Semiconductor integrated circuit
AssigneeMitsubishi Denki Kabushiki Kaisha
InventorToshiya Nakano
Life of this patent
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Abstract
A semiconductor integrated circuit is disclosed in which a power MOSFET supplies a squib of automobile air bag systems with load current. The power MOSFET Q.sub.1 provides squib Z.sub.L with the load current, and load current signal which outputs from shunt resistor R.sub.s is provided an operational amplifier consisting of transistors Q.sub.4 -Q.sub.10 with a negative feedback signal, so that the load current to be supplied to the squib Z.sub.L is restricted. The negative feedback operation is interrupted by load current function interruption signal which inputs to terminal T.sub.6. A circuit which consists of two current mirror circuits composed of transistors Q.sub.4 -Q.sub.10 and constant current source I.sub.4 supplies the operational amplifier with constant current to interrupt the feedback operation.
Claims14
A semiconductor integrated circuit comprising
- a backup power supply means,
- an operational amplifier means for supplying a load with a load current from a power amplifier means and having a load current limit function for limiting the load current to provide an input stage with a negative feedback signal of a load current signal corresponding to the load current, and
- a load current limit function interruption means for interrupting the negative feedback operation of the operational amplifier means with an interrupting signal of the load current limit function,
- wherein the operational amplifier means and the load current limit function interruption means are backed up by the backup power supply means, the load current limit function interruption means consists of a constant current circuit means for controlling interruption of the negative feedback operation to supply the operational amplifier with a constant current.
Dependencies are inferred from the claim text.