The role of the ATX power supply is to convert the AC into the commonly used DC power supply. It has three outputs. Its output is mainly memory and VSB, and the output reflects the characteristics of ATX power supply. The main feature of ATX power supply is that it does not use the traditional power switch to control the power supply, but uses + 5 VSB to form a device with switches that alternate with each other. As long as the PS-signal level is controlled, it can be turned on and off. the power of. PS open when power is less than 1v, power supply greater than 4.5 volts should be turned off.
Compared with the power supply, the ATX power supply is not the same on the line, the main difference is that the ATX power supply itself is not complete when it is turned off, but maintains a relatively weak current. At the same time, it adds a feature that leverages the current power management, called Station Pass. It allows the operating system to manage direct power supply. Through this function, users can change the switch system by themselves, and can also realize the power of network management. For example, the computer can connect to the modem’s signal to the computer through the network, and then the control circuit will send out the unique ATX power + 5v activation voltage, start to turn on the computer, and thus realize the remote start.
The core circuit of ATX power supply:
The main conversion circuit of the ATX power supply is the same as that of the AT power supply. It also adopts the “double-tube half-bridge other excitation” circuit. The PWM (pulse width modulation) controller also uses the TL494 control chip, but the mains switch is cancelled.
Since the mains switch is cancelled, as long as the power cord is connected, there will be +300V DC voltage on the conversion circuit, and the auxiliary power supply also provides working voltage to the TL494 to prepare for the start-up power supply.
Post time: Jul-12-2022