Embodiments include techniques for automatically restarting a voltage foldback circuit, the techniques include operating a circuit, and detecting a condition of the circuit. The techniques also include performing a foldback operation based at least in part on the condition of the circuit, subsequently detecting the condition of the circuit. The techniques include initiating a timer of the circuit based at least in part on the subsequent detection of the circuit, and returning the circuit to normal operation based on the timer.

A method of increasing a multiplication ratio of a charge pump, the multiplication ratio defining a relationship between an output voltage of the charge pump and an input voltage of the charge pump, comprising: analyzing a first efficiency of the charge pump when the multiplication ratio is at a first ratio, calculating a second efficiency of the charge pump when the multiplication ratio is a second ratio lesser than the first ratio, and based on the first efficiency and the second efficiency, determining at least one of a target output power and a target output voltage at which to change the multiplication ratio from the second ratio to the first ratio.

A dual level current limit apparatus constituted of: an electronically controlled switch coupled between a load and a line voltage; and a control circuitry arranged to alternately: control said electronically controlled switch to limit the magnitude of current flowing therethrough responsive to the difference between a predetermined first function of the current magnitude and a predetermined reference voltage, and control said electronically controlled switch to limit the magnitude of current flowing therethrough responsive to the difference between said first function of the current magnitude and a predetermined second function of the load voltage.

A method and apparatuses for power regulation using an extended current limit are disclosed. The power regulator detects an occurrence of an output current of the regulator exceeding a first current limit, triggers an extended current limit timer based on the detected occurrence, regulates the output current according to a second current limit higher than the first current limit based on a duration of the extended current limit timer, and regulates the output current according to the first current limit based on an expiration of the duration of the extended current limit timer.

A dual level current limit apparatus constituted of: an electronically controlled switch coupled between a load and a line voltage; and a control circuitry arranged to alternately: control said electronically controlled switch to limit the magnitude of current flowing therethrough responsive to the difference between a predetermined first function of the current magnitude and a predetermined reference voltage, and control said electronically controlled switch to limit the magnitude of current flowing therethrough responsive to the difference between said first function of the current magnitude and a predetermined second function of the load voltage.

A method of increasing a multiplication ratio of a charge pump, the multiplication ratio defining a relationship between an output voltage of the charge pump and an input voltage of the charge pump, comprising: analyzing a first efficiency of the charge pump when the multiplication ratio is at a first ratio, calculating a second efficiency of the charge pump when the multiplication ratio is a second ratio lesser than the first ratio, and based on the first efficiency and the second efficiency, determining at least one of a target output power and a target output voltage at which to change the multiplication ratio from the second ratio to the first ratio.

A constant voltage generator circuit includes a first amplifier circuit that drives a transistor controlling an output current based on a reference voltage; a second amplifier circuit that drives the transistor based on the reference voltage from the power source; a protection circuit that limit an output current flowing through the load from the transistor; and a control circuit that controls operation of the second amplifier circuit. The control circuit controls the second amplifier circuit to operate or not to operate based on a relationship between the output current and predetermined first or second threshold. The second amplifier circuit further includes a first operation voltage potential fixing circuit that fixes an operation voltage potential of an internal node of the second amplifier circuit during non-operation thereof.

An overcurrent protection circuit for use in a power supply system to control switching on of the circuit. The circuit is connected between a voltage source and a load. A current sensing resistor senses the current flowing to the load and a pair of thermally coupled transistor switches detect a predetermined voltage drop across the current sensing resistor when the current in the current sensing resistor exceeds a first threshold. A control switch limits the power delivered to the load from the voltage source when the pair of transistor switches detecting the predetermined voltage drop.

A power converter system configured to supply DC power to a load is provided, comprising a power converter device responsive to an AC input voltage and configured to provide an output DC voltage; an output voltage loop controller in operable communication with the power converter; an output current loop controller in operable communication with the power converter; an output power loop controller in operable communication with the power converter; and a foldback controller in operable communication with the power converter. The output voltage loop controller, the output current loop controller, the output power loop controller, and the foldback controller together control the power converter to provide a multi-sloped output characteristic, including constant output voltage in voltage mode, increased output current in a first constant power mode, decreased output current and voltage in a foldback mode, and increasing output current and decreasing output voltage in a second constant power mode.

A constant voltage generator circuit includes a first amplifier circuit that drives a transistor controlling an output current based on a reference voltage; a second amplifier circuit that drives the transistor based on the reference voltage from the power source; a protection circuit that limit an output current flowing through the load from the transistor; and a control circuit that controls operation of the second amplifier circuit. The control circuit controls the second amplifier circuit to operate or not to operate based on a relationship between the output current and predetermined first or second threshold. The second amplifier circuit further includes a first operation voltage potential fixing circuit that fixes an operation voltage potential of an internal node of the second amplifier circuit during non-operation thereof.