| 摘要 |
<p>A circuit protects from overcurrent conditions and detects an open electrical load. A microprocessor (10) has at least one microprocessor terminal that is configurable as an output for generating a command signal to an electrical load and as an input for monitoring the condition of the electrical load. A first transistor (50) is operatively connected to the microprocessor terminal and has an output to be connected to the electrical load. The first transistor has ON and OFF states. A second transistor (60) is powered from a power supply and is connected to the first transistor and the microprocessor terminal. The second transistor is operative to generate an output logic signal back to the microprocessor and to latch the first transistor into one of either ON or OFF states under normal load conditions responsive to the receipt of a command signal from the microprocessor, and to maintain the first transistor in an OFF state upon an abnormal overcurrent condition through the first transistor. The second transistor is also operative to maintain an open load logic signal to the microprocessor after repeated attempts to switch the first transistor into an OFF state. <IMAGE></p> |
