The traditional quasi resonant and constant pressure clamping method can make current cut-off delay shorter and linearity better.But their control circuits are complex and the introduced capacitance is easy in resonance with coils

which can aggravate jittering on the both ends of trailing edge.For this reason

it is proposed that using TVS and SIDAC devices to realize passive constant-voltage clamping circuit.It can not only make circuit simple

but also reduce jittering on the both ends of trailing edge for the lower junction capacitance in the two devices.Passive constant-voltage clamping circuit composed by TVS and SIDAC is analyzed

and it manifests that the designed circuits with two devices both meet constant pressure clamping requirements.Experimental results show that the passive constant pressure clamping method can make the current decline linearity better

jittering on the both ends of trailing edge lower and circuit simpler.