Abstract: A multi-mode converter using iterative average current mode pulse width modulation (PWM) control is provided. The converter may include a current sense amplifier configured to output a current sense signal over a present switching cycle based on an inductor current through an inductor, a voltage error amplifier configured to output an error voltage based on a difference between a reference voltage and an output voltage, and a PWM controller. The PWM controller may include an error voltage modifier circuit configured to selectively output the error voltage or a modified error voltage based on a mode signal, and an iterative average current control circuit configured to generate a PWM signal based on the output from the error voltage modifier circuit, the current sense signal over the present switching cycle and a current sense signal over a previous switching cycle that precedes the present switching cycle.

Abstract: A multi-mode converter using iterative average current mode pulse width modulation (PWM) control is provided. The converter may include a current sense amplifier configured to output a current sense signal over a present switching cycle based on an inductor current through an inductor, a voltage error amplifier configured to output an error voltage based on a difference between a reference voltage and an output voltage, and a PWM controller. The PWM controller may include an error voltage modifier circuit configured to selectively output the error voltage or a modified error voltage based on a mode signal, and an iterative average current control circuit configured to generate a PWM signal based on the output from the error voltage modifier circuit, the current sense signal over the present switching cycle and a current sense signal over a previous switching cycle that precedes the present switching cycle.

Abstract: A high power-factor buck-boost converter having a rectified low-frequency AC line voltage input and a DC output is provided. The converter may include a magnetic element, a controlled switch having a gate terminal and a drain terminal that is coupled to the magnetic element, a rectifier diode coupled to the magnetic element, an output smoothing capacitor coupled to the rectifier diode, and a control circuit having an output coupled to the gate terminal of the controlled switch for repeatedly turning the controlled switch off for a first time duration and on for a second time duration. The second time duration may be determined as a function of the first time duration immediately preceding the second time duration.

Abstract: The invention relates to methods for supplying current to an auxiliary power supply for the control circuit of a switching regulator. The auxiliary power supply is connected in parallel to a first switch of the switching regulator. The auxiliary power supply comprises a second switch. During the nonswitching stage of the switching regulator, the second switch has significant impedance so as to power up the auxiliary power supply gradually and to suppress the flow of large or oscillatory currents which may cause damage or create interference. During the switching stage of the switching regulator, the second switch has negligible impedance so as to avoid undue dissipation within the path for the supply of current.

Abstract: A high power-factor buck-boost converter having a rectified low-frequency AC line voltage input and a DC output is provided. The converter may include a magnetic element, a controlled switch having a gate terminal and a drain terminal that is coupled to the magnetic element, a rectifier diode coupled to the magnetic element, an output smoothing capacitor coupled to the rectifier diode, and a control circuit having an output coupled to the gate terminal of the controlled switch for repeatedly turning the controlled switch off for a first time duration and on for a second time duration. The second time duration may be determined as a function of the first time duration immediately preceding the second time duration.

Abstract: A circuit and method are provided detecting a persistent short circuit in a power MOSFET for the purpose of protecting a load from over-current.

Abstract: The invention relates to the control of auxiliary power supply connected in parallel with a switch of a switching regulator. A switch and a diode are included within the connection to the auxiliary supply. The auxiliary supply switch enables a flow of current to the auxiliary supply when the auxiliary supply switch is on and the switch in parallel is off. The auxiliary diode prevents a reverse flow of current when the switch in parallel is on. The auxiliary power supply is suitable to supply of current in both stages of switching regulator operation, to configurations with a common node carrying either type of potential, steady or switching, provides supply of current at high efficiency in the switching stage of switching regulator operation, and provides high efficiency over a wide range of operating conditions of the switching regulator.

Abstract: A communication method and apparatus that uses modulation of post-conduction oscillation frequency in switching converters is provided. The apparatus may include a converter having a magnetic element having a primary winding and a secondary winding, a first switch, a control circuit configured to repeatedly activate the first switch to couple an input voltage source to the primary winding to store electrical energy in the magnetic element, and a diode coupled to the secondary winding, said diode configured to couple the secondary winding to a load to deliver the electrical energy stored in the magnetic element, and a communication apparatus having a second switch, a first modulator capacitor coupled to the secondary winding, a first transmitter configured to activate the second switch in accordance with a first input signal, and a first receiver configured to detect a post-conduction oscillation frequency of a voltage signal at the primary or secondary windings.

Abstract: A comparator sense input is disconnected from a current sense resistor for the duration of a switching transition in an adjacent channel(s). Instead, the sense input receives a signal of the magnitude and the slew rate sampled prior to the transition.

Abstract: A communication method and apparatus that uses modulation of post-conduction oscillation frequency in switching converters is provided. The apparatus may include a converter having a magnetic element having a primary winding and a secondary winding, a first switch, a control circuit configured to repeatedly activate the first switch to couple an input voltage source to the primary winding to store electrical energy in the magnetic element, and a diode coupled to the secondary winding, said diode configured to couple the secondary winding to a load to deliver the electrical energy stored in the magnetic element, and a communication apparatus having a second switch, a first modulator capacitor coupled to the secondary winding, a first transmitter configured to activate the second switch in accordance with a first input signal, and a first receiver configured to detect a post-conduction oscillation frequency of a voltage signal at the primary or secondary windings.

Abstract: A switching power converter has an input voltage source. An output load is coupled to the input voltage source. An inductive element is coupled to the load. A switch is coupled to the inductive element. A control circuit is coupled to the switch and the inductive element for activating and deactivating the switch, the control circuit activating and deactivating the switch based on a negative voltage drop across a resistive element of the control circuit.

Abstract: The invention relates to methods for supplying current to an auxiliary power supply, where the auxiliary supply is connected in parallel to a first switch of a switching regulator and the parallel connection of the auxiliary supply comprises a diode and a second switch.

Abstract: A circuit and method are provided detecting a persistent short circuit in a power MOSFET for the purpose of protecting a load from over-current.

Abstract: A comparator sense input is disconnected from a current sense resistor for the duration of a switching transition in an adjacent channel(s). Instead, the sense input receives a signal of the magnitude and the slew rate sampled prior to the transition.

Abstract: A switching power converter has an input voltage source. An output load is coupled to the input voltage source. An inductive element is coupled to the load. A switch is coupled to the inductive element. A control circuit is coupled to the switch and the inductive element for activating and deactivating the switch, the control circuit activating and deactivating the switch based on a negative voltage drop across a resistive element of the control circuit.

Abstract: The invention relates to auxiliary power supplies.

Abstract: An electronic circuit and method for sampling negative coil current in a power converter includes a zero crossing detector and a sample-and-hold circuit. A switch determines whether a charging or discharging current is flowing through a coil.

Abstract: A flyback power supply method and apparatus is disclosed. An apparatus according to aspects of the present invention includes an energy transfer element having a primary winding and first and second output windings. The first and second output windings are coupled to produce first and second output values, respectively. A primary switch is coupled to the primary winding. A control circuit is coupled to the primary switch to regulate a sum of the first and second output values. A steering circuit having first and second output switches is also included. The first and second output switches are coupled to the first and second output windings, respectively, to regulate a ratio of the first output value to the second output value. The first output switch is coupled to block current through the first output winding and the second output switch is coupled to block current through second output winding. At least one of the first and second output switches is coupled to be closed when the primary switch is opened.

Abstract: A flyback power supply method and apparatus is disclosed. An apparatus according to aspects of the present invention includes an energy transfer element having a primary winding and first and second output windings. The first and second output windings are coupled to produce first and second output values, respectively. A primary switch is coupled to the primary winding. A control circuit is coupled to the primary switch to regulate a sum of the first and second output values. A steering circuit having first and second output switches is also included. The first and second output switches are coupled to the first and second output windings, respectively, to regulate a ratio of the first output value to the second output value. The first output switch is coupled to block current through the first output winding and the second output switch is coupled to block current through second output winding. At least one of the first and second output switches is coupled to be closed when the primary switch is opened.

Abstract: The invention is related to methods and apparatus for driving transistors. One embodiment includes a driver circuit that can drive power transistors at relatively high switching speeds, which can advantageously decrease the size of associated electronics systems that use the driver circuit and power transistors. Embodiments of the invention can drive a switching device that needs a negative voltage bias in order to be shut off. For example, the switching device can correspond to a junction field effect transistor (JFET). Advantageously, one embodiment of the invention can drive such switching devices on and off from a single positive voltage supply.