| 摘要 |
PROBLEM TO BE SOLVED: To provide an electric load control circuit for vehicle, which drives a field effect transistor for driving a coil by pulse width modulation(PWM) control and which is able to protect a load, when a power supply is reversely connected and increase the current efficiency with the increase in the number of components being suppressed. SOLUTION: This circuit is constituted of a coil 3 inserted between a power supply 1 and the ground 2a, a field effect transistor 5 which is inserted between the coil 3 and the ground 2a and is provided in parallel with a parasitic diode 4, which allows current to flow only in one direction from the ground 2a to the power supply 1, an microprocessor unit(MPU) for driving the field effect transistor 5 by PWM control, a flywheel diode 6 which is inserted between a point between the downstream side of the coil 3 and the field effect transistor 5 and the upstream side of the coil 3 and which allows current to flow only in one direction from the downstream side to the upstream side of the coil 3, and a reverse connection preventing transistor 7 which is inserted between the flywheel diode 6 and the power supply 1 and is operated by the difference in voltage between the ground 2b and the flywheel diode 6. |
