Dialog Semiconductor Gmbh

Iwatt Inc.

Semiconductor Components Industries, LLC

Fairchild Semiconductor Corporation

Enzhu Liang

Xuecheng Jin

Ming Gu

Minjong Kim

Yuwen Wang

John William Kesterson

Kaiwei Yao

Xiaoyan Wang

Andrey B Malinin

Jiang Chen

Selcuk Sen

A multi-phase power supply includes a plurality of phase controllers each driving a first terminal of a respective inductor alternatively between an input voltage and a ground voltage to regulate an output voltage in a work mode, keeping the first terminal of the respective inductor in a high impedance state during a non-work mode, having an input for receiving an enable signal for selecting between the work mode and the non-work mode, and generating a current monitor signal to represent a current through the respective inductor during both the work mode and the non-work mode, and a controller coupled to each phase controller for selectively enabling respective ones of the phase controllers in response to a load demand, receiving the current monitor signal from each phase controller, and selectively shutting down the multi-phase power supply when a total of current monitor signals from the phase controller exceeds a threshold.

Inductor current emulation for output current monitoring

A switch mode power supply controller includes a switch terminal adapted to be coupled to an inductor that drives a load, high- and low-side switches a pulse width modulation (PWM) circuit, and a current monitor circuit. The PWM circuit is coupled to a feedback terminal for receiving a feedback signal, and alternatively drives the high-side switch and the low-side switch with a duty cycle set using the feedback signal to regulate an output voltage to a desired level in a work mode, and keeps both the high-side switch and the low-side switch non-conductive in a non-work mode. The current monitor circuit provides a current monitor signal representative of a current driven from the inductor to the load, wherein the current monitor circuit forms the current monitor signal by measuring an inductor current during a work mode, and by emulating the inductor current during a non-work mode.

The embodiments disclosed herein describe a set of fault detection circuits for LED circuits in an LED channel. A first fault detection circuit is configured to detect a short fault across one or more LEDs. A second fault detection circuit is configured to detect an open fault across an LED. A third fault detection circuit is configured to detect a short across an LED channel transistor. A fourth fault detection circuit is configured to detect an LED channel sense resistor open fault. A fifth fault detection circuit is configured to detect if the LED channel is being intentionally unused. These fault detect circuits can be implemented in a fault detection integrated circuit coupled to the LED channel.

LED driver with comprehensive fault protections

An LED (Light Emitting Diode) controller comprises a first LED driver to generate a first PWM (Pulse Width Modulation) drive signal to turn on or turn off, respectively, a first current through a first LED string. Additionally, the LED controller comprises a compensation circuit to generate the first PWM drive signal responsive to a first duty set signals. The first duty set signal is indicative of a first duty cycle set for the first PWM drive signal. The compensation circuit receives a first feedback signal indicative of the first current, generates a first error signal indicative of a difference between a first predetermined target value and the first feedback signal, and generates the first PWM drive signal to have the first duty cycle corresponding to the first duty set signal and further adjusted by the first error signal.

Modifying duty cycles of PWM drive signals to compensate for LED driver mismatches in a multi-channel LED system

An LED driver controls current through an LED string. The LED driver generates a boosted PWM signal to drive a PWM transistor in the LED current path such that the PWM transistor maintains a substantially constant V, thus minimizing turn-on impedance of the PWM transistor. A current mirror circuit controls peak LED current when the PWM transistor is on. A trimming circuit includes a set of programmable switches to couple or decouple trimming transistor from the LED current path, and allowing for fine calibration of the LED current. By maintaining a low resistance and compensating for current mismatch in the LED current path, the LED driver provides efficient power performance and robustness that is particularly beneficial in high current applications.

High performance adaptive switched LED driver

A system controls a switching power converter to power LED strings using a predictive feedforward control mechanism. An LED controller determines programmed current levels and duty cycles for driving LED strings. The LED controller determines a predicted load for a subsequent cycle of a switching power converter driving the LED strings based on the programmed current levels and duty cycles. A power conversion controller uses the predicted load information to control switching of the switching power converter. This improves the dynamic response of the switching converter to changing load conditions, thereby improving overall power efficiency and performance of the system.

Predictive control of power converter for LED driver

A system that provides an intelligent approach to driving multiple strings of LEDs. A processing device determines an optimal current level for each LED string from a limited set of allowed currents. The processing device also determines a PWM duty cycle for driving the LEDs in each LED string to provide precise brightness control over the LED string. The settings for the current level and duty cycle are transmitted to an LED driver for regulating the current and on-off times of the LED strings. Beneficially, the system reduces the size of the LED driver while leveraging existing resources available in the processing device to operate the LEDs in a power efficient manner.

Adaptive switch mode LED system

A start-up circuit in a switch-mode power converter that employs a Zener diode to provide a reference voltage to reduce the power consumption and the size of the start-up circuit. The start-up circuit also includes a coarse current source and a coarse reference voltage signal generator for producing current and reference voltage for initial startup operation of a bandgap circuit. The reference signal and current from coarse current source and the reference voltage signal generator are subject to large process, voltage and temperature (PVT) variations or susceptible to noise from the power supply, and hence, these signals are used temporarily during start-up and replaced with signals from higher performance components. After bandgap circuit becomes operational, the start-up receives voltage reference signal from the bandgap circuit to more accurately detect undervoltage lockout conditions.

Low power consumption start-up circuit with dynamic switching

A reference buffer includes a first current mirror, a second current mirror, a first source follower coupled in series to a branch of the first current mirror and receiving a first initial reference voltage and outputting a first reference voltage, a second source follower coupled in series to a branch of the second current mirror and receiving a second initial reference voltage and outputting a second reference voltage, and a resistor coupled between a first node and a second node outputting the first and second reference voltages, respectively. The first node is disposed between the first current mirror and the first source follower and the second node is disposed between the second current mirror and the second source follower. The voltage difference between the first reference voltage and the first initial reference voltage is substantially same as that between the second reference voltage and the second initial reference voltage.

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Enzhu Liang