The progress of semiconductor technology already made integrated circuit (IC) can replace a lot of
Mechanical relay, but in the circuit of tall voltage big electric current in aleatoric polarity, relay still holds dominant position. However, this kind
Relaycontact bound can bring a trouble to downstream circuit. A kind of way that settles contact bound is a relay and a heat are inserted unplug controller union rises. This kind of controller regards switch system as the method of component below the case that does not close systematic power source, more and more popular now. In the graph 1 in, contact replaces a relay of mechanical connector cite a base. Drive circuit makes relay closes, and of relay close insert heat unplug the input of circuit carries join to arrive power source (28V is in this exemple) . After input power source achieves effective n heat is inserted unplug controller IC1 makes MOSFET of P raceway groove namely Q1 can maintain close condition to amount to 150 Ms the least. Enough of time of this paragraph of defer makes the contact bound in relay disappears. After 150ms defer, grid of IC1 drive MOSFET, make output voltage to swing with the rate of 9V/ms. This kind of controlled brae rate makes starting electric current is decreased to the smallest, reduced pair of heat to insert thereby unplug the stress of the power source with downstream controller, relay and capacitor.
Contact bound example makes clear relay contact bound appears 3 times when peak value of starting surge electric current is 30A about (graph 2) . Coping curve is the output voltage that the unit is 10V/ case, the curve is the input electric current that the unit is 5A/ case below, and outputting laden impedance is as shunt-wound as F of 100 μ 54 Ω . Below these conditions use graph shows circuit 1 times to be able to get better result (graph 3) . The defer that outputs voltage rises clearly, what cause without contact bound is discontinuous. The change that inputs electric current is reduced greatly, before stability is worth 500 MA at stable state, its peak value is less than 1.5A.
