Abstract: An example power converter includes an energy transfer element, a switch, and a control circuit. The control circuit includes a drive signal generator and an unregulated dormant mode control circuit. The unregulated dormant mode control circuit renders dormant the drive signal generator thereby ceasing the regulation of the output by the drive signal generator when the energy requirement of the one or more loads falls below a threshold for more than a first period of time. The drive signal generator is unresponsive to changes in the energy requirements of the one or more loads when dormant. The unregulated dormant mode control circuit powers up the drive signal generator after a second period of time has elapsed, such that the drive signal generator is again responsive to changes in the energy requirement of the one or more loads after the second period of time has elapsed.

Abstract: An example control circuit for use in a power converter includes an input voltage sensor, a current sensor, and a drive signal generator. The input voltage sensor generates a first signal representative of an input voltage (Vin) of the power converter. The current sensor generates a second signal representative of a switch current through a power switch of the power converter. The drive signal generator generates a drive signal to control switching of the power switch in response to the first and second signals. The drive signal generator sets a switching frequency of the drive signal based on a product K×Vin×t to control a maximum output power of the power converter, where K is a fixed number and t is a time it takes the second signal to change between two values of the switch current when the power switch is in an on state.

Abstract: A controller for use in a power converter includes a switching control and a sensor. The switching control generates a first signal to control switching of a power switch between a first state and a second state. The sensor receives a second signal from a single terminal of the controller during at least a portion of the time that the power switch is in the first state and during at least a portion of the time that the power switch is in the second state. The second signal is representative of a line input voltage during at least the portion of time that the power switch is in the first state and is representative of an output voltage during at least the portion of time that the power switch is in the second state. The sensor is coupled to be responsive to the first signal.

Abstract: A power converter controller includes a primary controller that is galvanically isolated from a secondary controller. The primary controller controls a state of a power switch during a first mode of operation according to a switching pattern defined by the primary controller. During a second mode of operation, the primary controller controls the state of the power switch in response to control signals received via a communication link. The secondary controller operates in a powered down state during the first mode of operation. The secondary controller initiates a transition operation with the primary controller that transitions the primary controller and the secondary controller from the first mode of operation to the second mode of operation. In the second mode of operation, the secondary controller transmit the control signals to the primary controller via the communication link.

Abstract: A voltage comparator includes an amplifier coupled to receive an input signal at an amplifier input and generate an output signal at an amplifier output in response to the input signal. The amplifier includes a current generation circuit coupled to generate a first current flowing through a first branch and a second current flowing through a second branch. A first transistor has a first terminal coupled to the amplifier input and a second terminal coupled to the first branch. A second transistor has a third terminal coupled to the second branch, a fourth terminal coupled to a reference voltage. A second control terminal of the second transistor is coupled to the first control terminal. An output circuit is coupled to the amplifier output to generate a comparator output signal in response to the output signal. The amplifier output is coupled to the second branch.

Abstract: A secondary control circuit includes a voltage regulator circuit to be coupled to an output of a power converter to provide a regulated power supply. One or more switched loads is coupled between a first terminal to be coupled to the output of the power converter and an output ground terminal. One or more comparator circuits is coupled to a second terminal coupled to receive an output sense signal. Each one of the one or more comparator circuits is coupled to receive a respective one of one or more reference signals. Each respective one of the one or more reference signals is a scaled representation of a first one of the one or more reference signals. Each one of the one or more switched loads is coupled to be switched in response to an output of a respective one of the one or more comparator circuits.

Abstract: A controller includes a control, a sensor, and a fault detector. The control is configured to control a switch to regulate an output of the power converter. The sensor receives a signal from a terminal of the controller that is representative of an input voltage during an ON state of the switch and is representative of an output voltage during an OFF state of the switch. The sensor is configured to sample the signal from the terminal during the ON state to generate a first sample signal and to sample the signal from the terminal during the OFF state to generate a second sample signal. The fault detector detects a fault condition in response to either the first or the second sample signals. The control inhibits the switching of the switch to reduce a power output level of the power converter in response to the fault condition.

Abstract: A controller includes a bypass terminal, a first power circuit, a second power circuit, and a charging control circuit. The bypass terminal is to be coupled to a bypass capacitor coupled to a secondary side of an isolated power converter. The first power circuit is coupled to the bypass terminal and a first terminal to be coupled to a first node of the secondary side. The first power circuit transfers charge from the first terminal to the bypass terminal for storage on the bypass capacitor. The second power circuit is coupled to the bypass terminal and a second terminal to be coupled to a second node of the secondary side. The second power circuit transfers charge from the second terminal to the bypass terminal for storage on the bypass capacitor. The charging control circuit controls which of the first and second power circuits transfers charge to the bypass terminal.

Abstract: A receive circuit for use in a power converter controller includes a first amplifier coupled to receive an input pulse. A second amplifier is coupled to a first output of the first amplifier. The first output is coupled to be responsive to the input pulse and to a second output of the second amplifier. An output circuit is coupled to generate an output signal in response to the second output.

Abstract: A controller includes a first controller terminal, a second controller terminal, a first p-channel metal-oxide-semiconductor field-effect transistor, and a second pMOS transistor. The first controller terminal is to be coupled to a bypass capacitor coupled to a secondary side of an isolated power converter. The second controller terminal to be coupled to an output node of the secondary side. The first pMOS transistor includes a first source terminal coupled to the second controller terminal, a first drain terminal, and a first body diode. The second pMOS transistor includes a second source terminal coupled to the first controller terminal, a second drain terminal coupled to the first drain terminal, and a second body diode. A cathode of the second body diode is coupled to the second source terminal. An anode of the second body diode is coupled to the second drain terminal.

Abstract: A secondary controller for use in a synchronous flyback converter includes a comparator, a drive circuit, and logic circuitry. The comparator is coupled to generate a compare signal in response to a comparison of a threshold to an input signal representative of a secondary winding voltage of the synchronous flyback converter. The drive circuit is coupled to generate a drive signal to control a first switch to be coupled to a primary side of the synchronous flyback converter. The drive signal is coupled to be generated by the drive circuit in response to a feedback signal representative of an output of the synchronous flyback converter. The logic circuitry is coupled to the drive circuit and coupled to the comparator. The logic circuitry is also coupled to generate a control signal to control a second switch in response to the drive signal and in response to the compare signal.

Abstract: A controller for use in a power converter includes a sensor coupled to receive a signal from a single terminal of the controller. The signal from the single terminal represents an output voltage of the power converter during at least a portion of an off time of a power switch and a line input voltage during a portion of an on time of the power switch. A switching control is to be coupled to switch the power switch to regulate the output of the power converter in response to the sensor. A power limiter is coupled to the sensor to output a power limit signal to the switching control in response to the line input voltage of the power converter. The switching control is further coupled to switch the power switch to regulate the output of the power converter in response to the power limit signal.

Abstract: An example controller includes a feedback circuit coupled to provide feedback information representative of an output of the power converter during at least a portion of an OFF time of a power switch. A sense input receives a sense signal that is representative of a reflected voltage representative of an input voltage of the power converter during at least a portion of an ON time of the power switch. A fault detector is to be coupled to detect a fault condition in response to the reflected voltage being below a fault threshold for a fault period of time. A control is coupled to the fault detector and the feedback circuit to control switching of the power switch to regulate the output of the power converter in response to the feedback information and inhibit the switching of the power switch in response to the fault detector detecting the fault condition.

Abstract: An apparatus includes an ON/OFF controller for regulating an output of a switched mode power supply by selectively enabling current conduction by a power switch within enabled switching cycles and disabling current conduction by the power switch within disabled switching cycles. The controller includes a logic block and a time-to-frequency converter. The logic block generates a drive signal that enables the current conduction by the power switch within respective enabled switching cycles and disables the current conduction by the power switch within respective disabled switching cycles. The time-to-frequency converter generates a variable-frequency clock signal that defines durations of the switching cycles, where the time-to-frequency converter increases a duration of a switching cycle in response to a decrease in duration of current conduction by the power switch in a previously enabled switching cycle.

Abstract: An example integrated control circuit includes a regulator, a first comparator, a second comparator, and a counter. The regulator is to charge, during a time period, a capacitor. The first comparator is to provide an output indicating when a voltage on the capacitor reaches a first threshold voltage. The second comparator is coupled to provide an output indicating when the voltage on the capacitor reaches a second threshold voltage. The counter is coupled to begin counting in response to the first threshold voltage being reached and is coupled to stop counting in response to the second threshold voltage being reached. The counter is coupled to provide an output representative of the capacitance value of the capacitor during the time period and the integrated control circuit receives a bias current at the terminal from the capacitor to provide power to operate the integrated control circuit after the time period has ended.

Abstract: A power converter controller includes a drive circuit coupled to control switching of a power switch to control a transfer of energy from an input of the power converter to an output of the power converter. A voltage sensor is coupled to the drive circuit to receive a feedback signal. The voltage sensor includes pulse sampler circuitry coupled to sample a first voltage representative of one of the peaks other than a first peak of ringing of the feedback signal in a first enabled switching cycle, sample a second voltage representative of the same peak of ringing of the feedback signal in a subsequent enabled switching cycle, and compare the sample of the first voltage with the sample of the second voltage and output a change signal based on the comparison. The drive circuit is further coupled to control switching of the power switch in response to the change signal.

Abstract: An on/off controller device includes a control circuit to generate a control signal to switch a power switch between an on state and an off state to transfer energy from a primary side to a secondary side of a switched mode power supply. A comparator is coupled to generate an enable signal that enables and disables the switching of the power switch by the control circuit. The comparator compares a feedback signal with a variable threshold and switches the enable signal between enabling and disabling the switching of the power switch. The variable threshold is modulated to increase a fundamental frequency of the switching of the power switch by the control circuit. The variable threshold is modulated with a fixed amplitude pulse that is combined with a second threshold to modulate the variable threshold between a first higher value and a second lower value.

Abstract: A power converter includes an input and an output. A regulation circuit is coupled between the power converter input and the power converter output. The regulation circuit is coupled to receive a feedback signal representative of the power converter output. The feedback signal has a first feedback state that represents a level at the power converter output that is above a threshold level and a second feedback state that represents a level at the power converter output that is below the threshold level. An oscillator is included in the regulation circuit that provides an oscillation signal that cycles between two states. The regulation circuit is coupled to be responsive to the oscillation signal and to a change between the first and second feedback states to enable or disable a flow of energy from the power converter input to the power converter output.

Abstract: A controller for regulating an output of a power supply includes a logic block and an oscillator. The logic block generates the drive signal to control switching of a power switch in response to a clock signal. The clock signal has a frequency that decreases responsive to a time period of the drive signal, where a decrease in the time period of the drive signal represents an increase in an input voltage of the power supply. The oscillator is coupled to generate the clock signal in response to a waveform having an amplitude swing. The oscillator alters the waveform in response to the time period of the drive signal.

Abstract: A switched-mode power supply includes an energy transfer element coupled between a primary side and a secondary side. A first main terminal of a switch is coupled to the energy transfer element and a second main terminal of the switch is coupled to an input of the primary side. A driver circuit is coupled to drive the switch to be open at a first one of a plurality of levels and closed at a second one of the plurality of levels. The driver circuit is coupled to drive the switch to be substantially independent of a voltage between the first and second main terminals at a third one of the plurality of levels. A current conducted between the first and second main terminals at the third one of the plurality of levels is sufficient to only partially discharge a capacitance that is coupled to the first main terminal.