Lighting china
25/09/2013 10:14
Converter output pressure to bring the possibility of failure occurred many times . This voltage LED Lighting china may exceed an internal or an external switching device or the passive components are rated . Also, if you do not take protective measures in case of operation of the circuit , it will give users a potentially dangerous and may damage the connected load .
When the load current path is removed, the output voltage rises until the zener diode ZD1 open while current flows through RPRO and RSET ground . Output current is determined by the series combination RPRO and RSET decision because after VFB is driven internal bandgap reference voltage equal to VREF. Consequently, the output protection current default:
We choose a Zener diode voltage applied to the normal circuit operation during which no current flows through it . To ensure that the diode is completely closed during normal operation , the selected voltage should be at least higher than the maximum load voltage of 2V, but smaller than LED Down lights the boost converter provides the maximum output voltage. Thus, the circuit designers will not often be forced to increase the output capacitor C2 and C3 and the rated voltage clamping diode SD1 . Output voltage is controlled Zener diode voltage and the reference voltage and :
By balancing circuit protection period of the LED current sensing error and power to choose RPRO values. In fact , RPRO the value should be as large as possible in order to minimize the power consumption of the Zener diode :
