The operating principle of the Intel dual-bridge G41 chipset motherboard boot circuit.

Intel G41 chip group motherboard boot circuit consists of RTC, South Bridge chip, IO chip, switch pin, ATX power interface, as shown in figure 1, under the assistance of IO chip and South Bridge chip to complete the motherboard start-up function, the working principle is as follows.

 Fig. 1 Working principle block diagram of IntelG412 chipset motherboard boot circuit.

The first stage: install the battery, through the resistance R427 and diode D26 to generate VBAT real-time clock power to the South Bridge core line, and then through the JCMOS jumper cap to get the RTC_RST# real-time clock reset signal to the South Bridge chip. The South Bridge chip supplies the vibration power to the 32.768kHz, and the crystal oscillator generates the 32.768kHz frequency back to the South Bridge chip. At this time, the South Bridge chip real-time clock circuit begins to work, which is used to save the CMOS settings.

The second stage: plug in the power output 5VSB power supply, after the step-down circuit converted to 3VSB to supply the South Bridge chip, 3VSB to the F71882FG 68-pin power supply. The F71882FG sends out RSMRST# high level from 85 pins to the South Bridge chip to indicate standby voltage is normal and the standby work is completed.

The third stage: the short switch generates the PWSIN# trigger signal to the 80 pin of the F71882FG, outputs an 3.3V-0V-3.3V voltage jump PSOUT# signal from the 81 pin through the internal logic conversion, and sends the PSOUT# signal to the South Bridge chip to request power up. The South Bridge chip receives this signal, and when its standby condition is normal, the internal conversion output lasts 3.3V of the SLP_S3 # signal to the 82 pins of the F71882FG, indicating that power is allowed. The F71882FG receives the internal conversion of the SLP_S3# signal and outputs the PS ON# continuous low level signal from 83 pins to pull the low power green cable to complete the power up.

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