Http://www.cnblogs.com/crazybingo/archive/2010/05/14/1735802.html
Differences in C, VDD, VSS, VEE, and VPP
In electronic circuits, there are three different symbols for VCC, VDD, and VSS, and what is the difference between them?
First, explain
Vcc:c=circuit indicates the meaning of the circuit, that is, the voltage of the access circuit; Vdd:d=device indicates the meaning of the device, i.e. the operating voltage inside the device;
Vss:s=series denotes the meaning of a public connection, usually referred to as the circuit's common ground terminal voltage.
Ii. description
1, for the digital circuit, VCC is the power supply voltage of the circuit, VDD is the operating voltage of the chip (usually VCC>VDD), the VSS is the pick-up location.
2. Some ICS have both a VDD pin and a VCC pin, indicating that the device itself has a voltage conversion function.
3. In the presence effector (or COMs device), VDD is the drain, VSS is the source, and Vdd and VSS refer to the component pin, not the supply voltage.
Statement one:
VCC, VDD, VEE, and VSS refer to the Power aggregation point of the chip and the decomposition circuit, depending on the device material and the polarity of the power supply. VCC is generally referred to as a transistor C-pole connected directly to an integrated or decomposed circuit, and Vee is an e-pole connected to the internal transistor of an integrated or decomposed circuit. Similarly, VDD, VSS refers to the D and s poles of the FET that are connected to the internal, decomposed circuit. For example, an integration made using the P-Groove E/dmos process, then its VDD bell the power supply negative, while the VSS Bell positive power supply.
That's how they got their name:
VCC represents the power supply connected to the transistor collector (C).
Vee indicates the power supply connected to the transistor emitter (E).
VDD indicates the power supply of the drain (D) connected to the farm effect tube.
VSS represents the power supply that connects the source (S) of the farm effect tube.
Normally VCC and VDD are power supply, while Vee and VSS are either negative or ground.
Statement two:
VDD,VCC,VSS,VEE,VPP differences
VDD: Supply voltage (unipolar device), Supply voltage (4000 series digital circuit), drain voltage (field effect tube)
VCC: Supply voltage (bipolar device), supply voltage (74 series digital circuit), voice carrier (voice controlled Carrier)
VSS: Ground or power negative
VEE: Negative voltage supply, field effect tube source (S)
VPP: Programming/erasing voltage
Category: Electronic Design
Differences in C, VDD, VSS, VEE, and VPP