Q:Switching power supply (AC-DC) use notes and tips

??Fourth, in order to achieve full heat effect, generally installed in the air convection conditions good position or installed in the chassis shell through the shell will heat out. ??5, LED switching power supply factory before the addition of resistive load, if used in capacitive or emotional load, should be preceded by the order to explain ??Sixth, for the dual output symmetrical load, the preferred use of symmetrical output power ??Seven, the power supply FG ungrounded users, hand touch the shell or the output of Ma electrical feeling is a normal phenomenon, floating when the FG on the earth about 110V AC output, which is the power of the internal structure of the decision.

Q:What is the PWM high-frequency switching power supply

PWM-type high-frequency switching power supply is the use of pulse width modulation (PWM), referred to as pulse width modulation, is the use of microprocessor digital output to control the analog circuit is a very effective technology, widely used in measurement, communication Power control and transformation in many areas of power. PWM switch regulator or steady current power supply basic working principle is in the input voltage changes, internal parameters change, external load changes in the case, the control circuit through the control signal and the difference between the reference signal closed-loop feedback, adjust the main circuit switching device Of the conduction pulse width, making the switching power supply output voltage or current control signal is stable.

Q:I made a switching power supply, using boost dc-dc transform, input 18V, output 30-36V variable. Found that the output voltage has 300mv ripple and 1V burr. Has been added 10mh inductance and 6600uf capacitor filter. Switch tube plus RCD buffer Output with choke and EMI filter,

Output in series with an inductor and then a capacitor in parallel LC filter circuit try to see if feasible?

Q:Such as my primary with double shares 0.51 line, the secondary with four shares 0.51 line, if the secondary I used two 0.71 lines to replace the four shares of 0.51 line influential?

If the skeleton of the transformer can be around, you can, with the purpose of multi-strand line: mainly to increase the coupling force of magnetic field lines, is conducive to EMC, as well as reduce the skin effect, of course, when the pin winding, too rough , Will generally be made in the form of flying line. The final choice or to cost, performance, easy to set up for the integrated consideration.

Q:How to choose the switching power supply frequency?

Have a few points! The size of the input voltage, the choice of transformer magnetic material, the choice of the main switch tube, there is the overall volume requirements can also be said to want to achieve the power density! For example: low-voltage input, such as 6-160VDC, when the pressure on the tube is not high, the switching loss is not dominant, the frequency can be relatively high,

Q:How to identify the computer motherboard and switching power supply, restart, hard disk plug

1, pick up a computer motherboard, in its surrounding observation generally have two rows of pins side by side pile together, and then carefully view, the motherboard plane also note the following words:

Q:Switching power supply, constant current power supply, resistance to the power supply where the benefits?

Capacitive power supply is a constant current power supply, the principle of its buck is the principle of "series circuit resistance divider law", the advantage is very low cost, the circuit is very simple, high efficiency in the case of constant load. It is more shortcomings, the first is the power supply circuit and its output is not isolated from the output, followed by the value of the voltage divider and the load current, not suitable for large changes in the load of the circuit (changes in efficiency will be reduced), not afraid Short circuit but fear of open circuit, and the power supply may be an instantaneous surge current, the surge current will flow through the load, it must be protected. The power factor of the circuit itself is very low.

Q:Switching power supply maintenance methods can be divided into several steps

?2, the first step is completed, after the power is not working properly, and then to detect the power factor module (PFC) and pulse width modulation components (PWM), access to relevant information, familiar with the PFC and PWM module each foot function and Its modules work properly prerequisites.

Q:What is off-line switching power supply

You can not take the power, with their own battery switching power supply

Q:The voltage is too low to refer to the INPUT voltage range below the switching power supply

In general, the input voltage is low, if the output can meet your requirements, there is no big problem. because: The input voltage is low, in the same output power, the input line current will increase, if the margin is not enough, it will obviously heat. If the investigation is reasonable and mature switching power supply program, the input voltage is low, or leave enough margin, or limit the output power, or even into the undervoltage protection state. In addition, the input voltage is low, the switching tube withstand voltage will be reduced, the failure rate will be reduced.