Electronic control device

An electronic control device, comprising:

• a first switching element for driving a load, connected in series with the load between a power source and ground;
• a second switching element to be turned on/off for taking ON/OFF control of the first switching element, connected to the control terminal of the first switching element;
• a pulse generator for supplying a drive signal to the second switching element to take ON/OFF control thereof;
• and
• a control circuit including a trigger circuit which comprises a series connection of a first resistor and a capacitor and is connected between output terminals of the pulse generator, in which a connecting point of the first resistor with the capacitor is connected to the control terminal of the second switching element, and a latch circuit which comprises a series connection of a diode and a second resistor and is connected between a first junction that is a connecting point of the load with the first switching element and a connecting point of the capacitor to the control terminal of the second switching element, in which the diode is connected in forward direction with respect to the first switching element;
• wherein, when the pulse generator outputs a drive signal, the control circuit turns on through the trigger circuit the second switching element for a predetermined time, thereby also turning on the first switching element so as to drive the load, and in addition, holds the second switching element in an ON state by supplying an operation current to the control terminal of the second switching element, through the diode of the latch circuit by a voltage generated at the first junction when the first switching elements is turned on, and
• wherein, when the pulse generator stops outputting the drive signal, the control circuit turns off both of the first switching element and the second switching element;
• meanwhile if the load is short-circuited when the pulse generator is outputting the drive signal, the control circuit turns off the second switching element by shutting off supplying the operation current to the control terminal of the second switching element, through the diode of the latch circuit by the voltage generated at the first junction, thereby also turning off the first switching element.