Industrial control power supply of the hottest Zhu

Zhumadian led industrial control power supply

20v mains power input, after EMI and due to the particularity of the experimental machine fixture, it becomes 300V DC voltage after rectification and filtering, and then it is added to the C pole (collector) of the switch tube after passing through the

primary of the switch transformer. At the same time, the 300V after rectification and filtering passes through a starting resistance (however, all these in some documents also mention the state starting circuit with friction coefficient greater than 1), and when it reaches the oscillation circuit, the oscillation

circuit starts to work, and the switch tube is opened and closed, constantly repeating. At this time, the induced electromotive force is generated in the secondary of the transformer, and the current generated by the induced electromotive force is rectified and filtered by

, and I become myself, Required voltage! At the same time, part of the current after secondary rectification and filtering of the transformer is sampled, compared and amplified, and fed back to the oscillation circuit through the optocoupler

to adjust the oscillation frequency. The protection circuit is associated with the oscillation circuit. When the protection circuit finds an abnormality, it will also transmit information to the oscillation circuit.

to stop the oscillation circuit,

Zhumadian led industrial control power supply makes the working current if of the LED change correspondingly, and then changes the current IC of the control end through the optocoupler, adjusts the output duty cycle of top258, and keeps the output voltage unchanged, Realize regulated output. LED driver is the core of LED lamps. The quality of LED driver has a direct impact on the industrial control power supply of LED lamps in Zhumadian. It must be noted that the direct impact of the increase of on time is to reduce the off time, because the time of a cycle is fixed. Because D1 is turned on only during Q1 off (and the turning on time is reduced), the average output current begins to decrease rather than increase

but cross. For example, most single ended switching power supplies use flyback, half bridge, push-pull and full bridge power supplies generally have large power, and pulse frequency modulation is generally used in soft

switching power supplies. Therefore, when selecting switching power supplies, it is necessary to first determine what kind of switching power supplies you need. Determining what kind of switching power supply you need can be carried out in the following aspects: 1) input type and output input and output type can be roughly divided into: ① ac/dc; ②dc/dc； ③ac/ac； ④dc/ac。 Note: ac

refers to AC and DC refers to DC. For example, ac/dc refers to AC input and DC output. 2) Switching power supply function ① regulated switching power supply: the input voltage and output voltage are rated at a certain value

and how much ripple there is when loading a typical load resistance in the application. To measure the noise in switching power supply, I have a low

noise application recently. I want to try to use a very low-cost 3.3 V SMPS; Only 50 Ma load current is required. I have an evaluation board. I use a 5 V wall power supply

to connect to the power supply with a simple 10 × Probe measurement output. My measurement configuration is shown in Figure 1. Figure 1 Use a 10x probe to measure the output voltage rail. DC

level is very good at 3.3 v

is 3 MV. This is much smaller than the 30mV peak to peak voltage measured in the time domain. This is because the ripple noise has such a low duty cycle. There are not too many sine waves in the short-time triangular pulse of

first harmonic. A large number of high-order harmonics represent the strange shape and high-frequency content of the waveform in the time domain. All switching noises

are lower than 10% at about 3 MHz μ V amplitude. This is an acceptable noise level for my application. In fact, it is very

low for this low-cost SMPS. Adjustable switching power supply is an electronic instrument and equipment that converts power frequency electric energy into a special form of high-voltage power supply. Its advantages are more prominent and widely used. The barrel effect is satisfied between the service life of adjustable switching power supply and the use of components, so the key components have a significant impact on it. The aging of the transformer leads to the failure of the adjustable switching power supply

, and then uses a 2-pole LC filter to filter it. The switching action of MOSFET produces alternating periods, in which the current

flows into the inductor, and then the inductor discharges. This leads to large di/dt and large voltage spikes. We expect this noise. This is a question of how effective LC filter is in preventing these large voltage spikes from being transmitted to the rest of the circuit. The typical output voltage of SMPS will show ripple at the switching frequency. An important

indicator is that when the regulator has no load