The working principle of the reset circuit for the AMD A55 chipset motherboard.

Last Update Time: 2019-11-20 15:07:03

         The reset principle of the AMD single bridge A 55 chipset motherboard is shown in figure 1.

         The reset principle of AMD single-bridge motherboard is not much different from that of double-bridge motherboard, but the signal name is different.

1. After the mainboard is turned on, the circuit depressurizes by memory power, CPU power supply, bridge power supply and bus power supply.

2. Clock circuits are integrated inside the bridge, which provides clock signals to each device on the motherboard.

3. The bridge power supply and the front panel reset switch are sent to the bridge via a FCH_PWRGD signal generated with the gate circuit, indicating that the motherboard power supply is normal.

4. After the bridge receives the power supply good signal, sends the APU_ PG signal to the CPU, to indicate the main board power supply is normal.


Fig. 1 AMD single bridge A 55 chipset reset principle block diagram.

5. Bridge internal logic circuit conversion output A_RST# signal reset IO chip.

6. The bridge generates PCIRST# signal reset PCI slot, PCIE _ RST# signal reset Nic chip and PCLE slot.

7. The bridge finally sends out a APU RST# signal to reset the APU.

   The FCH_PWRGD generation circuit is shown in figure 2. The VCCIP 1 bridge power supply is sent to the B pole of the Q58 via the resistor R346 so that the Q58 is switched on and the Q59 is cut off. After the ATX power supply is stabilized, the 5V high level output of ATX _ PWROK is send to the negative pole of D24 so that the D24 is cut off. The 3.3V high level of FP _ RST reset switch is send to the negative pole of D23 to make the D23 cut off. The short switch rear bridge chip emits 3.3V SLP S3# high level to the negative pole of D22, making D22 cut off. VCCIPI, ATX_ PWROK,FP_RST#, SLP_S3# through circuit phase and conversion. The 3.3V FCH_PWRGD_R signal from the R364 is sent to the bridge, indicating that the motherboard is powered normally.



Fig. 2 FCH_PWRGD generating circuit.

      If you want to know more, our website has product specifications for the working principle of the reset circuit for the AMD A55 chipset motherboard, you can go to ALLICDATA ELECTRONICS LIMITED to get more information