Abstract: A power converter in one aspect limits the magnetic flux in a transformer. A control circuit included in the power converter includes a pulse width modulator, a logic circuit and a saturation prevention circuit. The saturation prevention circuit asserts a first signal when a first integral value of the input voltage reaches a first threshold value and asserts a second signal after a delay time that begins when a difference between the first integral value and a second integral value of a reset voltage of the transformer falls to a second threshold value. The logic circuit turns off the switch when the first signal is asserted, and allows the switch to turn on and off in accordance with the pulse width modulator when the second signal is asserted.

Abstract: A power supply includes a first power converter having a first transformer coupled to an input of the power supply and to a first output of the power supply. A clamp reset circuit is coupled to the first transformer. The clamp reset circuit includes a capacitor coupled to the first power converter and a Zener diode coupled to the capacitor. A second power converter is coupled to the clamp reset circuit. The second power converter includes a second transformer coupled to the clamp circuit and to a second output of the power supply. The capacitor is coupled to store energy received from the first power converter and the second power converter. The Zener diode is coupled to prevent the energy received from the first power converter and the second power converter from exceeding a threshold. The Zener diode limits voltage on the capacitor.

Abstract: A power supply includes a first power converter, a second power converter, and a clamp reset circuit. The clamp reset circuit is electrically coupled to other components within the first power converter and the second power converter. A clamp standby connection can be provided to electrically couple the clamp reset circuit to components comprising the second power converter. The clamp reset circuit is coupled to reduce magnetizing energy of a transformer of the first power converter and limit voltage in a component of the second power converter. The clamp reset circuit may include a Zener diode and a resistor that are adapted to reduce magnetizing energy of the first power converter and voltage through the second power converter. The clamp reset circuit normally includes a capacitor that is adapted to store energy from the first power converter and the second power converter.

Abstract: An integrated circuit includes a threshold detection circuit that is coupled to measure a signal from a first resistive external circuit coupled between a fourth external terminal of the integrated circuit and a first external terminal of the integrated circuit during a duration of an initialization period after the fourth external terminal has been charged to a supply threshold value. A regulator circuit is coupled to charge the fourth external terminal to the supply threshold value during the initialization period of the integrated circuit. A selection circuit is coupled to the threshold detection circuit to select a parameter/mode of the integrated circuit in response to the signal measured from the first resistive external circuit during the duration of the initialization period after the fourth external terminal has been charged to the supply threshold value.

Abstract: A switching circuit for use in a power supply includes a first active switch coupled to a first terminal of a primary winding of a transformer. A second active switch is coupled to a second terminal of the primary winding of the transformer. An output capacitance of the first active switch is greater than an output capacitance of the second active switch. A first passive switch is coupled to the second active switch and to the second terminal of the primary winding. A second passive switch is coupled to the first active switch and to the first terminal of the primary winding. A reverse recovery time of the first passive switch is greater than a reverse recovery time of the second passive switch. A recovery circuit is coupled to receive a current from the first passive switch.

Abstract: A power converter in one aspect limits the magnetic flux in a transformer. A control circuit included in the power converter includes a pulse width modulator, a logic circuit and a saturation prevention circuit. The saturation prevention circuit asserts a first signal when a first integral value of the input voltage reaches a first threshold value and asserts a second signal after a delay time that begins when a difference between the first integral value and a second integral value of a reset voltage of the transformer falls to a second threshold value. The logic circuit turns off the switch when the first signal is asserted, and allows the switch to turn on and off in accordance with the pulse width modulator when the second signal is asserted.

Abstract: A switching circuit for use in a power converter in one aspect includes a first and second active switch and a first and second passive switch. The first active switch can be coupled to a first terminal of a primary winding of a transformer. The second active switch can be coupled to a second terminal of the primary winding of the transformer. The output capacitance of the first active switch is greater than the output capacitance of the second active switch. The first passive switch can be coupled to the second active switch and to the second terminal of the primary winding. The second passive switch can be coupled to the first active switch and to the first terminal of the primary winding. The reverse recovery time of the first passive switch is greater than the reverse recovery time of the second passive switch.

Abstract: An integrated circuit includes a threshold detection circuit that is coupled to measure a signal from a first resistive external circuit coupled between a fourth external terminal of the integrated circuit and a first external terminal of the integrated circuit during a duration of an initialization period after the fourth external terminal has been charged to a supply threshold value. A regulator circuit is coupled to charge the fourth external terminal to the supply threshold value during the initialization period of the integrated circuit. A selection circuit is coupled to the threshold detection circuit to select a parameter/mode of the integrated circuit in response to the signal measured from the first resistive external circuit during the duration of the initialization period after the fourth external terminal has been charged to the supply threshold value.

Abstract: A power converter in one aspect limits the magnetic flux in a transformer. A control circuit included in the power converter includes a pulse width modulator, logic circuits and saturation prevention circuits. The saturation prevention circuits assert a first signal when a first integral value of the input voltage reaches a first threshold value and assert a second signal after a delay time that begins when a difference between the first integral value and a second integral value of a reset voltage of the transformer falls to a second threshold value. The logic circuits turn off the switch when the first signal is asserted, and allow the switch to turn on and off in accordance with the pulse width modulator when the second signal is asserted.

Abstract: Techniques are disclosed to select functional parameters and/or operating modes of a circuit based on a measurement during an initialization period. In one aspect an integrated circuit includes a threshold detection circuit coupled to measure during an initialization period of the integrated circuit a signal from a first external circuit comprising one or more components coupled to a first external terminal of the integrated circuit. A selection circuit is coupled to the threshold detection circuit to select a parameter/mode of the integrated circuit in response to the signal from the first external circuit during the initialization period of the integrated circuit. The first external terminal is further coupled to one or more additional external circuits, each of which comprising one or more components.

Abstract: An example power supply includes a first power converter, a second power converter, and a shared clamp reset circuit. The first power converter is adapted to convert an input to a first output and includes a first transformer having a first primary winding. The second power converter is also adapted to convert the input to a second output and includes a second transformer having a second primary winding. The second primary winding of the second transformer is not the first primary winding of the first transformer. The shared clamp reset circuit is coupled to the first primary winding of the first transformer and is coupled to the second primary winding of the second transformer to manage leakage inductance energy within the first transformer and within the second transformer.

Abstract: A circuit with an isolation interface and a remote on/off function is disclosed. The circuit includes a controller included in a primary side of the circuit. The controller is coupled to receive a primary side feedback signal and the controller is configured to enter a shutdown mode when the primary side feedback signal exceeds a feedback signal threshold. The circuit also includes an isolation interface coupled to galvanically isolate the primary side from a secondary side of the circuit. The isolation interface translates a secondary side feedback signal from the secondary side into the primary side feedback signal on the primary side. The isolation interface is configured to adjust the primary side feedback signal to exceed the feedback signal threshold in response to an on/off signal.

Abstract: A power converter in one aspect limits the magnetic flux in a transformer. A control circuit included in the power converter includes a pulse width modulator, logic circuits and saturation prevention circuits. The saturation prevention circuits assert a first signal when a first integral value of the input voltage reaches a first threshold value and assert a second signal after a delay time that begins when a difference between the first integral value and a second integral value of a reset voltage of the transformer falls to a second threshold value. The logic circuits turn off the switch when the first signal is asserted, and allow the switch to turn on and off in accordance with the pulse width modulator when the second signal is asserted.

Abstract: A power supply includes a first power converter, a second power converter, and a clamp reset circuit. The clamp reset circuit is electrically coupled to other components within the first power converter and the second power converter. A clamp standby connection can be provided to electrically couple the clamp reset circuit to components comprising the second power converter. The clamp reset circuit is coupled to reduce magnetizing energy of a transformer of the first power converter and limit voltage in a component of the second power converter. The clamp reset circuit may include a Zener diode and a resistor that are adapted to reduce magnetizing energy of the first power converter and manage leakage inductance energy through the second power converter. The clamp reset circuit normally includes a capacitor that is adapted to store energy from the first power converter and the second power converter.

Abstract: A control circuit for use in a power converter in one aspect limits the magnetic flux in a transformer. Controlled current sources produce a first current that is proportional to an input voltage of the power converter and a second current that is proportional to a reset voltage of the transformer. An integrating capacitor is charged with the first current and discharged with the second current, where a voltage on the capacitor is representative of the magnetic flux in the transformer. A logic circuit is adapted to turn off the switch when the voltage on the integrating capacitor is greater than or equal to a first threshold voltage, and to allow the switch to turn on and off in accordance with a pulse width modulation signal after a delay time that begins when the integrating capacitor discharges to a second threshold voltage.

Abstract: A control circuit for use in a power converter in one aspect limits the magnetic flux in a transformer. Controlled current sources produce a first current that is proportional to an input voltage of the power converter and a second current that is proportional to a reset voltage of the transformer. An integrating capacitor is charged with the first current and discharged with the second current, where a voltage on the capacitor is representative of the magnetic flux in the transformer. A logic circuit is adapted to turn off the switch when the voltage on the integrating capacitor is greater than or equal to a first threshold voltage, and to allow the switch to turn on and off in accordance with a pulse width modulation signal after a delay time that begins when the integrating capacitor discharges to a second threshold voltage.

Abstract: A control circuit for use in a power converter in one aspect limits the magnetic flux in a transformer of a switching power converter. A first controlled current source has a first current that is substantially directly proportional to an input voltage to be applied to a winding of the transformer. A second controlled current source has a second current that is substantially directly proportional to a reset voltage to be applied to the winding of the transformer. A first switch is adapted to charge an integrating capacitor with the first current while the input voltage is applied to the winding of the transformer. A second switch is adapted to discharge the integrating capacitor with the second current when the reset voltage is applied to the winding of the transformer. A third switch is adapted to remove and to prevent application of the input voltage to the winding of the transformer.

Abstract: A power supply includes a first power converter, a second power converter, and a clamp reset circuit. The clamp reset circuit is electrically coupled to other components within the first power converter and the second power converter. A clamp standby connection can be provided to electrically couple the clamp reset circuit to components comprising the second power converter. The clamp reset circuit is coupled to reduce magnetizing energy of a transformer of the first power converter and limit voltage in a component of the second power converter. The clamp reset circuit may include a Zener diode and a resistor that are adapted to reduce magnetizing energy of the first power converter and manage leakage inductance energy through the second power converter. The clamp reset circuit normally includes a capacitor that is adapted to store energy from the first power converter and the second power converter.

Abstract: An in-rush current limiting circuit is disclosed. An apparatus according to aspects of the present invention includes a power switch having a first, second and third terminals. A capacitor having a first terminal and a second terminal is also included. The second terminal of the capacitor is coupled to the first terminal of a current source. The second terminal of the current source is coupled to a second input terminal of the in-rush current limit circuit. A power switch is also included. The first terminal of the power switch is coupled to the anode of a diode. The cathode of the diode is connected to the first terminal of the current source. The second terminal of the power switch is coupled to a second input terminal of the in-rush current limit circuit. The third terminal of the power switch is coupled to be responsive to a voltage across the current source circuit in response to a rate of change of voltage between first and second terminals of the power switch.

Abstract: Techniques are disclosed to regulate a power supply with a compensation signal generation circuit. One example regulated power supply includes a sense circuit coupled to sense an output voltage of the regulated power supply. The regulated power supply also includes a switching power converter circuit, which includes a switch coupled to be switched in response to a control signal received from the sense circuit to regulate the output voltage of the regulated power supply. The regulated power supply also includes a compensation signal generation circuit coupled to receive a switching signal representative of a switching of the switch in the switching power converter circuit. The compensation signal generation circuit is to generate a compensation signal responsive to the switching signal. The compensation signal is to be received by the sense circuit to modify the control signal.