CIRCUIT FOR CONTROLLING EITHER THE CURRENT THROUGH AN ELECTRIC CONTROL DEVICE OR THE VOLTAGE ACROSS SAID ELECTRIC CONTROL DEVICE

摘要

The present invention relates to a circuit (100) for controlling the current in an electrical control unit. Said circuit (100) comprises a bridge (101) provided with four terminals (105, 106, 107, 108) and four controlled switches (111, 112, 113, 114), a power supply (109) for the bridge, means (123) for producing a measurement signal representative of the current in the electrical unit (110), means (116) for comparing the measurement signal with a high threshold signal, and means (117) for comparing the measurement signal with a low threshold signal. The circuit (100) further includes counting means (115) for detecting when the measurement signal reaches the high threshold signal for the second time and when the measurement signal reaches the low threshold signal for the second time, and means (115) for controlling the switches, these means (115) authorising at least three of the following four states: a first state wherein the first (111) and fourth (112) switches are closed and the second (114) and third (113) switches are open, a second state wherein the second (114) and third (113) switches are closed and the first (111) and fourth (112) switches are open, and at least one of the following two states: a third state wherein the third (113) and fourth (112) switches are closed and the first (111) and second (114) switches are open, and a fourth state wherein the first (111) and second (114) switches are closed and the third (113) and fourth (112) switches are open. One application of the invention is in the field that involves current control in actuators used for electromagnetic valves in motor vehicles.