Abstract: In a PFC (power factor correction) control unit for controlling a PFC converter, a transconductance amplifier is coupled to receive a feedback signal representative of an output voltage of the PFC converter. The transconductance amplifier is coupled to generate an output error signal in response to the feedback signal. A PWM (pulse width modulated) converter is coupled to receive the output error signal, the PWM converter is coupled to generate a PWM signal in response to the output error signal. A chopper is coupled to receive the PWM signal. The chopper is coupled to switch a current representative of an input current of the PFC converter in response to the PWM signal. A filter is coupled to receive the switched current representative of the input current of the PFC converter. The filter is coupled to generate a PFC converter control signal in response to the filtered switched current representative of the input current of the PFC converter.

Abstract: In a PFC (power factor correction) control unit for controlling a PFC converter, a transconductance amplifier is coupled to receive a feedback signal representative of an output voltage of the PFC converter. The transconductance amplifier is coupled to generate an output error signal in response to the feedback signal. A PWM (pulse width modulated) converter is coupled to receive the output error signal, the PWM converter is coupled to generate a PWM signal in response to the output error signal. A chopper is coupled to receive the PWM signal. The chopper is coupled to switch a current representative of an input current of the PFC converter in response to the PWM signal. A filter is coupled to receive the switched current representative of the input current of the PFC converter. The filter is coupled to generate a PFC converter control signal in response to the filtered switched current representative of the input current of the PFC converter.

Abstract: A power supply includes a PFC (power factor correction) converter that has an input and an output. The PFC converter input is coupled to an input of the power supply. The power supply also includes a resonant mode converter that has an input and an output. The resonant mode converter input is coupled to the PFC converter output and the resonant mode output is coupled to an output of the power supply. A control unit is also included in the power supply and is coupled to receive a feedback signal that is representative of the output of the power supply. The control unit is coupled to provide control signals coupled to control switches of the resonant mode converter at a controlled switching frequency to control the output of the power supply. The control unit is further coupled to provide a PFC control signal coupled to control a switch of the PFC converter at a switching frequency that is harmonically related to the controlled switching frequency.

Abstract: In a PFC (Power Factor Correction) converter control unit, a PWM (pulse width modulated) signal is produced by comparing a PFC converter output voltage error signal, produced by a transconductance amplifier, with a ramp signal, which may be from a control unit of a resonant mode converter in cascade with the PFC converter. Level shifting is used to match the amplitude ranges of the compared signals. A current, representing an input current of the PFC converter and produced by a current mirror, is switched by the PWM signal to a parallel resistance and capacitance to produce a smoothed voltage constituting a control signal for the PFC converter.

Abstract: A control unit controls cascaded PFC and LLC converters, the LLC converter having an input coupled to an output, of the PFC converter and providing an output voltage that decreases with increasing switching frequency. The control unit produces a sawtooth waveform with a linear ramp for controlling the LLC converter switching frequency, and hence its output voltage, in dependence upon a feedback signal. It also produces for the PFC converter a PWM signal with a frequency that is the same as or an integer fraction of the LLC converter switching frequency, by comparing two thresholds with the linear ramp in respective different cycles of the sawtooth waveform to turn on and off a switch of the PFC converter during these different cycles. Logic circuits prevent PFC converter switch transitions from occurring simultaneously with switching transitions of the LLC converter.

Abstract: A power supply trim control signal is produced by integrating differences between monitored and target values of the output voltage of a power supply. Register storage requirements are reduced by producing the target value from a nominal voltage value and one of a plurality of margin offsets selected in accordance with control data. The control data also selects between open and closed loop trim control. Stability is enhanced by changing the target value slowly in response to any change in the control data.

Abstract: A power supply trim control signal is produced by integrating differences between monitored and target values of the output voltage of a power supply. Register storage requirements are reduced by producing the target value from a nominal voltage value and one of a plurality of margin offsets selected in accordance with control data. The control data also selects between open and closed loop trim control. Stability is enhanced by changing the target value slowly in response to any change in the control data.

Abstract: A control unit controls cascaded PFC and LLC converters, the LLC converter having an input coupled to an output, of the PFC converter and providing an output voltage that decreases with increasing switching frequency. The control unit produces a sawtooth waveform with a linear ramp for controlling the LLC converter switching frequency, and hence its output voltage, in dependence upon a feedback signal. It also produces for the PFC converter a PWM signal with a frequency that is the same as or an integer fraction of the LLC converter switching frequency, by comparing two thresholds with the linear ramp in respective different cycles of the sawtooth waveform to turn on and off a switch of the PFC converter during these different cycles. Logic circuits prevent PFC converter switch transitions from occurring simultaneously with switching transitions of the LLC converter.

Abstract: A power supply trim control signal is produced by integrating differences between monitored and target values of the output voltage of a power supply. Register storage requirements are reduced by producing the target value from a nominal voltage value and one of a plurality of margin offsets selected in accordance with control data. The control data also selects between open and closed loop trim control. Stability is enhanced by changing the target value slowly in response to any change in the control data.

Abstract: In a PFC (Power Factor Correction) converter control unit, a PWM (pulse width modulated) signal is produced by comparing a PFC converter output voltage error signal, produced by a transconductance amplifier, with a ramp signal, which may be from a control unit of a resonant mode converter in cascade with the PFC converter. Level shifting is used to match the amplitude ranges of the compared signals. A current, representing an input current of the PFC converter and produced by a current mirror, is switched by the PWM signal to a parallel resistance and capacitance to produce a smoothed voltage constituting a control signal for the PFC converter.

Abstract: Power supplies, supplied with an input voltage to produce output voltages, are controlled in a desired sequence, and their output voltages are monitored, by respective state machines of two or more control units which are coupled in cascade by a bidirectional signal path on which commands and acknowledgements are coupled serially in frames. Within each control unit, each state machine communicates with all of the other state machines, so that the power supplies controlled by a single control unit can include divergent and convergent as well as linear sequence paths. The sequence is linear between adjacent control units, with logical combinations of received and locally-produced commands and acknowledgements. An input state machine in the first control unit in the cascade monitors the input voltage to initiate a power-up sequence.

Abstract: A power supply controller has two control units for coupling to primary and secondary sides of controlled power supplies, the units being coupled via a transformer which couples signals between the units, a power supply voltage for the secondary-side unit being derived from signals coupled from the primary-side unit. Initially signals are coupled from the primary unit with an increasing duty cycle to charge a secondary-side power supply capacitor. Subsequently signals are coupled in signal frames in alternating directions between the units, each signal frame from each unit indicating whether or not signal frames are correctly received from the other control unit. The signal frames also provide for downloading information for the control units, and other status signals and commands and acknowledgements.

Abstract: Power supplies, supplied with an input voltage to produce output voltages, are controlled in a desired sequence, and their output voltages are monitored, by respective state machines of two or more control units which are coupled in cascade by a bidirectional signal path on which commands and acknowledgements are coupled serially in frames. Within each control unit, each state machine communicates with all of the other state machines, so that the power supplies controlled by a single control unit can include divergent and convergent as well as linear sequence paths. The sequence is linear between adjacent control units, with logical combinations of received and locally-produced commands and acknowledgements. An input state machine in the first control unit in the cascade monitors the input voltage to initiate a power-up sequence.

Abstract: A power supply controller has two control units for coupling to primary and secondary sides of controlled power supplies, the units being coupled via a transformer which couples signals between the units, a power supply voltage for the secondary-side unit being derived from signals coupled from the primary-side unit. Initially signals are coupled from the primary unit with an increasing duty cycle to charge a secondary-side power supply capacitor. Subsequently signals are coupled in signal frames in alternating directions between the units, each signal frame from each unit indicating whether or not signal frames are correctly received from the other control unit. The signal frames also provide for downloading information for the control units, and other status signals and commands and acknowledgements.