Patent ID: 7525318

Claim:
A load abnormality detecting system, comprising: a voltage generator for generating a specified voltage (Vs) in accordance with an amount of a current (IL) flowing to a load present outside of the system, a judging device for judging whether or not the load has any abnormality by comparing a signal corresponding to the specified voltage (Vs) and a burnout reference value (T 1 ) and/or a short-circuit reference value (T 2 ), and a selector for causing either one of the burnout reference value (T 1 ) and the short-circuit reference value (T 2 ) to be selectively inputted to one input portion of the judging device, wherein: the voltage generator includes a first resistor (R 1 ) disposed between the other input portion of the judging device and a reference potential, and a second resistor (R 2 ) connected in parallel with the first resistor (R 1 ) between the other input portion of the judging device and the reference potential, and the selector causes the burnout reference value (T 1 ) to be inputted to the one input portion of the judging device and controls the voltage generator so as not to form a current path via the second resistor (R 2 ) in the case of checking the burnout of the load while causing the short-circuit reference value (T 2 ) to be inputted to the one input portion of the judging device and controlling the voltage generator so as to form the current path via the second resistor (R 2 ) in the case of checking the short circuit of the load, wherein specified voltage Vs is given by Vs=Is×{r 1· r 2/( r 1+ r 2)} where Is is a signal current corresponding to the current flowing to the load, r 1 is the resistance value of the first resistor (R 1 ), and r 2 is the resistance value of the second resistor (R 2 ).