Patent ID: 11904333
Assignee: CAPSTAN AG SYSTEMS, INC.
Field: Chemical engineering (Chemistry)
Classification: CPC B  A  H  Y | IPC A  B  H

Claim 13:
14. A drive circuit for controlling a solenoid valve having a solenoid coil, the drive circuit comprising:
a first semiconductor device controlled by a pulse-width modulated (PWM) gate signal to energize the solenoid coil and transition the solenoid valve from a first position to a second position;
a flyback circuit coupled with the solenoid coil, the flyback circuit comprising:
a second semiconductor device controlled by a flyback control signal to: (i) enable the flyback circuit when the first semiconductor device is controlled by the PWM gate signal to hold the solenoid valve in the second position, and (ii) disable the flyback circuit when the first semiconductor device is controlled by the PWM gate signal to transition the solenoid valve to the first position; and
a diode coupled in series with the second semiconductor device to slow a decay of a current conducted through the solenoid coil while the solenoid valve is in the second position; and

a controller configured to generate the PWM gate signal to transition the solenoid valve from the first position to the second position, to enable the flyback circuit using the flyback control signal, and to reduce a duty cycle of the PWM gate signal when the flyback circuit is enabled.