Solenoid assembly with included constant-current controller circuit

A constant-current control circuit situated on a printed circuit board (PCB) that is integrated with and made a part of an actuator assembly used to drive an associated electromechanical device, said constant-current control circuit comprising:

• a switching circuit including:
• a source voltage;
• a primary switch connected with a coil of said actuator assembly, wherein said primary switch is a gallium nitride field effect transistor (GaNFET) switch;
• and
• a secondary switch connected with said coil, wherein said coil has an inductance,
• a pulse-width modulation (PWM) controller configured to cause a periodic current in said coil to become constant by increasing a PWM switching frequency to a threshold frequency having a switching period that is less than a circuit time constant,
• wherein a boundary current and a peak current approach the same constant value as said PWM switching frequency increases,
• wherein, from t0 to ton, said GaNFET primary switch is closed and said secondary switch is open, said source voltage is applied across said coil, and a counter electromotive force (EMF) decays until the voltage across said coil equals said source voltage at ton, thereby allowing current to flow through said coil, and
• wherein, from ton to T, said GaNFET primary switch is open and said secondary switch is closed, and a positive EMF equal to said source voltage of said PCB is applied across said coil until said positive EMF decays to zero at T, such that said current continues to flow through said coil without said source voltage being applied across said coil,
• wherein an average current in said coil is dependent upon a rate at which said GaNFET primary switch and said secondary switch are opened and closed with respect to each other, and wherein the rate is the PWM switching frequency.

A constant-current control circuit situated on a printed circuit board (PCB) that is integrated with and made a part of an actuator assembly used to drive an associated electromechanical device, said constant-current control circuit comprising:

• a switching circuit including:
• a source voltage;
• a primary switch connected with a coil of said actuator assembly, wherein said primary switch is a gallium nitride field effect transistor (GaNFET) switch;
• and
• a secondary switch connected with said coil, wherein said coil has an inductance,
• wherein, from t0 to ton, said GaNFET primary switch is closed and said secondary switch is open, said source voltage is applied across said coil, and a counter electromotive force (EMF) decays until the boltage across said coil equals said source voltage at ton, thereby allowing current to flow through said coil, and
• wherein, from ton to T, said GaNFET primary switch is open and said secondary switch is closed, and a positive EMF equal to said source voltage of said PCB is applied across said coil until said positive EMF decays to zero at T, such that said current continues to flow through said coil without said source voltage being applied across said coil, wherein
• said GaNFET primary switch has a width and a length of approximately 1.35 mm and a thickness of approximately 0.625 mm.

A constant-current control circuit situated on a printed circuit board (PCB) that is integrated with and made a part of an actuator assembly used to drive an associated electromechanical device, said constant-current control circuit comprising:

• a switching circuit including:
• a source voltage;
• a primary switch connected with a coil of said actuator assembly, wherein said primary switch is a gallium nitride field effect transistor (GaNFET) switch;
• and
• a secondary switch connected with said coil, wherein said coil has an inductance,
• wherein, from t0 to ton, said GaNFET primary switch is closed and said secondary switch is open, said source voltage is applied across said coil, and a counter electromotive force (EMF) decays until the voltage across said coil equals said source voltage at ton, thereby allowing current to flow through said coil,
• wherein, from ton to T, said GaNFET primary switch is open and said secondary switch is closed, and a positive EMF equal to said source voltage of said PCB is applied across said coil until said positive EMF decays to zero at T, such that said current continues to flow through said coil without said source voltage being applied across said coil,
• wherein said control circuit is configured to maintain said constant current flow by increasing a PWM switching frequency at which said GaNFET primary switch and said secondary switch are opened and closed with respect to each other, and
• wherein said associated electromechanical device is an electromechanical door latch or an electromechanical strike, and wherein said control circuit controls power to said electromechanical door latch or said electromechanical strike by adjusting a duty ratio of said GaNFET primary switch.

A constant-current control circuit situated on a printed circuit board (PCB) that is integrated with and made a part of an actuator assembly used to drive an associated electromechanical device, said constant-current control circuit comprising:

• a switching circuit including:
• a source voltage;
• a primary switch connected with a coil of said actuator assembly, wherein said primary switch is a gallium nitride field effect transistor (GaNFET) switch;
• and
• a secondary switch connected with said coil, wherein said coil has an inductance;
• and
• a pulse-width modulation (PWM) controller for generating signals to synchronously alternate on-times and off-times of the GaNFET primary switch and the secondary switch, respectively, and wherein said control circuit controls power to said electromechanical door latch or said electromechanical strike by adjusting a duty ratio of said GaNFET primary switch and said secondary switch,
• wherein, from t0 to ton, said GaNFET primary switch is closed and said secondary switch is open, said source voltage is applied across said coil, and a counter electromotive force (EMF) decays until the voltage across said coil equals said source voltage at ton, thereby allowing current to flow through said coil, and
• wherein, from ton to T, said GaNFET primary switch is open and said secondary switch is closed, and a positive EMF equal to said source voltage of said PCB is applied across said coil until said positive EMF decays to zero at T, such that said current continues to flow through said coil without said source voltage being applied across said coil, wherein said associated electromechanical device is an electromechanical door latch or an electromechanical strike.