Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.