Patent ID: 6232781
Filing Date: 2001-05-15
Classification: F02D,G01R,Y02T

Abstract:
A short circuit detection device for an electrical load receiving a load current from a voltage source via a power output stage, the power output stage having at least two power switches and a control device outputting control signals for controlling the power switches, the power switches including a high-side switch and a low-side switch which, together with the load, form a load circuit, the short-circuit detection device comprising:a measuring device connected in parallel with a load circuit formed by a high-side switch, a load, and a low-side switch, the high-side switch having a first terminal connected to an input of a voltage source and having a second terminal switchably connected to the first terminal of the high-side switch, the low side switch having a first terminal connected to an output ground of the voltage source and a second terminal switchably connected to the first terminal of the low-side switch, said measuring device including a voltage divider with two resistors and a tap between said two resistors, said tap being connected to a terminal selected from the group consisting of the second terminal of the low-side-switch and the second terminal of the high-side switch, and said tap carrying a diagnostic voltage as an output signal of said measuring device, the second reference voltage being at a lower voltage level than a voltage level at the first reference voltage; anda diagnostic device for detecting faults, said diagnostic device including a window comparator connected to receive the diagnostic voltage from said measuring device and two constant reference values.