An H-Bridge is used to drive Latching solenoids (e.g. irrigation valves). The switches provide logic levels to control each side of the H-Bridge and drive the solenoid with a set or reset pulse from a charged storage capacitor.
These type of solenoids actuate with a short pulse rather than constant voltage. Actually the solenoids I am using will burn up in 1/4Sec with a constant voltage applied.
I use a boost converter to charge the storage capacitor. It is not shown in this simulation. Instead, the simulation has a current source and a Zener diode.
A bridge short (e.g. change 4 to zero Ohm) that causes the FETs to fail short means they ran in the active mode and dissipated heat until death. If they had failed open that would suggest to much current had fused a circuit element (e.g. wire bond).
The circuit board http://epccs.org/indexes/Board/K3/
