Intersil Americas Inc.

Robert L Lyle, Jr

Steven Patrick Laur

Zaki Moussaoui

Barry Harvey

Brian Ben North

Dong Zheng

Eric Magne Solie

Lawrence Pearce

A Buck switching regulator includes first Buck switching regulator circuitry is operable to generate a first output voltage from an input voltage and operable to generate a first sensed voltage having a value that is proportional to an output current being provided by the first Buck switching regulator circuitry. The first Buck switching regulator circuitry receives an input current and operates at a first duty cycle determined by a duty cycle signal. Input current sensing circuitry includes second Buck switching regulator circuitry coupled to the first Buck regulator switching circuitry to receive the duty cycle signal and to receive the first sensed voltage as an input voltage to the second Buck switching regulator circuitry. The second Buck switching regulator circuitry is operable responsive to the duty cycle signal to generate a second output voltage from the first sensed voltage. The second output voltage has a value that is proportional to the input current being supplied to the first Buck switching regulator circuitry. Such a Buck switching regulator can be utilized in a variety of different types of electronic systems, such as laptop computer systems, and can also be used in charging systems in laptop computer and other types of electronic systems.

Switching regulator input current sensing circuit, system, and method

A double-ended, DC-AC converter supplies AC power to a load, such as a cold cathode fluorescent lamp used to back-light a liquid crystal display. First and second converter stages generate respective first and second sinusoidal voltages having the same frequency and amplitude, but having a controlled phase difference therebetween. By employing a voltage controlled delay circuit to control the phase difference between the first and second sinusoidal voltages, the converter is able to vary the amplitude of the composite voltage differential produced across the opposite ends of the load. The converter may be either voltage fed or current fed.

Phase shift modulation-based control of amplitude of AC voltage output produced by double-ended DC-AC converter circuitry for powering high voltage load such as cold cathode fluorescent lamp

A modulator for use with a voltage regulator includes an input for receiving an input voltage, an output for providing a periodic triangular wave form and at least one input for receiving an indication that the voltage regulator is in a discontinuous current mode of operation. The circuitry within the modulator generates the periodic triangular wave form responsive to the input voltage and the indication that the voltage regulator is in the discontinuous current mode of operation. The circuitry further continuously increases a period of the periodic triangular wave form responsive to a decreased load in a discontinuous current mode of operation of the voltage regulator.

Modulator with linear period stretching capability

An apparatus and method for controlling the operation of a utility device, such as a cold cathode fluorescent lamp that is powered in accordance with a pulse width modulation (PWM) signal, includes an analog sensor which monitors the utility device to derive an output signal representative of the PWM signal. An integrating analog-to-digital converter (ADC), which is coupled to the sensor and has its operation synchronized with an integral multiple of the period of the PWM signal, produces an output representative of an average of the output of the utility device.

Digitally synchronized integrator for noise rejection in system using PWM dimming signals to control brightness of cold cathode fluorescent lamp for backlighting liquid crystal display

An AC power supply system modulates a high frequency switching signal with a pulse width modulation (PWM) signal to produce a composite signal. The duty cycle of the PWM component of the composite signal is used to control the brightness of a cold cathode fluorescent lamp for backlighting a liquid crystal display.

Apparatus and method of employing combined switching and PWM dimming signals to control brightness of cold cathode fluorescent lamps used to backlight liquid crystal displays

A phase-modulated, double-ended, full-bridge topology-based DC-AC converter supplies AC power to a load, such as a cold cathode fluorescent lamp used to back-light a liquid crystal display. First and second converter stages generate respective first and second sinusoidal voltages having the same frequency and amplitude, but having a controlled phase difference therebetween. By employing a voltage controlled delay circuit to control the phase difference between the first and second sinusoidal voltages, the converter is able to vary the amplitude of the composite voltage differential produced across the opposite ends of the load.

DC-AC converter having phase-modulated, double-ended, full-bridge topology for powering high voltage load such as cold cathode fluorescent lamp

A phase-modulated, double-ended, half-bridge topology-based DC-AC converter supplies AC power to a load, such as a cold cathode fluorescent lamp used to back-light a liquid crystal display. First and second converter stages generate respective first and second sinusoidal voltages having the same frequency and amplitude, but having a controlled phase difference therebetween. By employing a voltage controlled delay circuit to control the phase difference between the first and second sinusoidal voltages, the converter is able to vary the amplitude of the composite voltage differential produced across the opposite ends of the load.

DC-AC converter having phase-modulated, double-ended, half-bridge topology for powering high voltage load such as cold cathode fluorescent lamp

Digitally synchronized integrator for noise rejection in system using PWM dimming signals to control brightness of light source

In order to minimize switching-induced electromagnetic interference in a power supply switching circuit of the type used to control the AC power for multiple high voltage devices, such as cold cathode fluorescent lamps employed for backlighting a large scale liquid crystal display, the gating signals that are used to switch lamp-driving inverter circuits ON and OFF are staggered, or slightly offset in time, so that no two switching devices will be switched at the same time. By slightly offset in time is meant that the time differential between any pair of switching signals is relatively small compared to the period of the switching signal frequency. This has the effect of spreading out and thereby diminishing the magnitude of the spectral content of both capacitively and inductively coupled transients that are produced at switching times of the inverter circuits.

Staggering switching signals for multiple cold cathode fluorescent lamp backlighting system to reduce electromagnetic interference

A distributed controller and DC voltage switch-driver system supplies AC power to a cold cathode fluorescent lamp of the type used to backlight a liquid crystal display. The system includes a local controller and lamp operation-monitoring subsystem, which generates two pairs of low voltage drive signals. These drive signals are distributed over low voltage wires to respective pairs of step-up transformer-driving switches installed at opposite ends of the lamp. The high voltage AC outputs of the two transformers have the same frequency, but opposite phase, to reduce the voltage ratings of the components that are installed at the opposite ends of the lamp. The use of low voltage connections from the local controller to driver circuitry at the far end of the lamp serves to reduce the cost of the components, and results in lower emitted noise and lower energy lost to capacitive coupling.

Growing community of inventors

Raleigh, NC, United States of America

Robert L Lyle, Jr