A drive circuit for operating a solenoid includes a main switch and a charge pump circuit. The main switch is coupled in series with a coil of the solenoid. The main switch is configured to selectively enable current flow from a voltage source according to a main switching signal to translate a poppet of the solenoid between an opened position and a closed position. The charge pump circuit is coupled to the voltage source. The charge pump circuit is configured to discharge through the coil to translate the poppet from the closed position to the opened position, and to charge when the poppet is held in the opened position.

Methods and systems are provided for a solenoid actuator. In one example, a method may include adjusting a switching frequency during an activation cycle of the solenoid actuator to a lower switching frequency relative to other phases of the activation cycle.

An inductive driver circuit with improved speed of clamping down a powered solenoid element, which solenoid exhibits inductive properties, for purposes of rapid shut down of the solenoid.

An electromagnetic relay includes a fixed contact, a moving contact, an electromagnet device, and a second coil. The moving contact moves from a closed position where the moving contact is in contact with the fixed contact to an open position where the moving contact is out of contact with the fixed contact, and vice versa. The electromagnet device includes a first coil and a mover. The mover is actuated on receiving a magnetic flux generated when a current flows through the first coil to move the moving contact from one of the closed position or the open position to the other position. The second coil gives, when a current flows through the second coil, at least a magnetic flux, of which a direction is opposite from a direction of the magnetic flux generated by the first coil, to the mover.

Embodiments of a discharge circuit are disclosed for quickly and safely discharging energy from an inductor load. The discharge circuit comprises a first switch, a second switch and a voltage regulator. The inductor load couples between the first switch and the second switch. During fast demagnetization, a high side switch is tuned off to decouple the load from a voltage source and the second switch is turned on. Voltage on one end of the load is pushed high and maintained at a predetermined level due to the voltage regulator. The predetermined voltage pulls down the current at the inductive load and causes temperature of the discharge circuit going up quickly. Once the temperature reaches a predetermined threshold, a comparing circuit outputs a signal to a driver and eventually pulls down voltage of the inductor load for low-power demagnetization.

A solenoid is latched in an energized position by a residual magnetic field established by a pulse of current. A degaussing current is selectively applied from a capacitor to unlatch the solenoid. Fail-safe return to the de-energized position occurs when the supply of power is lost.

A fluid injector comprising a coil arranged to drive a pump from a first state to a second state when energized, so as to pump a dosing fluid; a PN junction electrically arranged across the coil to discharge energy stored in the coil when the voltage across the coil is above a threshold. In one particular embodiment, the fluid injector is a selective catalytic reduction dosing fluid injector.

De-magnetization protection is provided for electro-permanent magnets during information handling system manufacture and use by monitoring thermal conditions at the information handling systems to detect a thermal state associated with de-magnetization and commanding the electro-permanent magnets to an off state so that both magnets in the electro-permanent magnet have opposing polarities. The opposing polarities tend to stabilize magnet polarity to prevent de-magnetization during increased temperatures. Normal operations are then re-enabled once temperatures decrease.

A drive circuit anomaly diagnosing device of the present invention performs an anomaly diagnosis on a drive circuit including a power supply line on which a solenoid is disposed midway, a main switch disposed on the power source side relative to the solenoid, a first diode disposed on a protection line connecting a point between the main switch and the solenoid to ground with a forward direction corresponding to a direction from the ground side to the power source side, and a first capacitor interposed on a first line connecting a point between the protection line and the solenoid to the ground midway on the power supply line, the drive circuit being configured to supply power to the solenoid, on the basis of a current detected by a first current sensor disposed upstream of the main switch on the power supply line.

An electromagnet device moves two moving contacts from one of a closed position or an open position to the other position when an electric current flows through a coil. A regenerative current coming from the coil flows through a regeneration unit when the coil makes a transition from an energized state where the coil is supplied with an electric current from a power supply to a non-energized state where the coil is supplied with no electric current from the power supply. The control unit causes the regenerative current to flow through a load by controlling a switch when the coil makes the transition from the energized state to the non-energized state.