| 摘要 |
PURPOSE:To facilitate detection of the magnitude of a load current by a method that, switching devices are turned OFF from the ON state to cut off the current supply to the load when the output of an amplifier exceeds a predetermined level. CONSTITUTION:If switching devices 21 and 22 are turned ON from an OFF state, a current is supplied to a load 1 from a power supply 11 through a resistor 24 and the switching devices 21 and 22. At the same time, the current applied to a resistor 24 is shunted by electric resistance elements 45 and 46 and made to flow into a ground. If the load 1 is locked to stop, the current applied to the load 1 is increased and, accordingly, the current applied to the electric resistance elements 45 and 46 is reduced. If the output level of an amplifier 31 exceeds a predetermined level as a result, a comparator 32 generates an output and the switching devices 21 and 22 are turned OFF from the ON state by the output of the comparator 32 and the current supply to the load 1 is cut off. With this constitution, even if the voltage level of the power supply 11 fluctuates, the magnitude of the current applied to the load 1 can be detected without fail. |
