| 摘要 |
PROBLEM TO BE SOLVED: To continue PWM control even if a load has a power fault or a ground fault.SOLUTION: A PWM control device has a common current detection circuit for detecting a total value I of load currents of respective drive circuits. Current estimation means is also provided for calculating a load current Ito be otherwise detected in a drive circuit with a power fault or ground fault detected, from a load current Iin a drive circuit with no power fault or ground fault detected, on the basis of an equation: I=I-I. On the basis of the value of Icalculated by the current estimation means, a duty ratio of a PWM signal to be input into a driving switching element of the drive circuit with the power fault or ground fault detected is decided in continuing PWM control. |
