ATX power supply of knowledge

At present, ATX power supplies are widely used in computers, compared with the AT power supply, it is more in line with "green computer" energy-saving standards,
It corresponds to the motherboard is the ATX motherboard. It corresponds to the motherboard is the ATX motherboard.

1.ATX power characteristics of 1.ATX Power Characteristics

Compared with the AT power supply, ATX power supply increases "+3.3 V, +5 VSB, PS-ON" three outputs. Compared with the AT power supply, ATX power supply increases "+3.3 V, +5 VSB, PS-ON" three outputs. Which "+3.3 V" output is mainly for the CPU use, and "+5 VSB", "PS-ON" ATX power supply output is embodied characteristics. In which "+3.3 V" output is mainly for the CPU use, and "+5 VSB", "PS-ON" while the output reflects the ATX power supply features.


ATX Power Supply The main feature is that it does not use traditional electricity switch to control the power supply is working, instead of using "+5 VSB, ATX Power Supply The main feature is that it does not use traditional electricity switch to control the power supply is working , instead of using "+5 VSB,
PS-ON "to achieve a combination of the power supply turn on and off, as long as the control of" PS-ON "signal level changes, will be able to control the power of the opening and closing." PS-ON "is less than 1V when the open-volt power supply, large at 4.5 volts when you turn off the power. PS-ON "to achieve a combination of the power supply turn on and off, as long as the control of" PS-ON "signal-level changes, will be able to control the power of the opening and closing. "PS-ON" is less than 1V when the open-volt power supply, large at 4.5 volts when you turn off the power.

2.ATX the core of the power circuit 2.ATX the core of the power circuit

The main ATX power supply conversion circuit and AT power supply the same, but also a "twin-tube half-bridge is excited" circuit, PWM (pulse width modulation) controllers use the same control chip TL494, but the abolition of electricity switch. The main ATX power supply conversion circuit and AT power supply the same, but also a "twin-tube half-bridge is excited" circuit, PWM (pulse width modulation) controllers use the same control chip TL494, but the abolition of electricity switch.

As the abolition of the municipal electric switch, so long as connected to the power line, the conversion circuit there will be +300 V DC voltage, and auxiliary power is also to provide work to the TL494 voltage, the power to prepare for the launch. As the abolition of the municipal electric switch, so long as connected to the power line, the conversion circuit there will be +300 V DC voltage, and auxiliary power is also to provide work to the TL494 voltage, the power to prepare for the launch .

ATX power supply is characterized by the use of TL494 chip 4 feet of "dead drive control" function, when the pin voltage is +5 V when, TL494's first 9,11 feet no output pulse, so that the two are cut-off switch, power on standby state, no voltage output. ATX power supply is characterized by the use of TL494 chip 4 feet of "dead drive control" function, when the pin voltage is +5 V when, TL494's first 9,11 feet no output pulse, so that the two are cut-off switch , power on standby state, no voltage output. but when the first four feet of 0V when, TL494 have trigger pulse provided to the switch, power supply into a normal working condition. And when the first four feet of 0V when, TL494, there trigger pulse provided to the switch, power supply into a normal working condition. Auxiliary power supply all the way out to send TL494, another output by the divider circuit to be "+5 VSB" and "PS -ON "2-signal voltage, they are for the +5 V. Auxiliary power supply all the way out to send TL494, another output by the divider circuit to be "+5 VSB" and "PS-ON" 2-signal voltage, they are for the +5 V. One, "+5 VSB" output connectors ATX motherboard into a "power monitoring components", as its operating voltage, asked "+5 VSB" output can provide 10mA of operating current. One, "+5 VSB" output to connect to the ATX motherboard "Power control parts", as its operating voltage, asked "+5 VSB" output can provide 10mA of operating current. "Power control parts" of the output and "PS - ON "" Power control parts "of the output and" PS-ON "
Connected, in its trigger button switch (non-locking switch), when not pressed, "PS-ON" to +5 V, it is connected to a voltage comparator U1 positive phase input, and Connected, in its trigger button switch (non-locking switch), when not pressed, "PS-ON" to +5 V, it is connected to a voltage comparator U1 positive phase input, while the
U1 negative phase input voltage of about 4.5V, so that voltage comparator U1 input for +5 V, sent to the TL494's "death-drive control of the foot", so that ATX power supply in a standby state. U1 negative phase input voltage of about 4.5V, so that voltage comparator U1 input for +5 V, sent to the TL494's "death-drive control of the foot", so that ATX power supply in a standby state. When pressed motherboard Power Monitoring trigger button switch (mounted on the main chassis of the panel), "PS-ON" becomes low, then the voltage output of the comparator U1 is 0V, so that the host ATX power supply to open. When pressing the trigger button on the motherboard's power control switch (mounted on the main chassis of the panel), "PS-ON" becomes low, then the voltage output of the comparator U1 is 0V, so that host ATX power supply to open. then press the trigger button on a panel on the switch, so that "PS-ON" again becomes +5 V, and thus turn off the power. Then press the trigger button on a panel on the switch, so that "PS-ON" again becomes +5 V, and thus turn off the power. At the same time can also be used program to control the "power monitoring parts" of the output, so that "PS - ON "becomes +5 V, auto power off. At the same time can also be used program to control the "power monitoring parts" of the output, so that "PS-ON" becomes +5 V, auto power off. If WIN9X platforms, issue the shutdown command, ATX power supply on the shut down automatically. If WIN9X platforms, issue the shutdown command, ATX power supply is automatically shut down.

3. Motherboard can not power on failure analysis 3. Motherboard can not power on failure analysis

Since the opening subject to the motherboard ATX power supply control components, so when the host appeared unable to increase ATX power failure, the failure was not immediately determine the power itself or the motherboard's "power monitoring components", to bring to the maintenance difficult. Since the opening subject to the motherboard ATX power supply control components, so when the host appeared unable to increase ATX power failure, the failure was not immediately determine the power itself or the motherboard's "power monitoring components," has brought some difficulties to the maintenance .

Based on the above analysis, we can "PS-ON" output and the indirect manner about a 100 OHM resistor, so that "PS-ON" becomes low, you can start the ATX power supply, so you can distinguish between failure positions. Based on the above analysis, we can "PS-ON" output and the indirect manner about a 100 OHM resistor, so that "PS-ON" becomes low, you can start the ATX power supply, so you can distinguish between failure positions. also told us that, if the ATX motherboard "Power control parts" fails, because of its more difficult to repair, we can skip the "Power control components," direct control "PS-ON" voltage, can be open or Close the host. Also told us that, if the ATX motherboard "Power control parts" fails, because of its more difficult to repair, we can skip the "Power control components," direct control "PS-ON" voltage, can be open or Close the host . Of course, the host at this time there is no automatic shut-off function. Of course, the host at this time there is no automatic shut-off function.