Abstract: A power on reset circuit includes a threshold detector circuit. The threshold detector circuit includes a power supply voltage, a voltage comparator, first circuitry, second circuitry, and third circuitry. The voltage comparator has first and second input terminals, and an output terminal to provide a reset signal. The first circuitry is operable to convert the power supply voltage to a sensed current, and provides a positive temperature coefficient to the sensed current. The second circuitry is operable to generate, based on the sensed current, a temperature-dependent voltage corresponding to the power supply voltage and to couple the temperature-dependent voltage to the first input of the voltage comparator. The third circuitry is operable to generate, based on the sensed current, a reference voltage and to couple the reference voltage to the second input of the voltage comparator.

Abstract: A system for diagnosing a driver and detecting circuit anomalies therein includes: voltage comparator circuits for generating diagnostic logic signals, each of which indicates the existence of a corresponding type of anomaly; and a coding circuit to receive the diagnostic logic signals and to output information relating to an overall operating state of the driver. The coding circuit includes a first portion to provide at its output first logic input signals indicating the last anomaly to occur since a system reset operation. The coding circuit also includes a second portion for coding the first logic input signals. The second portion includes a sequential logic network to receive the first logic input signals and at least one second logic signal indicating the current operating phase of the driver. The second portion provides, as a function of the first and second logic signals, a stable internal state to determine the output information in the form of an N bit coded word.

Abstract: A protection circuit of a diagnostic output line (K-line) of a control unit for protection of the control unit in the event of a ground disconnection or of a “below ground” condition is provided. The diagnostic output line includes a first interface DMOS transistor with a source connected to ground and a drain coupled to the diagnostic output line through a second DMOS transistor with a source connected to the output line and a drain connected to the source of the first DMOS transistor. The protection circuit also includes a comparator for the voltage of the diagnostic output line with the potential of the ground node, and a two-input logic gate, whose output controls a current generator forcing a current, limited by a resistor, on the diagnostic output line.

Abstract: A troubleshooting circuit for locating malfunctions while driving an electric load by means of a bridge stage (M1, M2, M3, M4) which is connected between ground (GND) and the power supply (+VCC) in series with first and second resistors (Rsl, Rsh), respectively. First (COMP1) and second (COMP2) threshold comparators are coupled to the first resistor to sense a short-circuit to battery (+VCC) and an open-load condition, respectively. Coupled to the second resistor is a third threshold comparator (COMP3) adapted to sense a short-circuit to ground. The output signals from the comparators are sampled through flip-flops (FF1, FF2, FF3, FF4, FF5, FF6) upon a transistor in the bridge being switched to the off state.

Abstract: A circuit for diagnosing the state of a load connected to a driver includes a DMOS transistor interposed between a terminal of the load and voltage comparator circuits. The DMOS transistor limits the maximum voltage input to the comparators to thereby reduce the circuit area occupied by the comparators and consequently to reduce the cost of the diagnosis circuit.