Patent ID: 6424130
Filing Date: 2002-07-23
Classification: H02M

Abstract:
A voltage converter comprising: an input terminal for receiving a DC input voltage; an output terminal for outputting a DC regulated output voltage; a regulating circuit for detecting a level of the regulated output voltage and controlling the level thereof so that the regulated output voltage is maintained within a predetermined voltage range, the regulating circuit comprising a DC-DC converter circuit having a switching element connected to the output terminal, a reference voltage source for producing a reference voltage, a chopping wave generating circuit for producing a chopping wave, a voltage dividing circuit having first and second resistors for dividing the regulated output voltage and producing a first divided output voltage at a node between the first and second resistors, a smoothing circuit for smoothing an output of the switching element, an error amplifier for receiving the divided output voltage and the reference voltage and producing an error signal, and a first comparator for comparing the error signal and the chopping wave and producing a comparison output for driving the switching element; and a voltage detecting circuit for detecting when the regulated output voltage has increased above the predetermined voltage range and preventing the regulated output voltage from further increasing so that the regulated output voltage rapidly returns to a value within the predetermined voltage range; wherein the voltage dividing circuit further comprises a third resistor connected to the second resistor so that a second divided output voltage is produced at a node between the second and third resistors; and wherein the voltage detecting circuit comprises the third resistor, a second comparator for comparing the reference voltage and the second divided output voltage, and a logic circuit for performing a logical operation on an output of the first comparator and the second comparator and producing a signal for controlling the conduction state of the switching element.