Marvell International Limited

Marvellworld Trade Ltd.

Semtech Corporation

Hao Peng

Wanfeng Zhang

Jinho Choi

Tuyen Doan

Biing Long Shu

Chin Chang

A method includes generating output power based on a switching signal, comparing the output power to a target power, increasing the output power using a pulse frequency modulation (PFM) and pulse width modulation (PWM) when the output power is less than the target power, and decreasing the output power using the PFM and PWM when the output power is greater than the target power. An apparatus includes a power regulator configured to generate output power based on a switching signal, and a pulse frequency and width modulation (PFWM) controller coupled to the power regulator, and configured to compare the output power to a target power and to increase or decrease the output power using a PFM and pulse PWM according to the comparison result.

Pfm-pwm control for power regulators

A first filter outputs a first signal in response to receiving an input signal. The first signal has a first state in response to the input signal reaching a first threshold voltage on a leading edge of the input signal, and a second state in response to the input signal reaching the first threshold voltage on a trailing edge of the input signal. A second filter outputs a second signal in response to receiving the input signal. The second signal has the first state in response to the input signal reaching a second threshold voltage on the leading edge of the input signal, and the second state in response to the input signal reaching the second threshold voltage on the trailing edge of the input signal. A detection circuit determines, based on times when the first and second thresholds are reached, whether the input signal is received from a triac.

Line voltage detection circuit

Aspects of the disclosure provide a method that including receiving a sensed signal corresponding to a current flowing through an energy transfer module in response to an on/off state of a forward-type triode for alternating current (TRIAC), determining the TRIAC on/off state based on the sensed signal, and controlling the energy transfer module based on the determined TRIAC on/off state.

Method and apparatus for controlling TRIAC dimmable device

An apparatus includes an energy storage device, a driver circuit configured to receive energy from the energy storage device, and a bleed circuit configured to reduce an amount of the energy received by the driver circuit from the energy storage device. The bleed circuit is configured to reduce the amount of the energy received by the driver circuit during a startup period. The energy storage device may include a transformer, the driver circuit and bleed circuit being coupled to first and second windings of the transformer, respectively. A method includes receiving, by a driver circuit, energy from an energy storage device, and reducing, using a bleed circuit, the energy received by the driver circuit during a startup period. The energy storage device may include a transformer, the driver circuit and bleed circuit being coupled to first and second windings of the transformer, respectively.

Overshoot prevention for deep dimming startup

Aspects of the disclosure provide a circuit that includes a controller. The controller is configured to receive a signal indicative of a current flowing in a magnetic component and control a switch in connection with the magnetic component to shape a peak current of the current flowing in the magnetic component. The controller shapes the peak current from a first peak current level to a second peak current level in order to reduce an amplitude of a ripple in a current drawn from a triode for alternating current (TRIAC) during a time to satisfy a holding current requirement of the TRIAC.

Current shaping scheme in TRIAC dimmable LED driver

Aspects of the disclosure provide a method. The method includes determining a power adjustment to a load, determining whether a switching frequency of a pulse width modulation (PWM) signal is within a specific range, and adjusting the switching frequency of the PWM signal based on the power adjustment to control power transfer to the load. The switching frequency is adjusted to remain in the specific range.

Method and apparatus for controlling a power adjustment to a lighting device

Aspects of the disclosure provide a method. The method includes regulating a time for turning on a switch to transfer energy via a transformer in a first control mode, determining a turn-on time for a second control mode based on the regulated time in the first control mode, and controlling the switch based on the determined turn-on time in the second control mode to transfer energy via the transformer.

Method and apparatus for turning on a lighting device

Embodiments include circuits and methods to determine peak current for current regulation. A control signal circuit monitors a current on the primary side of a transformer based a turn on time of a switch coupled to the primary side. The control signal circuit determines whether the monitored current exceeds an over-current protection threshold, and determines a duration that the monitored current exceeds the over-current protection threshold. The control signal circuit determines a peak primary current in the primary side based on the over-current protection threshold, the duration that the monitored current exceeds the over-current protection threshold, and the turn on time of the switch. The control signal circuit controls the turn on time for the switch based on the determined peak primary current.

Circuits and methods for determining peak current

Power lighting control methods and systems for solid state lighting are disclosed. For example, a power control system includes a transformer that includes a primary coil configured to receive a first voltage based on an output of a switching circuit, a secondary coil configured to generate a first current based on the first voltage to power a solid-state load, and a bleeder coil coupled to a bleeder switch, and a control module that causes the bleeder switch to turn on incrementally during a dimming event over M power cycles, where M is a positive integer, so as to eliminate or reduce a current step in the first current provided to the solid state load.

Soft bleeder to remove step dimming

In various embodiments, there is provided a method comprising receiving a waveform; rectifying the waveform to generate a rectified waveform; comparing the rectified waveform with a first voltage to generate a first compare signal, wherein a first edge of the first compare signal occurs at a first time when an instantaneous value of the rectified waveform becomes higher than the first voltage; comparing the rectified waveform with a second voltage to generate a second compare signal, wherein a first edge of the second compare signal occurs at a second time when the instantaneous value of the rectified waveform becomes higher than the second voltage; and based at least in part on the first time and the second time, estimating a voltage of the waveform.

Alternating current (AC) line voltage determination

Aspects of the disclosure provide a method. The method includes receiving an input voltage rectified from an alternating current (AC) power supply, detecting a time duration that the input voltage is between a first threshold voltage and a second threshold voltage, determining a line voltage of the AC power supply based on the time duration, and regulating a time for turning on a switch to transfer energy via a transformer based on the detected line voltage.

Method and apparatus for starting up

A system including a switch configured to supply power to a load. A first comparator is configured to compare a first current through the switch to a first threshold. A second comparator is configured to compare the first current through the switch to a second threshold. The second threshold is greater than the first threshold. A current control module is configured to turn off the switch (i) for a first duration in response to the first current through the switch being greater than or equal to the first threshold and (ii) for a second duration in response to the first current through the switch being greater than or equal to the second threshold. The current control module is configured to adjust the second duration based on a difference between an estimated current through the load and a desired current through the load.

Two-peak current control for flyback voltage converters

Methods, circuits, and systems for determining the presence of a chopped input signal are disclosed. A digital signal generator can produce multiple digital signals when an alternating current (AC) signal input reaches multiple threshold voltages. The times at which the threshold voltages are reached can be determined by looking at the times at which the digital signals go high and low. The differences between the times at which the digital signals go high and low are used to determine if the AC signal input is a leading or trailing edge chopped signal. The AC input signal is a leading edge chopped signal when the difference between the times at which the digital signals go high is less than a predetermined time threshold, and is a trailing edge chopped signal when the difference between the times at which the digital signals go low is less than a predetermined time threshold.

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Sunnyvale, CA, United States of America

Hao Peng