초록 ▼

A driver circuit for a latching type valve is provided which utilizes an electronic switch assembly to provide the dual polarity necessary to actuate the latching type valve to both its open and closed states. The driver circuitry includes a microprocessor and a slope detector circuit for monitoring

A driver circuit for a latching type valve is provided which utilizes an electronic switch assembly to provide the dual polarity necessary to actuate the latching type valve to both its open and closed states. The driver circuitry includes a microprocessor and a slope detector circuit for monitoring the coil current used to energize the valve solenoid to determine when the valve armature has moved to its fully actuated position. The driver circuit preferably utilizes power MOSFET devices in the switch assembly configured into an H-bridge to drive the solenoid coil. Advantageously, the user of power MOSFET devices eliminates the necessity for a current sense resistor in the control circuitry, thereby decreasing power dissipation and increasing efficiency of the drive circuit, thereby prolonging the battery life used to drive the valve. A pulse of fixed duration may be utilized to transition the valve to an OFF position, or a second slope detector may be implemented to control the transition to the OFF position in like manner. Monitoring of the actual time required to actuate the valve may be utilized to signal low battery voltage or a failed valve, if desired.

대표청구항 ▼

[ What is claimed is:] [10.]10. A solenoid driver circuit, comprising:a first, second, third, and fourth MOSFET configured in an H-bridge having a coupling for an external source of electric power at a first node between said first and said second MOSFETs, and a coupling for a circuit return at a se

[ What is claimed is:] [10.]10. A solenoid driver circuit, comprising:a first, second, third, and fourth MOSFET configured in an H-bridge having a coupling for an external source of electric power at a first node between said first and said second MOSFETs, and a coupling for a circuit return at a second node between said third and said fourth MOSFETs, said H-bridge further providing a coupling to a solenoid at a third node between said first and said third MOSFETs and at a fourth node between said second and said fourth MOSFETs;a first slope detection circuit having an input coupled to said fourth node, said first slope detection circuit providing an output indication of a slope of a voltage developed across said fourth MOSFET; anda microprocessor having an output drivably coupled to each of said MOSFETs and an input coupled to said output of said first slope detection circuit, and wherein said microprocessor turns on said first and fourth MOSFETs until said output of said first slope detection circuit indicates a positive slope after indication of negative slope.