Patent ID: 6239585
Filing Date: 2001-05-29
Classification: H02M

Abstract:
A self-oscillating switched mode, DC-to-DC converter for receiving an input voltage and producing an output voltage, comprising:a first switch connected between a first input terminal and a first output terminal through a current sensing element, the first input terminal being connected to an input voltage, the first output terminal producing an output voltage, the first switch being either in an OFF or an ON state and when in its ON state conducting an essentially constant current;a second switch connected between the first input terminal and the first output terminal, the second switch alternating between a fully ON and a fully OFF state, the second switch having a turn-on threshold depending on a voltage drop between the first switch and the second switch, the state of the second switch depending on the voltage drop between the first switch and the second switch with respect to the turn-on threshold, the second switch operating opposite in phase to the first switch;a third switch connected between the first input terminal and the first output terminal, the third switch operating opposite in phase to the second switch, having a state controlled by the second switch;a fourth switch connected between the first input terminal and the first output terminal, the fourth switch operating in phase with the third switch, having a state controlled by the third switch;a second input terminal connected to a second output terminal, the second input terminal and the second output terminal being further connected to a reference voltage;current storage and sensing means receiving current from the fourth switch and producing a voltage drop between the first switch and the second switch, the voltage drop depending on the level of stored current, the voltage drop serving to control the state of the second switch; andhysteresis means for controlling the turn-on threshold of the second switch.