Abstract: An integrated high side switch with multi-fault protection. When a fault condition is detected, the switch is turned off. The switch includes a pair of transistors that are connected such that the source of the first transistor is connected with the source of the second transistor. The drain of the first transistor is thus connected to the supply voltage. A first current mirror generates a current sense output. A second current mirror generates an internal current to detect an over current fault condition. The transistors in the current mirrors are connected like the switch transistors. A high voltage operational amplifier and a transistor are used as feedback to insure that the voltage at the output of the current mirrors matches the voltage at the output of the switch. This ensures that the current mirrors generate scaled versions of the current flowing through the switch.

Abstract: An operational amplifier with two differential pairs coupled to different current sources. The gate terminals of the transistors in the first differential pair are used as input terminals providing common mode input for most of the rail-to-rail voltage. The bulk terminals of the transistors in the second differential pair are used as input terminals providing common mode input for the remainder of the rail-to-rail voltage to thereby accomplish full rail-to-rail common mode. By using the bulk terminals of the field effect transistors in the second differential pair, rather than the gate terminals, as the input terminal, the operational amplifier may be constructing in a single well, thereby being compatible with standard digital CMOS processes. Alternatively, the bulk-driven transistors may be replaced with gate-driven depletion type transistors. The high voltage transistors in the output stage further reduce the offset voltage of the operational amplifier.

Abstract: An integrated high side switch with multi-fault protection. When a fault condition is detected, the switch is turned off. The switch includes a pair of transistors that are connected such that the source of the first transistor is connected with the source of the second transistor. The drain of the first transistor is thus connected to the supply voltage. A first current mirror generates a current sense output. A second current mirror generates an internal current to detect an over current fault condition. The transistors in the current mirrors are connected like the switch transistors. A high voltage operational amplifier and a transistor are used as feedback to insure that the voltage at the output of the current mirrors matches the voltage at the output of the switch. This ensures that the current mirrors generate scaled versions of the current flowing through the switch.