Abstract: A flyback converter with forced primary regulation is disclosed. An example flyback converter includes a coupled inductor including a first winding, a second winding, and a third winding. The first winding is coupled to an input voltage and the second winding is coupled to an output of the power converter. A switched element is coupled to the second winding. A secondary control circuit is coupled to the switched element and the second winding. The secondary control circuit is coupled to switch the switched element in response to a difference between a desired output value and an actual output value to force a current in the third winding that is representative of the difference between the desired output value and the actual output value. A primary switch is coupled to the first winding. A primary control circuit is coupled to the primary switch and the third winding.

Abstract: A power supply control circuit is disclosed. In one aspect, a power supply control circuit includes a controller to be coupled to a switch to regulate an output of a power supply in response to a feedback signal and a parameter change signal. A parameter response circuit is coupled to generate the parameter change signal in response to a difference between a first value of a parameter measured before an event and a second value of the parameter measured after the event. The difference between the first value of the parameter and the second value of the parameter is representative of the relative efficiency of the power supply.

Abstract: An example controller includes a constant current control circuit and an integrator included in the constant current control circuit. The constant current control circuit is to be coupled to receive an input current sense signal, an input voltage sense signal, and an output voltage sense signal. The control circuit is adapted to regulate an output current of a power supply by generating a control signal to control switching of a switch. The integrator is coupled to integrate the input current sense signal during a switching period of the control signal to generate an integrated signal representative of a charge taken from an input voltage source of the power supply. The constant current control circuit is adapted to control the switching of the switch such that the integrated signal is proportional to a ratio of the output voltage sense signal to the input voltage sense signal.

Abstract: Techniques to compensate for parameter variations in a feedback circuit are disclosed. In one embodiment, a regulator circuit includes an energy source coupled to output a generated current in response to a control current. A feedback resistor is coupled to an output of the regulator circuit. The feedback resistor is coupled to conduct a feedback current responsive to the output of the regulator circuit. A current amplifier is coupled to the feedback resistor to generate the control current in response to the feedback current. A compensation network is coupled to the current amplifier to adjust the control current in response to an extrinsic parameter of the regulator circuit. The compensation network includes a transistor and first, second and third resistors. The first resistor is coupled between the feedback resistor and a collector of the transistor. The second resistor coupled between the collector and the base of the transistor.

Abstract: An example apparatus to regulate an output voltage of a power converter at light/no load conditions includes a driver circuit, a feedback circuit, and an adjustable voltage reference circuit. The driver circuit is coupled to output a drive signal to switch a power switch between an ON state and an OFF state to regulate an output of the power converter. The feedback circuit is coupled to the driver circuit and is further coupled to output an enable signal to switch the power switch to an ON state in response to an output voltage signal. The adjustable voltage reference circuit is coupled to adjust a voltage reference such that a bias winding voltage of the power converter is adjusted nonlinearly in response to a load that is to be coupled to the output of the power converter.

Abstract: Techniques are disclosed to detect a fault in the feedback circuit of a switching power supply while the power supply operates in a mode where the output is below its regulated value. The power supply delivers maximum power at a given switching frequency without a feedback signal while the output is below its regulated value. A fault protection circuit substantially reduces the average output power if there is no feedback signal for the duration of a fault time. When there is no feedback signal, the power supply increases the maximum output power by increasing the switching frequency before the end of the fault time to increase the output to a regulated value. The presence of a feedback signal when the output reaches a regulated value restores the original switching frequency and returns the output to its unregulated value. The absence of a feedback signal at the end of the fault time engages the fault protection circuit to substantially reduce the output power.

Abstract: Various techniques directed to providing temporary peak power from a switching regulator are disclosed. In one aspect, a switching regulator includes a switch that is to be coupled between a power supply input and an energy transfer element of the power supply. A controller is coupled to be responsive to a feedback signal to be received from an output of the power supply. The controller is coupled to switch the switch in response to the feedback signal to regulate the output of the power supply. An oscillator is coupled to provide an oscillating signal to the controller to determine a maximum switching frequency of the switch. The oscillating signal is coupled to oscillate at a first frequency under a first moderate load condition at the power supply output. The oscillating signal is coupled to oscillate at a second frequency under a second peak load condition at the power supply output.

Abstract: A flyback converter with forced primary regulation is disclosed. An example flyback converter includes a coupled inductor including a first winding, a second winding, and a third winding. The first winding is coupled to an input voltage and the second winding is coupled to an output of the power converter. A switched element is coupled to the second winding. A secondary control circuit is coupled to the switched element and the second winding. The secondary control circuit is coupled to switch the switched element in response to a difference between a desired output value and an actual output value to force a current in the third winding that is representative of the difference between the desired output value and the actual output value. A primary switch is coupled to the first winding. A primary control circuit is coupled to the primary switch and the third winding.

Abstract: A power supply control circuit is disclosed. In one aspect, a power supply control circuit includes a controller to be coupled to a switch to regulate an output of a power supply in response to a feedback signal and a parameter change signal. A parameter response circuit is coupled to generate the parameter change signal in response to a difference between a first value of a parameter measured before an event and a second value of the parameter measured after the event. The difference between the first value of the parameter and the second value of the parameter is representative of the relative efficiency of the power supply.

Abstract: A power supply control circuit is disclosed. In one aspect, a power supply control circuit includes a controller to be coupled to a switch to regulate an output of a power supply in response to a feedback signal and a parameter change signal. A parameter response circuit is coupled to generate the parameter change signal in response to a difference between a first value of a parameter measured before an event and a second value of the parameter measured after the event. The difference between the first value of the parameter and the second value of the parameter is representative of the relative efficiency of the power supply.

Abstract: Techniques are disclosed to detect a fault in the feedback circuit of a switching power supply while the power supply operates in a mode where the output is below its regulated value. The power supply delivers maximum power at a given switching frequency without a feedback signal while the output is below its regulated value. A fault protection circuit substantially reduces the average output power if there is no feedback signal for the duration of a fault time. When there is no feedback signal, the power supply increases the maximum output power by increasing the switching frequency before the end of the fault time to increase the output to a regulated value. The presence of a feedback signal when the output reaches a regulated value restores the original switching frequency and returns the output to its unregulated value. The absence of a feedback signal at the end of the fault time engages the fault protection circuit to substantially reduce the output power.

Abstract: Various techniques directed to providing temporary peak power from a switching regulator are disclosed. In one aspect, a switching regulator includes a switch that is to be coupled between a power supply input and an energy transfer element of the power supply. A controller is coupled to be responsive to a feedback signal to be received from an output of the power supply. The controller is coupled to switch the switch in response to the feedback signal to regulate the output of the power supply. An oscillator is coupled to provide an oscillating signal to the controller to determine a maximum switching frequency of the switch. The oscillating signal is coupled to oscillate at a first frequency under a first moderate load condition at the power supply output. The oscillating signal is coupled to oscillate at a second frequency under a second peak load condition at the power supply output.

Abstract: A power supply control circuit is disclosed. In one aspect, a power supply control circuit includes a controller to be coupled to a switch to regulate an output of a power supply in response to a feedback signal and a parameter change signal. A parameter response circuit is coupled to generate the parameter change signal in response to a difference between a first value of a parameter measured before an event and a second value of the parameter measured after the event. The difference between the first value of the parameter and the second value of the parameter is representative of the relative efficiency of the power supply.

Abstract: A time-differential analog comparator is disclosed. An example apparatus according to aspects of the present invention includes a source of a variable frequency signal having a frequency responsive to an analog input. A counting circuit is coupled to count cycles of the variable frequency signal. The counting circuit is coupled to count in a first direction for a first time interval and is coupled to count in a second direction opposite to the first direction for a second time interval that occurs after an end of the first time interval. An evaluation circuit is coupled to the counting circuit. The evaluation circuit is responsive to the count of the cycles of the variable frequency signal after an end of the second time interval.

Abstract: A reduced cost energy transfer element for power converter circuits. In one embodiment, an energy transfer element according to an embodiment of the present invention includes a magnetic element having an external surface with at least a first winding and a second winding wound around the external surface of the magnetic element without a bobbin. As such, energy to be received from a power converter circuit input is to be transferred from the first winding to the second winding through a magnetic coupling provided by the magnetic element to a power converter circuit output.

Abstract: Techniques are disclosed to detect a fault in the feedback circuit of a switching power supply while the power supply operates in a mode where the output is below its regulated value. The power supply delivers maximum power at a given switching frequency without a feedback signal while the output is below its regulated value. A fault protection circuit substantially reduces the average output power if there is no feedback signal for the duration of a fault time. When there is no feedback signal, the power supply increases the maximum output power by increasing the switching frequency before the end of the fault time to increase the output to a regulated value. The presence of a feedback signal when the output reaches a regulated value restores the original switching frequency and returns the output to its unregulated value. The absence of a feedback signal at the end of the fault time engages the fault protection circuit to substantially reduce the output power.

Abstract: Various techniques directed to providing temporary peak power from a switching regulator are disclosed. In one aspect, a switching regulator includes a switch that is to be coupled between a power supply input and an energy transfer element of the power supply. A controller is coupled to be responsive to a feedback signal to be received from an output of the power supply. The controller is coupled to switch the switch in response to the feedback signal to regulate the output of the power supply. An oscillator is coupled to provide an oscillating signal to the controller to determine a maximum switching frequency of the switch. The oscillating signal is coupled to oscillate at a first frequency under a first moderate load condition at the power supply output. The oscillating signal is coupled to oscillate at a second frequency under a second peak load condition at the power supply output.

Abstract: A reduced cost energy transfer element for power converter circuits. In one embodiment, an energy transfer element according to an embodiment of the present invention includes a magnetic element having an external surface with at least a first winding and a second winding wound around the external surface of the magnetic element without a bobbin. As such, energy to be received from a power converter circuit input is to be transferred from the first winding to the second winding through a magnetic coupling provided by the magnetic element to a power converter circuit output.

Abstract: Various techniques directed to providing temporary peak power from a switching regulator are disclosed. In one aspect, a switching regulator includes a switch that is to be coupled between a power supply input and an energy transfer element of the power supply. A controller is coupled to be responsive to a feedback signal to be received from an output of the power supply. The controller is coupled to switch the switch in response to the feedback signal to regulate the output of the power supply. An oscillator is coupled to provide an oscillating signal to the controller to determine a maximum switching frequency of the switch. The oscillating signal is coupled to oscillate at a first frequency under a first moderate load condition at the power supply output. The oscillating signal is coupled to oscillate at a second frequency under a second peak load condition at the power supply output.

Abstract: A reduced cost energy transfer element for power converter circuits. In one embodiment, an energy transfer element according to an embodiment of the present invention includes a magnetic element having an external surface with at least a first winding and a second winding wound around the external surface of the magnetic element without a bobbin. As such, energy to be received from a power converter circuit input is to be transferred from the first winding to the second winding through a magnetic coupling provided by the magnetic element to a power converter circuit output.