Marvell International Limited

Marvellworld Trade Ltd.

Agere Systems Inc.

Jianqing Lin

Hubertus Notohamiprodjo

Sehat Sutardja

Wanfeng Zhang

Shaoan Dai

Xiaopeng Chen

Hong Liang Zhang

Roy Baxter Blake

Chun Wang

A controller for a power conversion circuit that includes an inductor, a diode, and a switch. The controller includes a counter configured to determine, based on a first voltage input to the inductor, an on-time of the diode. The on-time of the diode corresponds to an amount of time that the diode is conducting a first current to a load of the power conversion circuit. A current estimation circuit configured to estimate, based on the on-time of the diode and an on-time of the switch, an output current of the power conversion circuit. The on-time of the switch corresponds to an amount of time that the switch is conducting a second current. A pulse width modulator is configured to provide, based on the estimated output current, a gate drive signal to the switch. The gate drive signal selectively transitions the switch between an on state and an off state.

Systems and methods for estimating an output current of a power conversion circuit

A controller including a switch, a first module, a second module, and a control module. The switch receives current from an inductor and bypasses a portion of the current from being received by a load. The switch is cycled between a first state and a second state at a frequency. The first module, for a first cycle of the switch, determines a first amount of time the switch is in the first state. The second module, based on the first amount of time, determines a second amount of time for a level of the current to decrease to a predetermined level. The second amount of time begins during the first cycle and when the switch transitions from the first state to the second state. The control module, based on the second amount of time and prior to the current decreasing to the predetermined level, changes the frequency of the switch.

Method and apparatus for changing a frequency of a switch prior to a level of current received from an inductor decreasing to a predetermined level

A power conversion circuit comprising a voltage estimation circuit, a current estimation circuit, and a pulse width modulation circuit. The voltage estimation circuit is configured to receive a voltage corresponding to an input of an inductor of the power conversion circuit and generate an estimate of an output voltage of the power conversion circuit based on the voltage. The current estimation circuit is configured to receive a current corresponding to a switch connected in series with the inductor and generate an estimate of an output current of the power conversion circuit based on the current. The pulse width modulation circuit is configured to produce a pulse width modulated signal based on the estimate of the output voltage and the estimate of the output current.

Intelligent switching controller and power conversion circuits and methods

A boost converter comprises an inductance that receives an input signal. A switch controls current supplied by the inductance to a load. A power factor control module comprises a mode control module that selects an operating mode of the boost converter and a switch control module that switches the switch at a frequency. The frequency is equal to a first frequency when the mode control module selects a continuous mode and equal to a second frequency when the mode control module selects a discontinuous mode. The first frequency is greater than the second frequency.

Power factor control systems and methods

Apparatuses, methods, systems, and circuits for light-emitting diode (LED) control are disclosed. In one embodiment, an LED control circuit can include a first pin receiving an input voltage supply; a second pin receiving a primary signal from a primary winding of a transformer coupled to the LED; a third pin coupled to a ground supply; and logic configured to estimate an output current and/or output voltage at the LED coupled to a secondary winding of the transformer from the input voltage supply and the primary signal.

Light-emitting diode (LED) driver and controller

In one embodiment, the present invention includes a circuit having a voltage estimation circuit to receive a first voltage and generate an estimation of an output voltage of a power conversion circuit based on the first voltage. The first voltage is from a circuit node between a first terminal of a switch and a first terminal of an inductor. The circuit further comprises a current estimation circuit to receive a first current and generate an estimation of an output current of the power conversion circuit based on the first current. The first current is a current through the switch. The circuit further includes a pulse width modulation circuit to produce a pulse width modulated signal based on the estimation of an output voltage and the estimation of an output current.

Circuits, systems, methods and software for controlling a power conversion and/or correcting and/or controlling a power factor in such conversion(s). The present invention generally takes a computational approach to reducing or minimizing zero current periods in the critical mode of power converter operation, and advantageously reduces zero current periods in the critical mode of power converter operation, thereby maximizing the power factor of the power converter in the critical mode and reducing noise that may be injected back into AC power lines. The present power factor controller allows for greater design flexibility, reduced design complexity, and reduced resolution and greater tolerance for error in certain parameter measurements useful in power factor correction and/or control.

Circuits, systems, methods, and software for power factor correction and/or control

In a method and apparatus for controlling power factor correction (PFC) in mixed operation modes, a frequency of the input voltage is obtained by detecting the zero crossing points of the input voltage. A peak of the input voltage is obtained by detecting input voltage with 90 degree phase. Thus, the present invention predicts the input voltage by its frequency and peak and the characteristic of the sine wave. A digital signal processor computes the duty and frequency of a boost switch, switching the operation mode of the boost converter among continuous mode, critical mode and discontinuous mode according to input voltage or the load. According to another aspect, the operation is switched to critical mode from the average current mode when a zero current is detected before the charging and recharging cycle of the boost switch is finished. Overcurrent protection may be achieved by controlling current in response to detected voltage to provide a substantially constant power level. The overcurrent protection may be adaptive in nature. In this aspect, an adaptive driver for a PFC controller reduces the slew rate of signals over the boost switch of the PFC controller. The adaptive driver may have a group of transistors which may be divided into a plurality of branches. The charging current through the boost switch may be increased by turning on an increasing number of branches until the voltage over the switch exceeds a reference voltage, and this may determine the number of branches to drive the boost switch during normal operation.

Method and apparatus for controlling power factor correction

A boost converter comprises an inductance that receives an input signal. A switch controls current supplied via the inductance to a load. A power factor control module comprises a mode control module that selects an operating mode of the boost converter and a switch control module that switches the switch at a frequency. The frequency is equal to a first frequency when the mode control module selects a continuous mode and equal to a second frequency when the mode control module selects a discontinuous mode. The first frequency is greater than the second frequency.

In a method and apparatus for controlling power factor correction in mixed operation modes, a frequency of the input voltage is obtained by detecting the zero crossing points of the input voltage. A peak of the input voltage is obtained by detecting input voltage with 90 degree phase. Thus, the present invention predicts the input voltage by its frequency and peak and the characteristic of the sine wave. A digital signal processor computes the duty and frequency of a boost switch, switching the operation mode of the boost converter among continuous mode, critical mode and discontinuous mode according to input voltage or the load. According to another aspect, the operation is switched to critical mode from the average current mode when a zero current is detected before the charging and recharging cycle of the boost switch is finished. Overcurrent protection may be achieved by controlling current in response to detected voltage to provide a substantially constant power level. The overcurrent protection may be adaptive in nature.

Power factor correction boost converter with continuous, discontinuous, or critical mode selection

In a method and apparatus for controlling power factor correction in mixed operation modes, a frequency of the input voltage is obtained by detecting the zero crossing points of the input voltage. A peak of the input voltage is obtained by detecting input voltage with 90 degree phase. Thus, the present invention predicts the input voltage by its frequency and peak and the characteristic of the sine wave. A digital signal processor computes the duty and frequency of a boost switch, switching the operation mode of the boost converter among continuous mode, critical mode and discontinuous mode according to input voltage or the load. According to another aspect, the operation is switched to critical mode from the average current mode when a zero current is detected before the charging and recharging cycle of the boost switch is finished.

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Pleasanton, CA, United States of America

Jianqing Lin