Advanced Analogic Technologies Incorporated

Impala Linear Corporation

Skyworks Solutions, Inc.

Other

Tlwam LLC

Kevin Peter D'Angelo

Richard Kent Williams

David Alan Brown

Robert Stephen Wrathall

George Adrian Hariman

Jan Nilsson

John Sung K So

Andrew Whyte

Gustavo James Mehas

Charles F Coles

Eddie Lok Chuen Ng

David J Oldham

James Fannin

Matthew Arruda

John K Sung

A multiple-chip voltage feedback technique allows multiple strings of Light Emitting Diodes (LED's) and current sinks to be efficiently powered by a DC-to-DC voltage converter. A plurality of controllers connected in a daisy chain series monitor voltages between the connected LED's and the current sinks, progressively determine the lowest voltage, and then feed the lowest voltage back to the voltage converter. The DC-to-DC voltage converter monitors this lowest voltage and adjusts its output in order to ensure that the LED strings have adequate voltage with which to function, even as the LED's have different forward voltages and the strings are asynchronously enabled and disabled.

System and method for driving light emitting diodes

An LED driver IC for driving external strings of LEDs includes a prefix register and a data register connected in series with each other and with the prefix and data registers in other driver ICs. The prefix and data registers of the driver ICs are connected in a daisy chain arrangement with an interface IC. The interface IC loads data identifying a functional latch into the prefix register and data defining a functional condition into the data register of each driver IC. The data in the data register is then transferred to the functional latch to control the functional condition within the LED driver IC.

Low cost LED driver with improved serial bus

According to one aspect, an integrated circuit to control a power supply that supplies power to a plurality of light-emitting diode (LED) strings is provided. The integrated circuit includes an interface circuit to couple to a plurality of serial shift registers that are coupled in a daisy chain. The interface circuit may be configured to receive a plurality of digital values from the plurality of serial shift registers each corresponding to a voltage level at one end of an LED string of the plurality of LED strings and identify a lowest digital value from the plurality of digital values. The integrated circuit may further includes a converter coupled to the interface circuit that is configured to convert the lowest digital value into a control signal and provide the control signal to the power supply to adjust an output voltage of the power supply.

Serial lighting interface with embedded feedback

A distributed system for driving strings of series-connected LEDs for backlighting, display and lighting applications that includes multiple intelligent satellite LED driver ICs connected to an interface IC via a serial lighting interface bus. The interface IC translates information obtained from a host microcontroller into instructions for the satellite LED driver ICs pertaining to such parameters as duty factor, current levels, phase delay and fault settings. Fault conditions in the LED driver ICs can be transmitted back to the interface IC. An analog current sense feedback system which also links the LED driver ICs determines the supply voltage for the LED strings.

Low cost LED driver with integral dimming capability

An active clamp current sink is used to voltage protect a low voltage rated, high power current sink that drives illumination current through a string of serially connected LEDs. When the LEDs are turned off as part of a PWM configuration, the forward voltage on the LEDs falls, and the voltage presented to the low voltage rated, high power current sink rises. The active clamp current sink monitors the voltage across the high power current sink and ensures that an adequate current flows through the LEDs. This minimally adequate current maintains a sufficiently large forward voltage through the LEDs, and therefore a sufficiently small voltage is presented to the high power current sink.

Active LED voltage clamp

A method of controlling an LED string having a first end coupled to a power source and a second end coupled to a first end of a current sink is provided. The method include generating a target voltage at a first end of an external inductor coupled to the second end of the current sink, comparing the target voltage to a measured voltage at the first end of the external inductor, charging the external inductor responsive to the measured voltage being greater than the target voltage, and discharging the external inductor responsive to the measured voltage being less than the target voltage.

Controlling an LED string using a current sink with low side voltage regulation

A multiple chip voltage feedback technique allows multiple strings of LED's and current sinks to be efficiently powered by a DC-to-DC voltage converter within an appliance. A connected series of differential amplifiers or multiplexers are used to monitor the voltages between the connected LED's and the current sinks, progressively determine the lowest voltage, and then feed the lowest voltage back to the voltage converter. The DC-to-DC voltage converter monitors this lowest voltage and adjusts its output in order to ensure that the strings have adequate voltage with which to function, even as the LED's have different forward voltages and the strings are asynchronously enabled and disabled.

Multiple chip voltage feedback technique for driving LED's

An improved all electronic sensor to detect when a whistle emits an audio signal. The electronic sensor activates an additional function such as a light, or signaling device to activate remote functions, such as submerged speakers, or time keeping apparatus.

Electronic whistle sensor

An LED driver IC for driving external strings of LEDs comprises a prefix register and a data register connected in series with each other and with the prefix and data registers in other driver ICs. The prefix and data registers of the driver ICs are connected in a daisy chain arrangement with an interface IC. The interface IC loads data identifying a functional latch into the prefix register and data defining a functional condition into the data register of each driver IC. The data in the data register is then transferred to the functional latch to control the functional condition within the LED driver IC.

A switching regulator that includes a high-side MOSFET, a low-side MOSFET, a high-side driver circuit, a low-side driver circuit, and a capacitive coupling circuit. An output of the high-side driver circuit is coupled to a gate of the high-side MOSFET to control the high-side MOSFET to be substantially depleted during a first operational phase and to be substantially enhanced during a second operational phase. An output of the low-side driver circuit is coupled to a gate of the low-side MOSFET to control the low-side MOSFET to be substantially enhanced during the first operational phase and to provide a regulated drain-to-source current during the second operational phase. The capacitive coupling circuit is coupled to an input of the high-side driver circuit and the gate of the low-side MOSFET and decreases the regulated drain-to-source current during a transition from the first operational phase to the second operational phase.

Switching regulator with reduced body diode conduction

A system for controlling multiple strings of LEDs includes a group of LED driver IC's, each of which includes a current sense feedback (CSFB) sample latch for storing a digital representation of the forward-voltage drop across a controlled LED string. Each CSFB latch is coupled to a register within a serial lighting interface (SLI) bus that both originates and terminates at an interface IC. As the data on the SLI bus is shifted into the interface IC, the interface IC selects the CSFB word that represents the highest forward-voltage drop of any of the controlled LED strings, which is then used by the interface IC to generate a CSFB signal for setting the appropriate supply voltage for the controlled LED strings.

A single wire serial interface for power ICs and other devices is provided. To use the interface, a device is configured to include an EN/SET input pin. A counter within the device counts clock pulses sent to the EN/SET input pin. The output of the counter is passed to a ROM or other decoder circuit. The ROM selects an operational state for the device that corresponds to the value of the counter. In this way, control states may be selected for the device by sending corresponding clock pulses to the EN/SET pin. Holding the EN/SET pin high causes the device to maintain its operational state. Holding the EN/SET pin low for a predetermined timeout period resets the counter and causes the device to adopt a predetermined configuration (such as off) until new clock pulses are received at the EN/SET pin.

Single wire serial interface

A system for controlling multiple strings of LEDs includes a group of LED driver ICs, each of which includes a current sense feedback (CSFB) sample latch for storing a digital representation of the forward-voltage drop across a controlled LED string. Each CSFB latch is coupled to a register within a serial lighting interface (SLI) bus that both originates and terminates at an interface IC. As the data on the SLI bus is shifted into the interface IC, the interface IC selects the CSFB word that represents the highest forward-voltage drop of any of the controlled LED strings, which is then used by the interface IC to generate a CSFB signal for setting the appropriate supply voltage for the controlled LED strings.

An integrated circuit for controlling a boost converter. The integrated circuit includes a gate pin, a source pin, a feedback pin, a current mirror sub-circuit, and a control sub-circuit. The current mirror sub-circuit is connected to the source pin to produce an output current from a reference current flowing between the source pin and ground, the reference current being larger than the output current. The control sub-circuit is connected to the current mirror sub-circuit, the gate pin and the feedback pin to control a gate voltage provided to the gate pin based on the output current and a feedback voltage at the feedback pin.

Integrated circuit for controlling an inductive boost converter

A distributed system for driving strings of series-connected LEDs for backlighting, display and lighting applications includes multiple intelligent satellite LED driver ICs connected to a an interface IC via serial bus. The interface IC translates information obtained from a host microcontroller into instructions for the satellite LED driver ICs pertaining to such parameters as duty factor, current levels, phase delay and fault settings. Fault conditions in the LED driver ICs can be transmitted back to the interface IC. An analog current sense feedback system which also links the LED driver ICs determines the supply voltage for the LED strings.

Growing community of inventors

Carmel, CA, United States of America

Kevin Peter D'Angelo