| 摘要 |
PROBLEM TO BE SOLVED: To provide a load drive circuit capable of preventing an output power fault state from being detected erroneously.SOLUTION: The load drive circuit comprises: a switching element Q1; a first comparator CP1 which compares a first reference voltage V1 lower than a voltage E inputted to a power supply terminal Vcc with a voltage of an output terminal OUT and detects a load open state where the switching element Q1 is being turned off and a load 20 is not being connected to the output terminal; a second comparator CP2 which compares a reference voltage V2 lower than the voltage E and higher than a clamp voltage with the voltage of the output terminal OUT and detects the output power failure state; a clamp circuit 14 which clamps the voltage of the output terminal to the clamp voltage higher than the first reference voltage and lower than the voltage E in the load open state; a capacitor C1; a boot strap circuit 10 which supplies a charge current to an amp terminal by a constant voltage generated based on the voltage E of a power source; and a clamp voltage rise suppression circuit 16 which suppresses rising of the clamp voltage of the clamp circuit if the first comparator detects the load open state.SELECTED DRAWING: Figure 1 |
