| 摘要 |
<p>A method and a circuit for disabling a converter while allowing its self-recovery, the converter circuit comprising a transformer (T1) provided with an auxiliary winding (L1) self-supplying, after start-up, an integrated circuit (IC) containing the programming, driving, controlling and protecting circuitry of the converter, a start-up circuit directly connected to a power source, a rectifying circuit (D1, C1) of the voltage induced in the auxiliary winding (L1), supplying through a voltage regulator stage (R1, Z1, T1) the integrated circuit at a regulated voltage (Vreg), at least an external line comprising a sensor of an electrical or physical quantity to be monitored (NTC, Rs), biased to a reference voltage, functionally coupled to a disable input pin (A-REC) of the integrated circuit for disabling it when a certain threshold value is surpassed. The method consists in using the regulated self-supply voltage of the converter (Vreg) as biasing voltage of the external sensor line and as reference voltage of an hysteresis comparator monitoring the signal representing the monitored quantity produced an the external sensor line. Upon the switching of the hysteresis comparator the integrated converter circuit (IC) is turned off and the limiting value of the rectified voltage (Vcc) self-supplying the integrated converter circuit (IC) is markedly reduced by short-circuiting to ground a portion (Z4, Z5) of a sectionable voltage clamp chain (Z2, Z3, Z4, Z5) coupled between the output (Vcc) of the rectifying circuit (D1, C1) and a common ground node of the circuit. <IMAGE></p> |
