I see you like to study. I'll send you some information.
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VCC-- C=circuit, meaning line, refers to the positive end of the power input connected to a complete circuit. Indicates the DC voltage. Main supply voltage or general supply voltage on the main board. For example, the general circuit VCC3- 3V power supply.
Vcc3: 3.3v vcc25: 2.5v vcc333: 3.3v vcc5: 5v vcc12: 12v
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VCORE: CPU core voltage (depending on CPU OR voltage fixture)
VDD-- D=device, should be said to be connected to the meaning of the component, such as: refers to the working voltage of an IC, does not exclude some IC at the same time connected to VCC, VDD. It's just a general term. Ordinary IC power supply, may be 3V, 1.5V, such as digital circuit positive voltage, gate circuit power supply, etc.
VDDQ- need to be filtered power supply, stability requirements are higher than VDD,
VSS- ground, negative power terminal, common point, S=series, refers to the negative terminal of the power supply, generally 0 volts or voltage reference point
GND-- ground
VEE:... Ibid. It all means \"ground\".
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The supply voltage is generally marked as Vdd,Vcc
VID- Indicates the CPU voltage identification signal. Previous old motherboards have VID jumpers, now generally do not, CUP operating voltage is defined by VID. By controlling the power supply IC output rated voltage to the CPU.
VTT- is the AGTL bus terminal voltage (VTT1.5V, VTT2.5V), for different types of CPU there are 1.8V, 1.5V, 1.125V. The measuring point is next to the cpu socket, and there's a lot of 56 rejection. That's it.
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CS-- Film selection
CAS- Row strobe
RAS-- column strobe
RESET- reset
CLK- Clock
SCLK- Serial clock
A or SA- Address line
SYNC- Serial synchronization
SDATA- Serial data
VDIMM- The power supply for the memory slot.
5VSB- 5V standby power supply, standby power refers to the computer is not turned on, but plugged into the external power supply, there is a part of the motherboard is powered, can do wake-up and other functions of electricity, SB=stand by- standby.
3VSB- 3V standby power supply
主板有5vsb, 3vsb, 3v, 5v, 12v, 5v_dual (usb)。
Power_ok或power_good: 3.3v或5v
There is also this understanding, VDD, connected to the D pole, that is, the drain pole; VSS, connected to the S pole, that is, the source pole, there are too many CMOS devices in the IC on the mainboard. VCC, connected to the triode's C pole, collector. VEE, the E pole to the triode, the emitter anyway, we just need to know which is positive and which is negative. In some rare circuits (devices), the opposite will be encountered, which is not what we need to understand.
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Vpp: Voltage absolute amplitude (V), for example, the textbook talked about sine wave, positive half and negative half of the voltage absolute size, with the oscilloscope to see the motherboard cpu voltage tube waveform, we see the square wave is not very standard square wave, it has 12V in the positive direction (for example), in the negative direction, there will be 0.5V space (estimated to be artificially retained), So Vpp is equal to 12.5V.
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Vp: Peak voltage, multimeter is not out, oscilloscope can, such as clock waveform, refers to the voltage value of the waveform vertex.
If there is a standard, Vpp = Vp, if it is a square wave in a continuous positive and negative direction, Vpp = 2*Vp.
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Vref: Voltage reference, also known as the reference voltage. It does two things,
1, digital circuit, is used for logic reference, such as cpu, chipset, memory, etc. have Vref introduction, rely on it to refer to determine whether the signal voltage is high or low level.
2, analog control of some functions, I\/O to the motherboard voltage monitoring, on the reference point.
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The difference between ALW, SUS and RUN
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A lot of people in the repair of the laptop, always be inside the voltage can not be turned, especially the voltage code inside, such as: are 3V voltage, there are many names, so beginners do not know, here I take Dell computer as an example, the system to explain to you:
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On the Dell computer motherboard, most circuit diagrams have ALW, SUS, Run, etc., to give you an example, 3VALW, 5VALW, 3VSUS, 5VSUS, 3VRUN, 1_8vRUN, 5VRUN, etc., many beginners are a little strange to these titles, more easily confused, This is not conducive to understanding the circuit, more conducive to improving the analysis of the circuit, so I want to sweep away this obstacle for beginners.
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In fact, the computer is mainly studied by foreigners, so these code names inside are just English abbreviations, we only have an understanding of the English, or not too difficult. First of all, ALW, its English full name is Alway, meaning always, it is probably expressed that when the power is plugged in, this voltage should have, so we plug in the power, only ALW, whether it is 3VALW, or 5VALW, as long as it is ALW, it should have its corresponding voltage, there is no system will not be powered on.
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The second is SUS, whose full English name is Suspend, meaning delay. Its voltage is produced behind the actual ALW voltage, and after receiving the SUS_on control voltage, this series of voltages will be produced. This voltage is not the main supply voltage, but only provides the foundation for the next voltage generation, but it does not mean that this voltage is not important, and there is no SUS voltage. The voltage behind it will not be generated.
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The second is RUN voltage, RUN voltage does not have an abbreviation, its meaning is the meaning of running, running, this is the main voltage of the north-south bridge work, of course, the north-south bridge also needs SUS voltage. If the system really runs, it needs the RUN voltage to be normal, and if the RUN voltage is unstable, it will cause the instability of the motherboard. Therefore, these voltages are gradual and interdependent, and the division of labor is different. Only by understanding their differences can we correctly analyze the circuit. Here I give a phenomenon that everyone is familiar with. We are all familiar with sleep, which turns off the operation of the system and saves the system information. The analysis of the power line is to turn off the RUN voltage, so that the main chips such as the North-South bridge stop working, but the SUS voltage is still saved, so that the system information is saved in the memory. The specific realization process of the circuit is to turn off the SLP signal. The I\/O does not send RUN_on signals, so that no Run voltage is generated, which can save power and save system information.