Abstract: A system and method for controlling a low-dropout regulator (LDO) is disclosed. The system and method include a charge pump that is controlled to provide a charge pump voltage to power the LDO. The charge pump voltage can be adjusted relative to the LDO's input voltage to ensure efficient operation of the LDO for input voltages over a range. The charge pump is also controlled to limit the maximum charge pump voltage provided to ensure safe operation of the LDO. The system and method also include a under voltage lockout circuit that enables the LDO when it is determined that the charge pump voltage is sufficient to meet multiple criteria. For example, the charge pump voltage may be analyzed to determine if it is above a minimum voltage and if it is also sufficiently higher than the LDO's output voltage.

Abstract: A voltage pre-regulator can receive a variable voltage in a middle voltage range (e.g., dozens of volts) and provide a regulated voltage in a safe operating region of a low voltage device. The use of the voltage pre-regulator can allow circuits to use low voltage devices to perform additional regulation/conversion without fear of damage. The voltage pre-regulator disclosed herein can perform the voltage reduction and regulation functions of pre-regulation with commonly used transistor types because the disclosed circuits and method use a bias circuit. The bias circuit uses positive feedback so that no additional start-up circuitry is required. The positive feedback is controlled by negative feedback so that the pre-regulator is able to provide a regulated voltage that is stable over a range of input voltages and temperatures.

Abstract: A voltage pre-regulator can receive a variable voltage in a middle voltage range (e.g., dozens of volts) and provide a regulated voltage in a safe operating region of a low voltage device. The use of the voltage pre-regulator can allow circuits to use low voltage devices to perform additional regulation/conversion without fear of damage. The voltage pre-regulator disclosed herein can perform the voltage reduction and regulation functions of pre-regulation with commonly used transistor types because the disclosed circuits and method use a bias circuit. The bias circuit uses positive feedback so that no additional start-up circuitry is required. The positive feedback is controlled by negative feedback so that the pre-regulator is able to provide a regulated voltage that is stable over a range of input voltages and temperatures.

Abstract: Some applications require a noise filter to have a very low cutoff frequency. The low cutoff frequency can require the use of a large resistor that is not suitable for integration in an integrated circuit (IC) package. Smaller components can be used to provide a large resistance in a first direction but not in another. In other words, the resistance of these smaller components may be non-reciprocal. A non-reciprocal resistance can affect a response of the noise filter to disruptions at the input or the output. Additionally, these smaller components may not be suitable for low voltage operation. A noise filter is disclosed that provides a high resistance using components that can be included in an integrated circuit package. The noise filter has a reciprocal effective resistance and can utilize technology suitable for low voltage operation.

Abstract: Some applications require a noise filter to have a very low cutoff frequency. The low cutoff frequency can require the use of a large resistor that is not suitable for integration in an integrated circuit (IC) package. Smaller components can be used to provide a large resistance in a first direction but not in another. In other words, the resistance of these smaller components may be non-reciprocal. A non-reciprocal resistance can affect a response of the noise filter to disruptions at the input or the output. Additionally, these smaller components may not be suitable for low voltage operation. A noise filter is disclosed that provides a high resistance using components that can be included in an integrated circuit package. The noise filter has a reciprocal effective resistance and can utilize technology suitable for low voltage operation.

Abstract: A system and method for controlling a low-dropout regulator (LDO) is disclosed. The system and method include a charge pump that is controlled to provide a charge pump voltage to power the LDO. The charge pump voltage can be adjusted relative to the LDO's input voltage to ensure efficient operation of the LDO for input voltages over a range. The charge pump is also controlled to limit the maximum charge pump voltage provided to ensure safe operation of the LDO. The system and method also include a under voltage lockout circuit that enables the LDO when it is determined that the charge pump voltage is sufficient to meet multiple criteria. For example, the charge pump voltage may be analyzed to determine if it is above a minimum voltage and if it is also sufficiently higher than the LDO's output voltage.

Abstract: A system and method for controlling a low-dropout regulator (LDO) is disclosed. The system and method includes a charge pump that is controlled to provide a charge pump voltage to power the LDO. The charge pump voltage can be adjusted relative to the LDO's input voltage to ensure efficient operation of the LDO for input voltages over a range. The charge pump is also controlled to limit the maximum charge pump voltage provided to ensure safe operation of the LDO. The system and method also includes a under voltage lockout circuit that enables the LDO when it is determined that the charge pump voltage is sufficient to meet multiple criteria enable For example, the charge pump voltage may be analyzed to determine if it is above a minimum voltage and also sufficiently higher than the LDO's output voltage.

Abstract: A system and method for controlling a low-dropout regulator (LDO) is disclosed. The system and method includes a charge pump that is controlled to provide a charge pump voltage to power the LDO. The charge pump voltage can be adjusted relative to the LDO's input voltage to ensure efficient operation of the LDO for input voltages over a range. The charge pump is also controlled to limit the maximum charge pump voltage provided to ensure safe operation of the LDO. The system and method also includes a under voltage lockout circuit that enables the LDO when it is determined that the charge pump voltage is sufficient to meet multiple criteria enable For example, the charge pump voltage may be analyzed to determine if it is above a minimum voltage and also sufficiently higher than the LDO's output voltage.

Abstract: Circuits, methods, and system for DC voltage conversion are disclosed. A charge pump circuit is described that includes input switches and output switches that are individually controlled by different clock signals to alternatively couple energy storage capacitors to an input and to an output. The individualized switching control allows for the use of clock signals with no overlapping transitions to improve conversion efficiency. Additionally, the input switches are controlled by clock signals that are level shifted relative to the input voltage. The level shifted switching control also improves efficiency and allows for a range in input voltages to be accommodated for DC voltage conversion.