Maxim Integrated Products, Inc.

Suresh Hariharan

Ron Vincent Ocampo

Ramesh Selvaraj

Gianluca Mariano

Alfons Willy Leo Janssen

Gregory Michael Fattig

Described are light emitting diode (LED) and non-LED driver systems and methods that reduce current overshoot and, deadtime, and other undesirable effects in applications such as adaptive driving beam headlamp application that negatively impact circuit parameters, including efficiency. In certain embodiments, this is accomplished by using a current clamp circuit that is controlled such as to limit an overshoot in load current, e.g., when a number of LEDs that are turned on changes.

H-bridge buck-boost for adaptive driving beam headlamps

Presented are systems and methods for improving transient response in buck-boost circuits avoid circuit instabilities in both boost mode and buck mode. In embodiments, this is accomplished when, in response to determining that the circuit operates in buck mode, a compensation circuit is adjusted to operate at a first bandwidth. In response to determining that the circuit operates in boost mode, the compensation circuit may then be adjusted to decrease a boost mode crossover frequency and operate at a second, lower bandwidth.

Systems and methods for improving transient response in H-bridge buck-boost drivers

Presented are systems and methods for controlling a compensation circuit. In embodiments, a detection circuit receives a set of control signals that have been generated by a control circuit to drive a set of light emitting diode (LED) switches. The switches control a set of LEDs driven by a DC-DC converter that is coupled to a feedback loop to which the compensation circuit is removably coupled. In embodiments, the detection circuit determines whether the status of an LED is about to change and, in response, uses the compensation circuit to control the feedback loop in a manner such as to reduce a current overshoot or current undershoot in the LED current.

Systems and methods for improving transient response in H-bridge buck-boost drivers using integrated matrix manager

Presented are average current mode control systems and methods for driving a load with a constant current. In embodiments, this is accomplished when, in response to a zero-current detection circuit detecting a zero current condition in the load current, a compensation circuit is disconnected from a first error amplifier to enable that error amplifier to provide a first voltage to a second error amplifier. The second error amplifier increases a charging current in a capacitor to reduce a dead time in the load current. Similarly, in response to an overcurrent detection circuit detecting an overcurrent condition in the load current, the compensation circuit is disconnected from the first error amplifier to enable the first error amplifier to provide a second voltage to the second error amplifier to decrease the charging current and reduce an overshoot condition.

Systems and methods for improving transient response in slew-rate limited H-bridge buck-boost drivers

Described herein are systems and methods for generating short load current pulses using an H-bridge. In various embodiments, this is accomplished by controlling, in a shunting mode, a low-side switch of the H-bridge to drive a first average current and controlling, in a non-shunting mode, a high-side switch of the H-bridge to drive a second average current such that the first and second average currents are substantially the same and reduce a current pulse width of the load current.

Narrow pulse widths in h-bridge buck-boost drivers

The present disclosure relates generally to systems and methods for transient response improvements in electrical circuits. More particularly, the present disclosure relates to systems and methods for suppressing overshoot currents and overshoot durations in circuits using switching regulators, such as driver circuits for LED applications. Embodiments of the invention relate to an LED driver that utilizes transient suppression systems and method for LED applications.

Transient suppression systems and methods in electrical circuits

Described herein are systems and methods for operating DC-DC regulators such as LED drivers. Various embodiments herein allow a DC-DC regulator to switch between buck mode and buck-boost mode without suffering effects otherwise resulting from transient currents when switching between modes. In certain embodiments, this is accomplished by operating the DC-DC regulator in a buck-boost mode to charge a boost capacitor with a substantially constant inductor current. The inductor current is also used to control a set of switches to operate the DC-DC regulator in a buck mode to drive a load by using the capacitor as a power source.

Control circuit for improving infrared (IR) emitter storage capacitor utilization

Described herein are embodiments for systems and methods LED driver. In one or more embodiments, the LED driver may operate in a boost mode to charge a capacitor using a power source or in a boost mode to use the charged capacitor to provide current to a load, such as an LED string. In one or more embodiments, the LED driver uses a single inductor for boost mode operation or buck mode operation. Such embodiments simplify the LED driver and therefore provide an economic advantage. In one or more embodiments, the power source is disconnected in the buck mode, such that the capacitor may be discharged to a low voltage. Therefore, the capacitor may need smaller capacitance to deliver the same discharge energy which otherwise requires a capacitor with larger capacitance.

LED driver systems and methods

A new architecture for buck LED drivers and buck DC-DC converters is disclosed for providing response to both line and loads. The architecture uses a new average current mode control scheme that does not use an error amplifier to regulate the current in the inductor in the buck converter. Even though there is no oscillator the switching frequency remains constant over line and load. The architecture provides a low cost solution with very fast response times.

Average current mode control architecture

An apparatus and method provides a driver circuit that provides for power factor correction (PFC) to a load, such as a solid-state lighting (SSL) device, such as, for example, a light emitting diode (LED) or an array or cluster of LEDs. A programmable reference is provided in the circuit to operate in a fixed frequency peak current mode control (FFPCMC) or in a fixed frequency average current mode control (FFACMC). A driver circuit is employed to operate the SSL device using power derived from a main power source which may be DC or AC. In a FFPCMC embodiment, a programmable power reference is programmed to be a fixed DC voltage. In a FFACMC embodiment, source input current to the circuit can be programmed to be proportional to the rectified AC voltage after a bridge rectifier.

Power factor correction in and dimming of solid state lighting devices

A system includes a driver circuit, a modulator circuit, and a reset circuit. The driver circuit drives a plurality of light emitting diodes via a switch. The switch is controlled by a first signal having a first frequency. The driver circuit controls brightness of the light emitting diodes based on a second signal including a plurality of pulses. The modulator circuit modulates the first signal using a direct sequence spread spectrum modulation. The direct sequence spread spectrum modulation uses a sequence generated based on the first signal. The reset circuit resets the modulator circuit at each of the plurality of pulses of the second signal. The modulator circuit repeats the sequence at each of the plurality of pulses of the second signal.

Eliminating flicker in LED-based display systems

Various embodiments of the invention allow LED lamp fixtures to pass EMI testing irrespective of whether the lamp fixture is operated by a magnetic transformer or an electric transformer without causing input current waveform distortion and without defeating transformer compatibility. In certain embodiments, the type of transformer is determined based on detecting characteristic voltage waveforms and based that determination an EMI filter is automatically switched in and out of the lamp circuit.

LED lighting system and method

The invention relates to a light emitting diode (LED) illumination system, and more particularly, to systems, devices and methods of rapidly ramping up a transformer current and a LED driver current by coupling a transformer load compensation circuitry to an output of an electronic transformer. A bridge rectifier is coupled to the electronic transformer and provides full-wave rectification to an AC supply at the output of the electronic transformer. The load compensation circuitry senses the rectified AC supply and compensates the load of the electronic transformer, such that the electronic transformer starts up properly when the level of the signal envelope is below a threshold voltage. Therefore, the load compensation circuit is active for a programmed time during which the LED driver current has been increased to a sufficient value to keep the electronic transformer operational.

Load compensation for an electronic transformer in a LED illumination system

Embodiments of the present invention provide a system and method for determining a magnitude of current driving LEDs by sensing a current through a switching transistor and extracting the information of the LED current based on a relationship between the current through the switching transistor and the current driving the LEDs.

Current sensing for LED drivers

Various embodiments of the invention provide power factor correction in solid state lighting applications. In certain embodiments, an LED driver for an LED array is controlled for power factor correction by a control circuit block. The control circuit block comprises electronic circuitry that enables the input current to the LED driver to be measured and controlled. This control circuit block comprises at least one switching device that enables an alternating form of current at a particular frequency to be applied to the LED array regardless of whether the main power source is a DC or AC power source.

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Livermore, CA, United States of America

Suresh Hariharan