JPS647857A - Deflection stopping and protecting circuit - Google Patents

Abstract

PURPOSE:To prevent the burning of an image receiving tube in the case of a deflection stopping accident by stopping the generation of a high voltage due to a high voltage generating circuit when a horizontal, vertical deflection or the both deflection are stopped. CONSTITUTION:A first direct current voltage E1 obtained by detecting the presence and absence of a horizontal or a vertical deflection and a second direct current E2 obtained by detecting the presence and absence of the other one deflection are compared by a comparator 12. The first direct current voltage E1 is higher than the second direct current voltage E2 at a normal operating time, a lower valve than a circuit operating source voltage E0 is set, at a deflection action stopping time, the second direct current voltage E2 is interrupted and the E1 is constituted so as to decrease toward zero. On the other hand, for the second direct current voltage E2, at a normal operating time, a lower value than the first direct current voltage E1 is set, at the deflection action stopping time, the E2 passes over the first direct current voltage E1 and constituted so as to rise toward the circuit operating source voltage value E0 and further, the output of the comparator 12 moves from the normal operating time to the deflection action stopping time, by inverting, the action of a high voltage generating circuit 9 for the anode of an image receiving tube 4 is stopped. Thus, the burning of the fluorescent screen of the image receiving tube 4 in deflection stopping accident is prevented.