Abstract: A Buck constant voltage driver and an application circuit thereof, are disclosed. In the Buck constant voltage driver, the peripheral structure is remained unchanged for possessing the advantages of low cost and simplicity of the prior art. Meanwhile, in order to compensate the difference of output voltage caused by the change of the forward voltage drop under different output currents, an output voltage compensation module is added to the Buck constant voltage driver. The output voltage compensation module is operable to acquire an output current information based on the sampling voltage on the sampling resistor, and to compensate the preset first reference voltage according to the output current information, thus maintaining the output voltage of the Buck constant voltage driver constant, under different output current conditions.

Abstract: A chip, a self-calibration circuit and method for chip parameter offset upon power-up are disclosed. The circuit includes a counting circuit, a calibration data latch circuit, a calibration data selection circuit and a parameter calibration circuit. The counting circuit outputs a sequentially scanned counting signal when receiving a valid enabling signal. The calibration data latch circuit latches the counting signal when receiving a valid latch signal. The calibration data selection circuit selects the counting signal latched by the calibration data latch circuit as a calibration signal when receiving the valid latch signal, otherwise selects the counting signal currently outputted as the calibration signal. The parameter calibration circuit implements a parameter calibration based on the calibration signal in a calibration mode, while outputs the valid latch signal when the parameter calibration satisfies a preset requirement.

Abstract: Disclosed are a Darlington transistor drive circuit, a Darlington transistor drive method implemented based on such Darlington transistor drive circuit, and a constant current switching power supply including such Darlington transistor drive circuit. The Darlington transistor drive circuit includes a drive current circuit, two switch units, and a drive control circuit used for controlling the two switch units to be switched off during the switching-on cycle of the Darlington transistor and to be switched on during a switching-off cycle of the Darlington transistor, and for changing an equivalent resistance of the two switch units at different stages during the switching- off cycle of the Darlington transistor. The switching-off time delay of the Darlington transistor is greatly reduced while achieving the EMI optimization. In additional, the switch loss of Darlington transistor is small when it is switched off, and the efficiency is improved.