Load control apparatus and method for processing diagnosis signal for the same

A method for processsing a diagnosis signal for a load control apparatus, which is configured to output a pulse width modulation signal to a switching element, which is connected between a power supply and ground in series with a load, according to an external drive instruction signal to control the load, the method comprising:

• generating an abnormal increase detection signal when detecting an abnormal increase in applied voltage, which is applied to the load, relative to a target voltage;
• generating an abnormal decrease detection signal when detecting an abnormal decrease in the applied voltage relative to the target voltage;
• generating a normally operating signal according to an output of the pulse width modulation signal when the load normally operates;
• generating a combined signal by combining the abnormal increase detection signal, the abnormal decrease detection signal, and the normally operating signal;
• and
• outputting the combined signal via a common signal output terminal such that the abnormal increase detection signal, the abnormal decrease detection signal, and the normally operating signal are distinguishable from each other.

A load control apparatus configured to output a pulse width modulation signal to a switching element, which is connected between a power supply and ground in series with a load, and configured to control the switching element according to an external drive instruction signal, the load control apparatus comprising:

• means for outputting an abnormal increase detection signal when detecting an abnormal increase in applied voltage, which is applied to the load, relative to a target voltage;
• means for outputting an abnormal decrease detection signal when detecting an abnormal decrease in the applied voltage relative to the target voltage;
• means for outputting a normally operating signal according to an output of the pulse width modulation signal when the load normally operates;
• means for generating a combined signal by combining the abnormal increase detection signal, the abnormal decrease detection signal, and the normally operating signal and outputting the combined signal via a common signal output terminal;
• and
• means for generating the pulse width modulation signal based on the drive instruction signal and the applied voltage and configured to output the pulse width modulation signal,
• wherein the means for outputting an abnormal increase detection signal detects the abnormal increase when a value, which is calculated by subtracting the drive instruction signal from the applied voltage, becomes greater than a threshold,
• the means for outputting an abnormal decrease detection signal detects the abnormal decrease when a value, which is calculated by subtracting the applied voltage from the drive instruction signal, becomes greater than a threshold,
• the abnormal increase detection signal and the abnormal decrease detection signal respectively indicate a high level and a low level,
• the means for outputting an abnormal increase detection signal and the means for outputting an abnormal decrease detection signal are configured to refer to a reference signal, which is one of the drive instruction signal and a reference voltage, which relates to a voltage of the power supply,
• the means for generating the pulse width modulation signal is configured to compare a signal-instruction level of the pulse width modulation signal with a 100%-instruction level, which corresponds to the pulse width modulation signal at substantially 100% duty, and
• the means for generating the pulse width modulation signal is configured to replace the reference signal from the drive instruction signal to the reference voltage when detecting that the signal-instruction level is greater than the 100%-instruction level.

A load control apparatus configured to output a pulse width modulation signal to a switching element, which is connected between a power supply and ground in series with a load, and configured to control the switching element according to an external drive instruction signal, the load control apparatus comprising:

• means for outputting an abnormal increase detection signal when detecting an abnormal increase in applied voltage, which is applied to the load, relative to target voltage;
• means for outputting an abnormal decrease detection signal when detecting an abnormal decrease in the applied voltage relative to the target voltage;
• means for outputting a normally operating signal according to an output of the pulse width modulation signal when the load normally operates;
• and
• means for
• generating a combined signal by combining the abnormal increase detection signal received from the means for outputting an abnormal increase detection signal, the abnormal decrease detection signal received from the means for outputting an abnormal decrease detection signal, and the normally operating signal received from the means for outputting a normally operating signal such that the abnormal increase detection signal, the abnormal decrease detection signal, and the normally operating signal are distinguishable from each other, and
• outputting the combined signal via a common signal output terminal;
• and
• means for monitoring a state of the combined signal outputted from the common signal output terminal to detect the abnormal increase in applied voltage, the abnormal decrease in the applied voltage, and normal operation of the load,
• wherein the abnormal increase detection signal indicates the abnormal increase in applied voltage, the abnormal decrease detection signal indicates the abnormal decrease in the applied voltage, and the normally operating signal indicates the normal operation of the load.