| 摘要 |
PURPOSE:To regularly detect the fail of a load driving control system at a high precision by using a driving current with dither having the dither amplitude increased at the time of a reduction in power source voltage as a driving current, and detecting the fail of the load driving control system by monitoring the presence of the driving current with dither. CONSTITUTION:A dither current setting means (d) sets a dither current to have an amplitude and frequency not followed by a load (b) when a power source voltage to be supplied to a load driving control system is normal, and to increase the dither amplitude when the power source voltage is less than a determined value. At the time of detecting a fail such as the breaking and short-circuit of a harness, a driving current with dither is inputted from the harness connected to the load (b) in a load driving control system fail detecting means (e), and the fail is detected by monitoring the presence of the dither. As this driving current with dither is a current obtained by superposing dither currents in regardless of the current value of the driving current, the fail can be detected without any time limit even if the driving current value is zero. |
