Patent ID: 6342791
Filing Date: 2002-01-29
Classification: G01R

Abstract:
A diode defect detecting device used in a controller in which an inverter converts a direct current into an alternate current and supplies the alternate current to a primary side of a transformer, and a rectifying circuit having a plurality of diodes connected to a secondary side of said transformer rectifies an alternate current induced on the secondary side into a direct current and supplies the direct current to a load, comprising:a current detector for detecting a primary current of said transformer; a comparator for comparing the detection current detected by said current detector with a current reference and outputting a reset signal if the detection current is larger than the current reference; an oscillator for generating a clock signal; a flip-flop circuit for receiving a set signal based on a front and an end edge of the clock signal generated by said oscillator and receiving the output reset signal from said comparator; a polarity changing circuit for outputting a polarity changing signal for changing polarities of said plurality of diodes on the basis of the output clock signal from said flip-flop circuit; and a determination circuit for calculating, in order to detect malfunctions of said plurality of diodes, an impedance change on the secondary side viewed from the primary side of said transformer based on a pulse width of each polarity of output clock signal from said flip-flop circuit.