A relay driver circuit is connected between an upper stage relay and a lower stage relay and is configured to be driven in response to driving of the upper relay. The relay driver circuit drives the lower stage relay. The relay driver circuit includes a semiconductor component, a control input line, a protective component, and a buffer circuit. The semiconductor component switches on and off the lower relay. The control input line is electrically connected to a control terminal of the semiconductor component. A power supply voltage is applied to the control input line via the upper stage relay. The protective component is connected in the control input line to protect the semiconductor component. The buffer circuit is connected between the protective component in the control input line and the control terminal of the semiconductor component to compensate for a voltage drop due to the protective component.

A relay driver circuit is connected between an upper stage relay and a lower stage relay and is configured to be driven in response to driving of the upper relay. The relay driver circuit drives the lower stage relay. The relay driver circuit includes a semiconductor component, a control input line, a protective component, and a buffer circuit. The semiconductor component switches on and off the lower relay. The control input line is electrically connected to a control terminal of the semiconductor component. A power supply voltage is applied to the control input line via the upper stage relay. The protective component is connected in the control input line to protect the semiconductor component. The buffer circuit is connected between the protective component in the control input line and the control terminal of the semiconductor component to compensate for a voltage drop due to the protective component.

An embodiment circuit comprises high-side and low-side switches arranged between supply and reference nodes, and having an intermediate node. A switching control signal is applied with opposite polarities to the high-side and low-side switches. An inductive load is coupled between the intermediate node and one of the supply and reference nodes. Current sensing circuitry is configured to sample a first value of the load current flowing in one of the high-side and low-side switches before a commutation of the switching control signal, sample a second value of the load current flowing in the other of the high-side and low-side switches after the commutation of the switching control signal, sample a third value of the load current flowing in the other of the high-side and low-side switches after the second sampling, and generate a failure signal as a function of the first, second and third sampled values of the load current.

A relay control apparatus for a relay including a contact connected between a positive electrode of a battery and a load, and a coil connected between a relay power terminal and a ground in which the contact moves to a closed position when the coil is energized. The relay control apparatus includes a coil control switch which is turned on in response to a first switching signal having a voltage level that is equal to or higher than a first threshold voltage in response to a relay on-command, and a relay holding circuit configured to store emergency power using power supplied from the battery.

A relay control apparatus for a relay including a contact connected between a positive electrode of a battery and a load, and a coil connected between a relay power terminal and a ground in which the contact moves to a closed position when the coil is energized. The relay control apparatus includes a coil control switch which is turned on in response to a first switching signal having a voltage level that is equal to or higher than a first threshold voltage in response to a relay on-command, and a relay holding circuit configured to store emergency power using power supplied from the battery.

A bus bar including a first end comprising a first material and a second end comprising a second material and a method of manufacture are provided. The first end is designed to be coupled to a terminal of a first battery cell of a battery module and includes a first collar disposed on the first end designed to receive and surround the terminal of the first battery cell of the battery module. The second end is designed to be coupled to a terminal of a second battery cell of the battery module and includes a second collar disposed on the second end designed to receive and surround the terminal of the second battery of the battery module. The first and second batteries of the battery module are adjacent to one another. Moreover, the bus bar includes a joint electrically and mechanically coupling the first end and the second end.

A bus bar including a first end comprising a first material and a second end comprising a second material and a method of manufacture are provided. The first end is designed to be coupled to a terminal of a first battery cell of a battery module and includes a first collar disposed on the first end designed to receive and surround the terminal of the first battery cell of the battery module. The second end is designed to be coupled to a terminal of a second battery cell of the battery module and includes a second collar disposed on the second end designed to receive and surround the terminal of the second battery of the battery module. The first and second batteries of the battery module are adjacent to one another. Moreover, the bus bar includes a joint electrically and mechanically coupling the first end and the second end.

A pulse control device 10 comprises: a switch output unit 100 which generates a pulse output voltage Vo from a direct-current input voltage Vi and supplies the pulse output voltage Vo to a load (such as a relay coil 21 of a mechanical relay 20); a low-pass filter unit 300 which receives a feedback input of the pulse output voltage Vo and generates a feedback voltage Vfb; and an output feedback control unit 200 which receives an input of the feedback voltage Vfb and controls the switch output unit 100 so that an average value of the pulse output voltage Vo becomes constant. The low-pass filter unit 300 may be configured without a coil.

A pulse control device 10 comprises: a switch output unit 100 which generates a pulse output voltage Vo from a direct-current input voltage Vi and supplies the pulse output voltage Vo to a load (such as a relay coil 21 of a mechanical relay 20); a low-pass filter unit 300 which receives a feedback input of the pulse output voltage Vo and generates a feedback voltage Vfb; and an output feedback control unit 200 which receives an input of the feedback voltage Vfb and controls the switch output unit 100 so that an average value of the pulse output voltage Vo becomes constant. The low-pass filter unit 300 may be configured without a coil.

A method of detecting welded contacts in a relay. The method includes performing, at a first point in time, the applying of a drive to the activation coil to conduct a coil current through the activation coil, the coil current increasing to a first current level, the first current level being less than a pull-in current of the relay; responsive to the coil current reaching the first current level, turning off the drive to the activation coil to discharge the coil current at a first clamping voltage; and measuring a first discharge time corresponding to a first inductance from the turning off of the drive to the activation coil to the coil current reaching a second current level, the second current level being less than the first current level. These operations are repeated at a second point in time to obtain a second inductance. Comparison of the first inductance and second inductance determines whether a difference between the first and second inductances exceeds a comparison criterion.