| 摘要 |
A load-driving circuit supplies electric current to a load, such as a resistor of an airbag squib. The load-driving circuit includes high side and low side current control circuits, both connected in series. Each current control circuit is composed of a driving transistor, a resistor and a current mirror circuit for controlling operation of the driving transistor. The components in the load-driving circuit are positioned in an integrated circuit chip to generate different temperature gradients among the components. For example, the low side resistor is positioned close to the high side driving transistor, so that the low side resistor is heated by the high side driving transistor controlled under a constant current control. As the low side resistor is heated, the high side driving transistor is switched from the constant current control to a full-on control. In this manner, controls of both driving transistors are automatically switched thereby to avoid overheating of one of the driving transistors.
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