectifier, and a controller. Each leg of the switched-capacitor converter includes a capacitor, and a switch device is connected to each leg. A first group of the legs is coupled to a first branch of the rectifier, and a second group of the legs is coupled to a second branch of the rectifier. The controller alternates switching of the first and second groups of legs after startup, to transfer energy from the input to the output during a first part of each switching cycle via the first group of legs and to ground during a second part of each switching cycle via the second group of legs. The controller or a current limited source provides for pre-charging of at least one of the capacitors during startup.

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 switched-capacitor converter includes a plurality of legs coupled between the input and a rectifier at the output. Each leg includes a capacitor. A first group of legs is coupled to a first branch of the rectifier, and a second group is coupled to a second branch of the rectifier. A switch device is connected to each leg. The controller alternates switching of the switch devices connected to the first and second groups of legs to transfer energy from input to output. The switching is modified based on zero-crossing information which indicates when current through each switch device crosses or nearly crosses zero, so that each switch device connected to the same group of legs is turned off when current through that switch device crosses or nearly crosses zero and remains off until all switch devices connected to that group have been turned off for a predetermined amount of time.

Abstract: A voltage converter includes a power stage coupled to a power source, a passive circuit coupling the power stage to an output capacitor, a synchronous rectification (SR) switch operable to couple the passive circuit to ground when the SR switch is conducting, a linear controller and an adaptive voltage positioning (AVP) circuit. The linear controller is operable to control switching of the SR switch and switch devices included in the power stage, to regulate an output voltage of the voltage converter based on a reference voltage. The AVP circuit operable to generate an offset voltage applied to the reference voltage based on a first signal representing output current of the voltage converter, and to subtract a second signal from the first signal. The second signal approximates a surge current applied to the output capacitor via the passive circuit for charging the output capacitor during transitions in the reference voltage.

Abstract: Controller circuitry controls power supply circuitry to produce an output voltage. During operation of the power supply circuitry to produce the output voltage, the controller circuitry calculates a magnitude of capacitance of output capacitor circuitry in the power supply. According to one configuration, the controller circuitry utilizes a calculated magnitude of capacitance as a basis to adjust settings of the power supply circuitry.

Abstract: A semi-resonant voltage converter has a synchronous rectification (SR) switch through which a half-cycle sinusoidal-like current is conducted when turned on. An embodiment of a method of controlling operation of the semi-resonant voltage converter includes switching the SR switch and other switches of the semi-resonant voltage converter via a linear controller so as to supply output power to a load, the semi-resonant voltage converter having a DC gain that increases when load current increases, and scaling downward an output of the linear controller used to control the switching of the SR switch responsive to the load current exceeding a first threshold, so as to at least partly counteract an increase in the DC gain of the semi-resonant voltage converter. Other control adaptation methods are also described.

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: 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 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: Each phase of a multi-phase voltage converter includes a power stage, passive circuit, and synchronous rectification (SR) switch. Each passive circuit couples its associated 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. A 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 first power transistor of a DC-DC converter is connected between a voltage supply node and a common node, a second power transistor is connected between a reference node and the common node, and an inductor is connected between the common node and the output node of the DC-DC converter. A controller switches the first transistor off and the second transistor off during a step-down event at the load if current in the inductor exceeds a positive threshold value.

Abstract: A phase current estimator for a switching power converter includes analog circuitry for generating a phase current estimate error by comparing a phase current of the switching power converter to an analog representation of an estimate of the phase current, the phase current having a sawtooth or triangular waveform. The phase current estimator further includes digital circuitry for revising the phase current estimate based on the phase current estimate error and a plurality of parameters associated with operation of the switching power converter, so that the phase current estimate tracks the sawtooth or triangular waveform of the phase current.

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: A semi-resonant voltage converter has a synchronous rectification (SR) switch through which a half-cycle sinusoidal-like current is conducted when turned on. An embodiment of a method of controlling operation of the semi-resonant voltage converter includes switching the SR switch and other switches of the semi-resonant voltage converter via a linear controller so as to supply output power to a load, the semi-resonant voltage converter having a DC gain that increases when load current increases, and scaling downward an output of the linear controller used to control the switching of the SR switch responsive to the load current exceeding a first threshold, so as to at least partly counteract an increase in the DC gain of the semi-resonant voltage converter. Other control adaptation methods are also described.

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.