| 摘要 |
<p>Power driver and fail safe circuit (10) for a gas valve in order to open or close the gas valve, comprising: input contacts (11, 12) to which a power source providing a defined DC input power is connectable; an inductance coil (16), a transistor (17) and a resistor (18) being connected in series in such a way that said inductance coil (16) is connected to the drain (19) and said resistor (18) is connected to the source (20) of the transistor; an input capacitor (27) being connected in parallel to the series connection of said inductance coil (16), said transistor (17) and said resistor (18); an output capacitor (28) being connected between output contacts (13, 14) to which a coil (15) of the gas valve is connectable; a first diode (29) being connected in series to the parallel connection of the output capacitor (28) and the coil (15) of the gas valve, wherein said series connection is connected in parallel to said inductance coil (16); a micro controller (30) and a peak current detector (31) both being connected to the gate (32) of said transistor so that the transistor can be turned on into a current conducting mode by a signal provided by the micro controller (30) and that the transistor can be turned off into a current blocking mode by a signal provided by the peak current detector (31).</p> |
