According to the survey, there are many single and dual power supply chips on the market, and analog circuits are also one of their main applications. Then we can think about what the dual power supply of the chip means? What are his characteristics?

Most of the op amp circuits use ±15V typical power supply in consideration of circuit simplicity and signal accuracy. A small number of op amp circuits are powered by a single power supply, so when there are differences in the power supply (single and dual), how to choose an op amp chip and whether it can be substituted for each other is a problem that needs attention.

In fact, many chips currently support single and dual power supply operation, so there is no problem in most applications. One of the main applications of analog circuits is the front-end acquisition and processing of sensor signals, so there are still some applications for the characteristics of sensor signals. exquisite. The main characteristics of the sensor signal are as follows: the signal amplitude is generally small, the linearity is required to be high, and the noise suppression performance is required to be high.

Common Mode Voltage Input Range

This refers to the range of the chip‘s input voltage. What we call rail-to-rail output means that the chip‘s output voltage can reach the power supply, VCC or GND or VSS. In fact, it is only close at most, and it is impossible to fully reach the power supply value. That is to say, the swing, the swing simply determines the upper and lower limits of the chip output, and the common mode voltage input range refers to the upper and lower limits of the chip input. Then for a single power supply, the maximum input range of the common mode voltage is 0 to VCC, while for a dual power supply, the range is a large range of positive and negative.

Then the main features of single and dual power supply:

1. The cost of a single power supply is low, because there is no need to generate an additional negative power supply.

2. The detection range of the dual power supply is larger, especially for the signal input near the zero point such as several mv or even smaller, the single power supply may not be able to detect at all.

3. For the amplification of the AC signal, the bias of the dual power supply is at the zero point, while the static operating point of the single power supply is near one-half of the power supply, and an appropriate bias point needs to be set.

4. For output swing requirements, the scope of dual power supply is also larger.

5. The wider common-mode input range will have the effect of reducing noise and other performance (the reason is unclear).

Summary: The main purpose is to understand several differences between single and dual power supplies. If you encounter related problems, you may expand your thinking boundaries.