Abstract: A phase-locked loop (PLL)-based power converter is disclosed. A power converter includes a switch circuit having a switch node coupled to a regulated power supply node via an inductor and configured to source a supply current to the regulated power supply node using one or more control signals. A control circuit performs a phase-frequency comparison of a reference clock signal and a switching frequency of the switch circuit and generate a control voltage using results of the phase-frequency comparison. The control circuit further generates a control current using the control voltage, a voltage of the regulated power supply node, and a duty cycle of the switch circuit, and a demand current using the voltage level of the regulated power supply node and a reference voltage. Using the demand current, the control current, and a sensed version of the supply current, the control circuit generates the one or more control signals.

Abstract: A power converter circuit included in a computer system may charge and discharge a switch node coupled to a regulated power supply node via an inductor. The power converter circuit may generate a reference clock signal using a system clock signal and a voltage level of the switch node. The reference clock signal may be used to initiate a charge cycle, whose duration may be based on generated ramp signals.

Abstract: A power converter circuit included in a computer system may charge and discharge a switch node coupled to a regulated power supply node via an inductor. The power converter circuit may generate a reference clock signal using a system clock signal and a voltage level of the switch node. The reference clock signal may be used to initiate a charge cycle, whose duration may be based on generated ramp signals.

Abstract: A power converter circuit included in a computer system may charge and discharge a switch node coupled to a regulated power supply node via an inductor. During a charge cycle, the power converter circuit may generate a reference ramp signal that has an initial voltage level greater than that of the switch node. The power converter may also generate a sense ramp signal using the voltage level of the switch node, and halt the charge cycle using results of a comparison of the respective voltage levels of the reference ramp signal and the sense ramp signal.

Abstract: This application relates to a lighting system comprising a plurality of light emitting diode, LED, circuits, and a power source for providing a drive voltage to the plurality of LED circuits. For each LED circuit, the lighting system comprises a first variable resistance element connected between the respective LED circuit and ground, and a first feedback circuit configured to control a voltage at a first node between the respective LED circuit and the respective first variable resistance element to a first voltage. The lighting system further comprises a current source and a second variable resistance element connected between the current source and ground, wherein each first variable resistance element is configured to attain a resistance value depending on a resistance value attained by the second variable resistance element.

Abstract: This application relates to a lighting system comprising a plurality of light emitting diode, LED, circuits, and a power source for providing a drive voltage to the plurality of LED circuits. For each LED circuit, the lighting system comprises a first variable resistance element connected between the respective LED circuit and ground, and a first feedback circuit configured to control a voltage at a first node between the respective LED circuit and the respective first variable resistance element to a first voltage. The lighting system further comprises a current source and a second variable resistance element connected between the current source and ground, wherein each first variable resistance element is configured to attain a resistance value depending on a resistance value attained by the second variable resistance element.

Abstract: A current mode control buck-boost converter with improved performance utilizes separate buck and boost pulses. The buck-boost converter utilizes a buck/boost decision method with continuous control voltage for buck and boost mode, therefore eliminating transients in the control loop between operation modes and preventing voltage overshoots. If switching in Boost mode and the buck duty cycle is smaller than a set duty cycle, then in the next cycle Buck mode switching will occur. It is possible to track a Buck comparator output and the related duty cycle during Boost mode operation. Thus a mode change decision will only be dependent on a single input. A control loop will incorporate a single loop filter and error amplifier, wherein control voltages for Buck comparator and Boost comparator will be related.

Abstract: This application relates to a lighting system comprising a plurality of light emitting diode, LED, circuits, and a power source for providing a drive voltage to the plurality of LED circuits. For each LED circuit, the lighting system comprises a first variable resistance element connected between the respective LED circuit and ground, and a first feedback circuit configured to control a voltage at a first node between the respective LED circuit and the respective first variable resistance element to a first voltage. The lighting system further comprises a current source and a second variable resistance element connected between the current source and ground, wherein each first variable resistance element is configured to attain a resistance value depending on a resistance value attained by the second variable resistance element.

Abstract: A measurement circuit for providing the maximum and/or minimum voltage of a time-variant electrical input signal is presented. The measurement circuit contains a voltage reference unit to provide voltage reference signals and a comparator unit comprising multiple comparators. Each comparator receiving the electrical input signal at a first comparator input and a different voltage reference signal from the voltage reference unit at its second comparator input. The comparator unit provides comparator output signals based on said electrical input signal and said voltage reference signals. A logic unit receives the comparator output signals and provides a voltage output signal indicative of the maximum and/or minimum voltage of the electrical input signal based on the comparator output signals. The logic unit provides adaptation information to the voltage reference entity. The is adaptation information is dependent on the comparator output signals.

Abstract: This application relates to a lighting system comprising a plurality of light emitting diode, LED, circuits, and a power source for providing a drive voltage to the plurality of LED circuits. For each LED circuit, the lighting system comprises a first variable resistance element connected between the respective LED circuit and ground, and a first feedback circuit configured to control a voltage at a first node between the respective LED circuit and the respective first variable resistance element to a first voltage. The lighting system further comprises a current source and a second variable resistance element connected between the current source and ground, wherein each first variable resistance element is configured to attain a resistance value depending on a resistance value attained by the second variable resistance element.

Abstract: A current mode control buck-boost converter with improved performance utilizes separate buck and boost pulses. The buck-boost converter utilizes a buck/boost decision method with continuous control voltage for buck and boost mode, therefore eliminating transients in the control loop between operation modes and preventing voltage overshoots. If switching in Boost mode and the buck duty cycle is smaller than a set duty cycle, then in the next cycle Buck mode switching will occur. It is possible to track a Buck comparator output and the related duty cycle during Boost mode operation. Thus a mode change decision will only be dependent on a single input. A control loop will incorporate a single loop filter and error amplifier, wherein control voltages for Buck comparator and Boost comparator will be related.

Abstract: This invention relates to control circuits for LED systems with a feedback loop to regulate a drive voltage. A controller for the system is proposed comprising a plurality of LED circuits and a controllable power source. The controller comprises a control unit configured to cause regulation of the drive voltage based on a determination of a plurality of feedback voltages and a fault condition detecting means. At least one of the LED circuits is determined as having a fault condition if the respective feedback voltage is below a fault threshold. In response to a detected fault condition, a test voltage is applied to a cathode of the fault circuit to confirm the presence of a fault condition.

Abstract: This invention relates to control circuits for LED systems with a feedback loop to regulate a drive voltage. A controller for the system is proposed comprising a plurality of LED circuits and a controllable power source. The controller comprises a control unit configured to cause regulation of the drive voltage based on a determination of a plurality of feedback voltages and a fault condition detecting means. At least one of the LED circuits is determined as having a fault condition if the respective feedback voltage is below a fault threshold. In response to a detected fault condition, a test voltage is applied to a cathode of the fault circuit to confirm the presence of a fault condition.