Abstract: Provided is a current supply for providing a charge current to a load. The current supply includes: a driving transistor, providing the charge current to the load; a sensing transistor, limiting the charge current; a pulling low transistor, pulling low a controlling node which controls the driving transistor and the sensing transistor; a constant voltage controller, pulling up the controlling node, controlling the conduction state of the driving transistor and accordingly maintaining the voltage across the load at the first reference voltage, when a voltage across the load rises up and comes close to a first reference voltage; and a constant current controller, controlling the controlling node and the pulling low transistor to limit the charge current to be constantly provided to the load, when the voltage across the load drops much lower than the first reference voltage.

Abstract: A high efficiency control circuit for operating a switching regulator is provided. The switching regulator can regulate an output voltage no matter the input voltage is higher, lower, or close to the output voltage. The switching regulator has first, second, third and fourth switches. The control circuit can operate the switching regulator in buck mode, boost mode, or buck-boost mode. In a buck-boost mode, the control logic drives the four switches in an efficiency sequence for reducing energy consumption during the switch transition, on the other side, resistive loss owing to the energy transfer phase is also minimized. Furthermore, the invention is capable of control duty cycle limitation to fit the consideration of the linearity of the converter.

Abstract: Provided is a current supply for providing a charge current to a load. The current supply includes: a driving transistor, providing the charge current to the load; a sensing transistor, limiting the charge current; a pulling low transistor, pulling low a controlling node which controls the driving transistor and the sensing transistor; a constant voltage controller, pulling up the controlling node, controlling the conduction state of the driving transistor and accordingly maintaining the voltage across the load at the first reference voltage, when a voltage across the load rises up and comes close to a first reference voltage; and a constant current controller, controlling the controlling node and the pulling low transistor to limit the charge current to be constantly provided to the load, when the voltage across the load drops much lower than the first reference voltage.

Abstract: In a voltage reference circuit, a bandgap reference circuit, for generating a bandgap reference voltage and a reference current, includes an operation amplifier, and a first transistor for providing the reference current. Another transistor mirrors the reference current to provide a first current. A compensation controller converts a node voltage from the bandgap reference circuit into a second current and performs current subtraction on the first current and the second current to provide a compensation feedback current to another node of the bandgap reference circuit. So that, second order temperature compensation is performed on the bandgap reference voltage.