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Wednesday, June 26, 2013

Complete ATX Power Supply: Circuit




stbblockinggt

300Vdc circuit is powered from circuit bent / primary filter. effects components: Rhv: Resistors limit, then its output voltage to about 270V. R3, R5: The Natural (bait) for Q3. Q3: standby power, 2N60 Mosfet used here. R4: Creating negative feedback voltage, voltage drop on R4 used as a sensor to check the flow through Q3, which will be adjusted through to Q3 operating stable. ZD1: G Stable feet voltage, in order to protect not widened Q3, Q3 avoid being punctured. C34: Capacitor discouraged, Q3 is not protected under voltage breakdown when large cathode of the period reverse scan. R9: resistor potentiometer, create stability (relative) for Q3 G and C foot Q4. L1: Download Q3. L2: Scroll feedback. Q4: Prone to foot pressure distribution G Q3, role reverse-phase voltage feedback. D5: Resetting feedback circuit bent parallel manner to produce voltage (+) at point A. C8: voltage feedback filter. U1: from optical circuit, negative feedback voltage stability STB. R17: Advanced low resistance, with the aim to break the feedback voltage when the voltage Q4 B foot drops to ~ 2V. C4, R6, D3: Eliminate reverse voltage, anti-ranged interrupt. Principle:circuit voltage from 300V adapter / Rhv remaining primary filter through ~ 270V for circuit level. This voltage is divided into two lines: line 1: At PN6 point, the legs D PN4 to Q3. St. 2: Over R3, R5 potentiometer R9 combined bias for Q3, Q4 and for (leg C). Make sure you have assigned to the pressure for G Q4 Q3 Q4 saturated, so if the voltage at ~ 0 G Q3, Q3 lock. Due to the nature (prey) by R3, R5 should open Q3. Current from 270V through L1, DS Q3 down through mass, closed circuit. Since the line passes through L1, the characteristics of inductors (always born through it line by line against the phenomenon of electromagnetic induction) should flow through the L1 does not reach the saturation level at which rising slowly. So the magnetic field generated in the transformer core STB cun increased gradually (from the field). According to Lenz's law of electromagnetic induction, magnetic field increases from core transformer from the STB will rise above all the coils Power Transformer 1 of the induction. voltage induced on L2 is bent by D5 and C8 filter removed 1 dimensional voltage is negative (+) at point A, is stable (relative) with R16, stability depends on the size of T = R16xC8 (time constant - time constant of the RC circuit exit) voltage at point A again through CE U1 (from photosynthesis) to B leg of Q4. Because the voltage is positive so it makes Q4 saturated. When Q4 is saturated voltage at the base of Q4 ~ 0 C, but C pin connector on the back foot G Q4 Q3 should make Q3 UgQ3 ~ 0 keys. When the current through Q3 lock, lose the line through L1, L1 on the field as well loss made ​​on the magnetic core transformer = 0 leads to the induced voltage on the transformer windings STB = 0. Of course, the induced voltage in the coil L2 loss.because the voltage across L2 pressure loss should not give (+) at point A again. However, because C8 loaded (before) so now it makes discharge voltage at point A can not lose right, the exhaust will maintain C8 (+) to add 1 foot B Q4 and Q4 tieps time again to storm peace, continued Key Q3. Go to the voltage (+) by C8 discharge not big enough (≤ 2V), the R17 will interrupt voltage feedback, leg B will reduce the O Q4, Q4 lock. When Q4 lock the bias voltage by R3, R5 and Q3 restored back open. A cycle open / locked start. frequency of oscillation of the circuit: It is determined by L2/C8/R16. This is the serial resonance should occur when the resonance is the max voltage on L2, then the line voltage at point A is enough for max R17 leads, Q4 saturated. If lost, the resonant voltage across L2 min, A min voltage of insufficient pressure drop across R17 brake lock to Q4, Q3 open (fixed) and the current through L1 will be fixed not generate magnetic fields up to induced voltage on all of the transformer coil STB lost. In other words, the oscillation frequency of the circuit by 1/2Πxsqrt (L2xC8R16). fact, the key Q3, the current through L1 not just because of the loss of the transformer core is still (small) rise to power pressure sensors on the way L1 (-) in D Q3, this voltage exists in a very short time (like back in power line scan television, CRT) should be of great value (~ 800V with newer sources ) give rise to two consequences: Effects of C4, R6, D3 as direct feedback circuit. voltage induced in L3 generated by changing magnetic field due to continuous saturation Q2 / lock. This voltage adapter / standby voltage filter removed. St. 1: Resetting / filtered by a 12V feed D9/C15 fluctuations, amplified stimulated. St. 2: Bending / filter by D7/C13/C18 5V for purple wire , lower back pressure through the PS-ON, raising circuit PG algorithms. voltage stabilization: Use OPTO U1. If the output voltage increases (because the oscillation frequency changes), the 5V output increases. When the controller power supply poles of U1 (TL431) from 5V over R27 431 up to the big opening. Notice that 431 emitting diodes connected in series with the OPTO, because the large opening 431 through the diode current (from 5V STB through R30, through the diode, through to mass 431) increases, the light intensity of the diode increases impact resistance RCE CE U1 U1 to decrease, this resistors connected in series from point A to R17 should make the voltage feedback to the B Q4 (through R17) increases, resulting in Q4 lock hoa/Q3 storm earlier than usual. In other words, the opening time of 1 second smaller Q3 will decrease the output voltage to decrease. If output voltage is reduced (due to changes in the oscillation frequency) is a 5V source reduction. When the controller power supply poles of U1 (TL431) from 5V down over R27 431 to make the opening smaller. Notice that 431 emitting diodes connected in series with the OPTO, because the large opening 431 through the diode current (from 5V STB through R30, through the diode, through to mass 431) decreased, reducing the light intensity of the impact CE diode to resistor RCE U1 U1 increases, this resistor in series from point A to R17 should make the voltage feedback to the B Q4 (through R17) decreased, resulting in late Q4 lock hoa/Q3 storms than usual. In other words, the opening time of 1 second Q3 small increases as voltage increases. voltage stabilization: Use negative feedback resistors R4 voltage. Q3 widened If (as the high pressure), the flow across R4 increases. Pressure drop across R4 (in UR4 IQ3 = x R4) increased. To see the pressure drop is put on foot through R8 to Ub B Q4 Q4 increase of saturation Q4, Q3 lock earlier than usual. In other words, the opening time of 1 second smaller Q3 will decrease the output voltage to decrease. If Q3 small opening (making a low pressure), the reduced flow through R4. Pressure drop across R4 (in UR4 IQ3 = x R4) down. Notice will see this put pressure drop across R8 leg B Q4 to Q4 decreased Ub, Q4 will be saturated, Q3 later than usual lock. In other words, the opening time of 1 second Q3 small increases as voltage increases.

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