Industry News
Switching power use should pay attention to what the problem
First, when the most recently used positively to negatively charged transformer chip, found insufficient negative voltage output when the load is disconnected, find the voltage is restored, when the post-stage circuit began to suspect a problem, but when using the regulated power supply when a negative voltage is no current limiting, and when the current file using a multimeter test and found that the current is only 50mA, and later found a large inductance when I put the chip output positive line in series to remove, the output is normal. Therefore, in normal operation 5V switching power supply, the input voltage of the power supply lines large inductor is added, although there are separated out the role of the DC component to some extent, but the same effects of the switching power supply.
When it comes to the use of the problem, do not talk about common faults visit:
1, no DC voltage output or voltage output is unstable
If the fuse is intact, under load conditions, no output DC voltage levels. This is mainly due to the following reasons: the power of the open circuit, short circuit, overvoltage, overcurrent protection circuit fails, the auxiliary power failure, the oscillation circuit is not working, power overload, high frequency rectifier diode rectifier filter circuit breakdown, filter capacitor leakage and the like.
2, the power load is low
Power load capacity of poor is a common fault, usually appears in older or long working hours power supply, the main reason is the aging of the various components, job insecurity switch tube, and so there is no time for cooling. Should focus on checking whether the heat leakage Zener diode, rectifier diode damage, high voltage filter capacitor damage.
3, blown fuse
Under normal circumstances, the power line fuse description of internal problems. Since the power supply to operate at high voltage, high current, grid voltage fluctuations, surges can cause momentary increase in the supply current is leaving the fuse. The focus should check the power input of the rectifier diodes, high voltage electrolytic capacitors, inverter power switches, etc., check that the presence or absence of this component breakdown, open, damage.
Although switching power supply with high efficiency, but after all, not 100%, and the thermal resistance of 12V switching power supply chip is relatively small, the heat capacity is relatively poor, so be sure to calculate the voltage and current required by the system to calculate the system's power consumption, and then calculate the power dissipated in the switch on the power consumption of the chip based on the efficiency curve. By calculating the thermal resistance of the chip temperature exceeds the chip can withstand temperatures. Then stay out of the case of a certain margin, select the chip.
When it comes to the use of the problem, do not talk about common faults visit:
1, no DC voltage output or voltage output is unstable
If the fuse is intact, under load conditions, no output DC voltage levels. This is mainly due to the following reasons: the power of the open circuit, short circuit, overvoltage, overcurrent protection circuit fails, the auxiliary power failure, the oscillation circuit is not working, power overload, high frequency rectifier diode rectifier filter circuit breakdown, filter capacitor leakage and the like.
2, the power load is low
Power load capacity of poor is a common fault, usually appears in older or long working hours power supply, the main reason is the aging of the various components, job insecurity switch tube, and so there is no time for cooling. Should focus on checking whether the heat leakage Zener diode, rectifier diode damage, high voltage filter capacitor damage.
3, blown fuse
Under normal circumstances, the power line fuse description of internal problems. Since the power supply to operate at high voltage, high current, grid voltage fluctuations, surges can cause momentary increase in the supply current is leaving the fuse. The focus should check the power input of the rectifier diodes, high voltage electrolytic capacitors, inverter power switches, etc., check that the presence or absence of this component breakdown, open, damage.
Although switching power supply with high efficiency, but after all, not 100%, and the thermal resistance of 12V switching power supply chip is relatively small, the heat capacity is relatively poor, so be sure to calculate the voltage and current required by the system to calculate the system's power consumption, and then calculate the power dissipated in the switch on the power consumption of the chip based on the efficiency curve. By calculating the thermal resistance of the chip temperature exceeds the chip can withstand temperatures. Then stay out of the case of a certain margin, select the chip.
