A solenoid control circuit can make measurements during operation to determine the state of a solenoid and can provide for rapid re-energization of a solenoid upon detection of a dropout condition. A method of controlling a solenoid can include closing an input switch, cycling a low side switch based on voltage drop across a resistor, opening the input switch after a time interval, closing the low side switch and driving a discharge switch to control the discharge current rate from an energy storage device to an inductor. The method can include determining a condition of the inductor based on a time interval between actuation of comparators and maintaining a level of energy in the energy storage device sufficient to cause the inductor to produce a magnetic field for actuating a valve.

An apparatus can comprise a circuit and an electrical element coupled to the circuit. The circuit can include a pulse generator to generate an electrical pulse having a first power and a load. The electrical element can be configured to receive heat that is converted into electrical energy by the circuit to apply a second power, greater than the first power, to the load.

A power conversion device includes an inverter, a smoothing capacitor, Y capacitors, and a power supply wiring that electrically connects a DC power supply and the inverter. The power supply wiring includes power terminal portions to which the DC power supply is connected, power terminal portions to which the inverter is connected, and capacitor terminal portions to which the Y capacitors are connected. In the power supply wiring, a parasitic inductance L1 between the power terminal portions and the capacitor terminal portions are made smaller than a parasitic inductance L2 between the power supply terminal portions and the capacitor terminal portions.

A DC-DC converter includes an output-side storage capacitor arrangement which has a parallel circuit formed of an electrolytic capacitor, a ceramic capacitor and a circuit arrangement. The circuit arrangement has a series circuit formed of a hybrid electrolytic capacitor and a suppressor diode as well as a resistance connected in parallel with the hybrid electrolytic capacitor.

A solenoid system includes a solenoid, a primary power source, solenoid control circuitry, flyback charging circuitry, and voltage regulator circuitry. The primary power source is configured to provide a primary voltage to at least the solenoid. The solenoid control circuitry is configured to control current provided to the solenoid. The solenoid generates a flyback voltage spike each instance the current provided to the solenoid is interrupted as controlled by the solenoid control circuitry. The flyback charging circuitry is configured to charge in response to each instance of the flyback voltage spike. The voltage regulator circuitry is configured to provide a regulated supply voltage from the flyback charging circuitry to the solenoid control circuitry if the flyback charging circuitry is charged to a secondary voltage that is greater than the primary voltage.

A method includes switching a switching circuit of the switched-mode power supply in a synchronous mode by turning on and off switches of the switching circuit in synchrony with a clock signal, wherein the switching circuit is coupled to an inductive element, and wherein the synchronous mode comprises a charging phase and a discharging phase; switching the switching circuit in an asynchronous mode by turning on and off switches of the switching circuit without being synchronized with the clock signal, wherein the asynchronous mode comprises a charging phase and a discharging phase; charging the inductive element during the charging phase of the synchronous mode; discharging the inductive element during the discharging phase of the synchronous mode; charging the inductive element during the charging phase of the asynchronous mode; and discharging the inductive element during the discharging phase of the asynchronous mode.

A circuit for polarizing magnetic material using a magnetic field of an excitation coil includes a port configured to provide a connection with a DC power supply. The circuit also includes at least one capacitor and driver circuitry configured to drive the excitation coil and the at least one capacitor. The driver circuitry is configured to discharge the excitation coil to the DC power supply via the at least one capacitor.

A method includes switching a switching circuit of the switched-mode power supply in a synchronous mode by turning on and off switches of the switching circuit in synchrony with a clock signal, wherein the switching circuit is coupled to an inductive element, and wherein the synchronous mode comprises a charging phase and a discharging phase; switching the switching circuit in an asynchronous mode by turning on and off switches of the switching circuit without being synchronized with the clock signal, wherein the asynchronous mode comprises a charging phase and a discharging phase; charging the inductive element during the charging phase of the synchronous mode; discharging the inductive element during the discharging phase of the synchronous mode; charging the inductive element during the charging phase of the asynchronous mode; and discharging the inductive element during the discharging phase of the asynchronous mode.

A PWM signal generator to provide a supply current to an electrical load generates PWM signals at a first frequency, the PWM signals having a duty cycle. Operating the generator involves receiving a set point signal indicative of a target average value for the supply current, sensing a sensing signal indicative of a current actual value of the supply current, performing a closed-loop control of the supply current targeting the target value for the supply current via a controller such as a PID Controller which controls the duty cycle of the PWM signals generated by the PWM signal generator as a function of the offset of the sensing signal with respect to the set point signal.

An apparatus for driving an inductive load, includes a switching element provided in a current flowing path of the inductive load, a diode connected to the inductive load in parallel, a current detecting resistor detecting current flowing through the inductive load, a peak hold circuit holding voltage detected by the current detecting resistor when the switching element is on, when the switching element is off, and a control section controlling current flowing through the inductive load by turning on/off of the switching element at a duty ratio in response to a target current value while the control section performs feedback control of output of the peak hold circuit. The control section controls current that flows through the inductive load when the duty ratio is larger than a threshold value and controls voltage that applies to the inductive load when the duty ratio is smaller than the threshold value.