Patent ID: 8866515

Claim:
A drive unit for driving a voltage-driven element, the drive unit comprising: a switching circuit; and an abnormal signal generating circuit, wherein the switching circuit is configured to be connected to an external time generating circuit, and is configured to switch a driving condition relating to a driving voltage of the voltage-driven element during a transitional period between a driving state and a non-driving state of the voltage-driven element based on a measurement time which is measured by using the time generating circuit, and the abnormal signal generating circuit is configured to generate an abnormal signal when an accurate measurement of the time using the time generating circuit is not executed, the switching circuit is configured to measure the time after the transitional period starts by using the time generating circuit, and is configured to switch the driving condition when the measurement time reaches a first predetermined time, the switching circuit includes a reference current source and a comparator, the reference current source is configured to be connected to a capacitor disposed in the time generating circuit, and is configured to provide a reference current to the capacitor after the transitional period starts, and the comparator is configured to be connected to the capacitor of the time generating circuit, and is configured to determine that the measurement time reached the first predetermined time when a voltage on a connection line which is connected to the capacitor reaches a first threshold voltage.