SWITCHING VOLTAGE REGULATOR

摘要

A switching voltage regulator circuit of a simple design exhibiting high efficiency and reducing manufacturing costs comprises a switching device including a N-channel MOSFET receiving the input voltage signal and having an output being coupled to an output filter generating the regulated output voltage signal. The preferred embodiment makes use of four comparator amplifiers allowing the use of a single package integrated circuit. The embodiment comprises a first voltage comparator amplifier sensing current drawn by the load to generate a current error signal whenever the current exceeds a predetermined current limit value. The second voltage comparator amplifier receives the regulated output voltage signal and the current error signal for comparing thereof to a reference voltage to generate a voltage error signal. There is provided a Pulse Width Modulator switching control device receiving the voltage error signal to generate a control signal for the switching device. The switching control device comprises the third voltage comparator amplifier arranged in an oscillator configuration to generate a triangular ramp signal and the fourth voltage comparator amplifier receiving the voltage error signal for comparing thereof to said triangular ramp signal to generate a pulse-width-modulated output signal. A driving stage is provided for generating the control signal. The switching voltage regulator circuit can be adapted to provide a back-up battery charging device with battery testing feature, with the adding of a microcontroller having a sensing input being coupled to the battery and an output being coupled to the input of the voltage comparator amplifier. The regulator can be changed from a battery charging mode into a battery test mode allowing the controller to compare sensed voltage supplied by the battery to a predetermined minimum voltage threshold and to generate an alarm signal whenever the sensed battery voltage is lower than the minimum voltage threshold.