Diodes Inc.

Texas Instruments Corporation

Other

Dongjie Cheng

John Huang

Vijay Hugar

Sumit Bhat

Joy Das

Juergen Luebbe

Joao Carlos Brito

Joao Carlos Felicio Brito

Arvind Patil

Harish Raikar

Akshay Panchamukhi

An apparatus includes a clamping circuit configured to provide a predetermined voltage at an output of the clamping circuit, a clamping switch coupled to the output of the clamping circuit, and a pass device connected between the clamping switch and an input/output terminal of a controller.

Fault diagnosis apparatus and method

An apparatus includes a plurality of MOSFET device groups connected in parallel, wherein a first common node of the plurality of MOSFET device groups is coupled to a cathode of a light emitting diode channel of a plurality of light emitting diode channels, and a second common node of the plurality of MOSFET device groups is connected to ground, and a control circuit configured to generate gate drive signals for the plurality of MOSFET device groups, wherein the gate drive signals are configured to adjust a current flowing through the light emitting diode channel based on a predetermined color and a predetermined brightness level of the light emitting diode channel, and under different duty cycles, the control circuit is configured to control the current flowing through the light emitting diode channel to be proportional to a corresponding duty cycle.

LED color and brightness control apparatus and method

An apparatus includes a bandgap voltage reference configured to generate a current reference for controlling a plurality of light emitting diode channels, a plurality of MOSFET devices connected in parallel and coupled between a cathode of a light emitting diode channel and ground, wherein the plurality of MOSFET devices is configured to control a current flowing through the light emitting diode channel, and a control circuit configured to generate gate drive signals for the plurality of MOSFET devices, wherein the gate drive signals are configured to adjust the current flowing through the light emitting diode channel based on a predetermined color and a predetermined brightness level of the light emitting diode channel.

A controller for controlling a plurality of serially-connected LED strings includes a reference voltage generator configured to generate a plurality of reference voltages. The reference voltage generator is further configured to vary the plurality of reference voltages based on a sampled voltage signal. The sampled voltage signal can include one or both of a peak voltage of the rectified input AC voltage and a peak voltage of an LED diode forward voltage Vf. The controller further includes a plurality of linear regulators, each linear regulator coupled between a cathode of a corresponding LED string and a common current sense node, and each linear regulator is configured to regulate a current through a corresponding LED string according to a corresponding reference voltage.

Constant current linear driver with high power factor

A reverse current sensing (RCS) regulator system and method is provided. One embodiment of the invention includes a RCS regulator system. The system comprises a RCS comparator that monitors a drain voltage of a LS FET and is configured to switch states at a zero crossing point to provide an indication of the start of a reverse current condition. The system further comprises a RCS evaluator that measures a drain voltage of the LS FET upon receiving an indication that the LS FET has been turned off by the driver logic circuit and adjusts an offset to the RCS comparator to adjust the trip point of the RCS comparator relative to the drain voltage if the measured drain voltage falls outside a predetermined threshold.

Reverse current sensing regulator system and method

A switching regulator () including an on-chip power output function () and also an interface () to which off-chip power output devices (PU,PD) may be connected is disclosed. The switching regulator () includes an output enable circuit () that senses the presence of external components at one of the terminals (T_PD, TL) of the on-chip power output function () or of the interface () to determine which of the output functions to enable. In one disclosed embodiment, the output enable circuit () detects whether an off-chip power transistor (T_PD) is connected at the interface (), by charging a passive circuit (R, C) and determining whether the charging time constant is affected by the gate capacitance of the external transistor (PD). In another disclosed embodiment, the output enable circuit () detects whether a load (L) is connected to the output of the on-chip power output function () by measuring the voltage across a resistor (R), into which a mirrored current is sourced, based on a current applied to the external terminal (TL); if the load (L) is present, the voltage across the resistor (R) will cause a logic transition to enable the on-chip power output function ().

Regulator with automatic power output device detection

One embodiment of the invention includes a hysteretic power regulator system. The system includes a switching stage configured to periodically couple an input voltage to an inductor in response to a control signal to generate an output voltage. The system also includes a hysteretic control stage configured to generate the control signal based on a comparison of a feedback voltage associated with the output voltage and a predetermined reference voltage. The system also includes a feed-forward stage configured to generate a feed-forward ramp voltage in response to the control signal. The feed-forward ramp voltage can be added to the feedback voltage to set a frequency of the control signal. The system further includes a compensation stage configured to cancel a DC error associated with the feed-forward ramp voltage relative to the feedback voltage to substantially mitigate errors associated with the output voltage.

Growing community of inventors

Murphy, TX, United States of America

Dongjie Cheng