Power consumption reduction of a relay circuit for electric vehicles at high operating voltages

Abstract

Device for controlling a relay (R1), wherein the relay (R1) has a relay coil (L), and wherein the relay (R1) has a relay switch (S), and wherein the relay (R1) has an armature, and wherein the device has a switching element (T1), and wherein the device has a driver (TR) for the switching element (T1), and wherein the device has a control device (CTR), and wherein the device has a voltage measurement signal (VMS), and wherein the device has a control input (Sig), and wherein the device has a supply voltage line (VDD), and wherein the device has one of the reference potential lines (GND) at a reference potential, and wherein the device includes a control signal (AS) of the driver (TR) for the switching element (T1), and wherein the control input (Sig) serves to control the state of the relay (R1), and wherein the relay (R1) has an on state in which the relay coil (L) is supplied with a relay current (IRel).is energized and the relay switch (S) is closed, and has an off-state in which the relay coil (L) opens the relay switch (S), so that the relay switch (S) can be in an on-relay state or an off-relay state, wherein the relay coil (L) controls the relay switching state of the relay switch (S) via its magnetic field and the resulting magnetic force on the armature depending on the relay current (IRel), and wherein the electrical relay current (IRel) depends on the switching state of the switching element (T1), and wherein the switching element (T1) connects or disconnects the supply voltage line (VDD) with a first terminal of the relay coil (L) of the relay (R1) depending on the control signal (AS), and wherein the switching element (T1) is used to switch the relay (R1) on and off, and wherein a second terminal of the relay coil (L) is connected to the reference potential line (GND), and wherein theThe device is supplied with electrical energy via the supply voltage line (VDD) by means of a supply voltage (Vbat), wherein the device includes a voltage measuring device (VM) for detecting the voltage value of the supply voltage (Vbat) and generating the corresponding voltage measurement signal (VMS), wherein the voltage measuring device (VM) is connected to the control device (CTR) by means of the voltage measurement signal (VMS), wherein the switching element (T1) can assume an on switching element state and an off switching element state, wherein the control input (Sig) can have a first logic state and a second logic state, wherein an electrical relay current (IRel) flows through the relay coil (L), wherein the electrical relay current (IRel) depends on the switching state of the switching element (T1), and wherein the relay switch (S) is in an on relay switching state and in an off relay switching state.can be a relay switching state and wherein the relay coil (L) controls the relay switching state of the relay switch (S) depending on the relay current (IRel) and wherein the control device (CTR) and the subsequent driver (TR) generate the control signal (AS) depending on the state of the control input (Sig) and the detected value of the supply voltage (VBat) and wherein the control device (CTR) generates a modulation of the relay voltage (VRel) using the control signal (AS) and wherein the control device (CTR) brings the switching element (T1) into the off switching element state when the control input (Sig) has the first logic state, and wherein the control device (CTR) brings the switching element (T1) into the on switching element state when the control input (Sig) has the second logic state and the magnitude of the supply voltage (Vbat) is less than a first threshold value (VNom) and wherein the control device (CTR)The device allows the switching element (T1) to switch back and forth between the on-state and off-state according to the modulation when the control input (Sig) is in the second logic state and the magnitude of the supply voltage (Vbat) is greater than or equal to a first threshold (VNom), wherein, in the on state of the control input (Sig), the device applies a relay voltage (VRel) to the relay coil (L) which deviates from the supply voltage (Vbat) by less than 25% and which is not modulated when the mean relay voltage (VRel,av) is below a threshold (VNom2), and wherein, in the on state of the control input (Sig), the device applies a relay voltage (VRel) to the relay coil (L) which deviates from the magnitude of the supply voltage (Vbat) by less than 25% and which is modulated with a modulation signal, in particular a PWM and / or a PDM signal and / or anotherpulse modulated signal, is modulated when the mean relay voltage (VRel,av) is above the threshold (VNom2).

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