Abstract: An example controller for a switched mode power supply includes a zero crossing detector, drive logic, and a logic gate. The zero-crossing detector generates a zero-crossing signal indicating a zero-crossing condition in the power supply. The drive logic generates a drive logic output signal in response to the zero-crossing signal and in response to a feedback signal, where the drive logic output signal is representative of an on-time of a switch to regulate an output of the power supply. The logic gate is coupled to receive a first signal representative of a current through the switch and a second signal representative of a zero-crossing time threshold. The logic gate is further coupled to extend the on-time of the switch until current through the switch reaches a zero-crossing current threshold or until the on-time of the switch reaches the zero-crossing time threshold.

Abstract: An example controller for a power converter includes a feedback sampling circuit, drive logic and a false sampling prevention circuit. The feedback sampling circuit is coupled to sample a feedback signal received from a terminal of the controller and to generate a sample signal representative of a value of the feedback signal. The drive logic is coupled to the feedback sampling circuit and coupled to control the power switch to regulate an output of the power converter in response to the sample signal. The false sampling prevention circuit is coupled to receive a sampling complete signal that indicates when the sampling of the feedback signal is complete. The false sampling prevention circuit is further coupled to the drive logic to extend the off time of the power switch until the sampling complete signal indicates that the sampling of the feedback signal by the feedback sampling circuit is complete.

Abstract: An example controller for a power converter includes a track and hold circuit, a sample and hold circuit, and drive logic. The track and hold circuit receives a signal that is representative of an output voltage of the power converter. The track and hold circuit includes a first capacitor that provides a first voltage that tracks the signal and then holds the first voltage. The sample and hold circuit then samples the first voltage that is held on the first capacitor. The sample and hold circuit includes a second capacitor that holds a second voltage representative of the first voltage after a fixed sample period. The second capacitor is larger than that of the first capacitor. The drive logic controlling the first switch to regulate the output of the power converter includes disabling the first switch during an on time of the first switch responsive to the second voltage.

Abstract: A method of operation for flyback power converter includes operating a controller of the flyback power converter in a regulation mode when a control signal is below a first threshold. The control signal is provided as an input to a terminal of the flyback power converter. When the control signal is below a second threshold and above the first threshold, the controller is operated in a limiting mode. The controller is operated in an external command mode when the control signal is below a third threshold and above the second threshold. Lastly, when the control signal is above the third threshold, the controller is operated in a protection mode.

Abstract: An example controller for a power converter includes a track and hold circuit, a sample and hold circuit, and drive logic. The track and hold circuit receives a signal from a terminal of the controller that is representative of an output voltage of the power converter. The track and hold circuit includes a first capacitor that provides a first voltage that tracks the signal and then holds the first voltage. The sample and hold circuit samples the first voltage when the first voltage is held on the first capacitor. The sample and hold circuit includes a second capacitor coupled to hold a second voltage representative of the first voltage after a sample period, where the second capacitor has a capacitance value larger than that of the first capacitor. The drive logic controls the first switch to regulate an output of the power converter in response to the second voltage.

Abstract: Methods and apparatuses for programming a parameter value in an IC (e.g., any power electronic device, such as a controller of a power converter) are disclosed. The parameter can be selected/programmed by selecting a clamp using an external optional (selectively inserted) diode coupled to a multi-function programming terminal. In particular, a controller IC for a power converter can be externally programmed via one or more multiple function terminals during startup of the converter to select between two or more options using the external programming terminal(s). Once programming is complete, internal programming circuitry may be decoupled from the programming terminal and during normal operation the programming terminal may then be used for another function, such as a bypass (BP) terminal to provide a supply voltage to the IC or other required functionalities.

Abstract: A controller for use in a power converter includes logic circuits to turn on and off a switch to regulate an output quantity. A first integrating capacitor is charged with a combination of a first current and a second current while the switch is turned on. The first current is proportional to a reset voltage and the second current is proportional to an input voltage. A reference generation circuit including a second integrating capacitor is charged with the first current during a previous switching cycle of the switch. The reference generation circuit generates a reference voltage in response to the second integrating capacitor. A comparator provides a stop signal to the logic circuits to turn off the switch in response to a comparison of a voltage across the first integrating capacitor with the reference voltage.

Abstract: An controller for use in a power supply includes a variable oscillator and a digital-to-analog converter (DAC). The variable oscillator generates a switching signal to control a first switch of the power supply to regulate an output current of the power supply. The variable oscillator sets a duration of an on-time of the switching signal to be inversely proportional to a magnitude of a first analog signal. The variable oscillator also sets a switching period of the switching signal to be inversely proportional to a magnitude of a second analog signal. The digital-to-analog converter (DAC) converts binary digits into the first and second analog signals, such that a sum of the magnitude of the first analog signal and the magnitude of the second analog signal is a fixed value.

Abstract: An example controller includes a measurement block and a drive block. The measurement block determines an amount of time that a dimmer circuit, that is coupled to an input of a power supply, disconnects an ac input voltage. The drive block generates a drive signal to control switching of a switch included in the power supply. The drive block operates a closed loop dimming control when the amount of time is less than or equal to a threshold and operates an open loop dimming control when the amount of time is greater than the threshold. The closed loop dimming control includes setting one or more operating conditions of the drive signal in response to a feedback signal that is representative of an output quantity of the power supply. The open loop dimming control includes holding the one or more operating conditions of the drive signal to a value.

Abstract: This relates to detecting unwanted couplings between a protected terminal and other terminals in an integrated controller of a power supply. Offset and clamp circuitry may apply a positive or negative offset voltage and clamp current to one or more terminals of the controller. In the event that a terminal having the offset voltage and clamp current is accidentally coupled to the protected terminal, the offset voltage and clamp current may be applied to the protected terminal. The protected terminal may be coupled to a fault detection circuitry operable to detect a fault signal at the protected terminal. The fault detection circuitry of the controller may cause the power supply to shut down in response to a detection of the fault signal at the protected terminal or may cause the power supply to shut down in response to a detection of a predefined threshold number of cycles in which the fault signal is detected.

Abstract: A method of operation for flyback power converter includes operating a controller of the flyback power converter in a regulation mode when a control signal is below a first threshold. The control signal is provided as an input to a terminal of the flyback power converter. When the control signal is below a second threshold and above the first threshold, the controller is operated in a limiting mode. The controller is operated in an external command mode when the control signal is below a third threshold and above the second threshold. Lastly, when the control signal is above the third threshold, the controller is operated in a protection mode.

Abstract: A controller for use in a power converter includes a comparator coupled to receive a signal representative of an output of the power converter. A counter is coupled to an output of the comparator to sample the output of the comparator a plurality of times within a period. A state machine is coupled to an output of the counter to control switching of the power converter according to one of a plurality of operating condition states in response to the output of the counter. The state machine is coupled to be updated at an end of the period.

Abstract: An example controller for a power supply includes a first circuit and a drive signal generator. The first circuit receives a first signal representative of a switch current flowing through a switch of the power supply and then generates a second signal in response the switch current not reaching a current threshold within an amount of time. The second signal indicates when a dimming circuit at an input of the power supply is utilized. The drive signal generator generates a drive signal to control switching of the switch in response to the second signal, where energy is transferred across an energy transfer element of the power supply in response to the switching of the switch.

Abstract: An example controller for a switched mode power supply includes a zero crossing detector, drive logic, and a logic gate. The zero-crossing detector generates a zero-crossing signal indicating a zero-crossing condition in the power supply. The drive logic generates a drive logic output signal in response to the zero-crossing signal and in response to a feedback signal, where the drive logic output signal is representative of an on-time of a switch to regulate an output of the power supply. The logic gate is coupled to receive a first signal representative of a current through the switch and a second signal representative of a zero-crossing time threshold. The logic gate is further coupled to extend the on-time of the switch until current through the switch reaches a zero-crossing current threshold or until the on-time of the switch reaches the zero-crossing time threshold.

Abstract: An controller for use in a power supply includes a variable oscillator and a digital-to-analog converter (DAC). The variable oscillator generates a switching signal having an on-time and a switching period to control a first switch to regulate an output of the power supply. The DAC provides the variable oscillator with a first analog signal and a second analog signal, where the on-time of the switching signal is responsive to the first analog signal and where the switching period is responsive to the second analog signal. The DAC includes a current source and a second switch that is configured to couple the current source to provide current to the first analog signal in response to a binary digit received by the DAC, and to couple the current source to provide current to the second analog signal in response to a complement of the binary digit.

Abstract: A switching power supply includes a switch and a controller for dimming control of the switching power supply. The controller includes a phase angle measurement block and a drive logic block. The phase angle measurement block is coupled to receive an input sense signal. The phase angle measurement block generates a phase angle signal representative of a phase angle of an input voltage of the power supply in response to the input sense signal. The drive logic block is coupled to control switching of the switch. The drive logic block controls the switch in a closed loop dimming control when the phase angle is less than or equal to a phase threshold and in a open loop dimming control when the phase angle is greater than the phase threshold.

Abstract: An example controller includes a comparator coupled to receive a feedback signal representative of an output of the power converter. A counter is coupled to receive an output of the comparator and a feedback sampling signal. The counter is coupled to sample the output of the comparator in response to the feedback sampling signal. A state machine is coupled to receive a feedback time period signal. The state machine is coupled to control switching of the power converter according to one of a plurality of operating conditions in response to the counter and the feedback time period signal. A period of the feedback time period signal is substantially greater than a period of the feedback sampling signal. The state machine is coupled to be updated in response to the feedback time period signal.

Abstract: An example controller for a switched mode power supply includes a drive signal generator and a zero-crossing detector. The drive signal generator is to be coupled to control switching of a switch included in the power supply to regulate an output of the power supply. The zero-crossing detector is coupled to the drive signal generator and coupled to receive a current sense signal representative of a switch current flowing through the switch. The zero-crossing detector generates a zero-crossing signal in response to comparing the current sense signal with a reference signal representative of a zero-crossing current threshold. The zero-crossing signal indicates when a zero-crossing condition of an ac line input voltage of the power supply exists.

Abstract: This relates to detecting unwanted couplings between a protected terminal and other terminals in an integrated controller of a power supply. Offset and clamp circuitry may apply a positive or negative offset voltage and clamp current to one or more terminals of the controller. In the event that a terminal having the offset voltage and clamp current is accidentally coupled to the protected terminal, the offset voltage and clamp current may be applied to the protected terminal. The protected terminal may be coupled to a fault detection circuitry operable to detect a fault signal at the protected terminal. The fault detection circuitry of the controller may cause the power supply to shut down in response to a detection of the fault signal at the protected terminal or may cause the power supply to shut down in response to a detection of a predefined threshold number of cycles in which the fault signal is detected.

Abstract: An example switched mode power supply includes a timer, a threshold adjust circuitry, a comparator, and a control circuitry. The timer times a duration between crossings of a phase-dimmed signal across a first threshold. The threshold adjust circuitry adjusts a second threshold representative of a desired output of the switched mode power supply, where the second threshold is adjusted responsive to the timed duration between crossings. The comparator compares a feedback signal with the second threshold and generates a comparison result. The control circuitry controls switching of a power switch responsive to the comparison result to regulate the output of the switched mode power supply.