Negative voltage generation circuit diagram

Needless to say, I need to explain the usefulness of positive voltage. In electronic circuits, we often need to use negative voltage. For example, when we use an op amp, we often need to establish a negative voltage for it. Let’s briefly talk about his circuit using a positive voltage of 5V to a negative voltage of 5V as an example.

Usually when I need to use negative voltage, I usually choose to use a dedicated negative voltage generating chip, but these chips are relatively expensive, such as ICL7600, LT1054, etc. Oh, I almost forgot about MC34063. This chip is used the most. I won’t mention the negative voltage generating circuit of 34063 here, it is in the datasheet. Let’s take a look at the two negative voltage generating circuits we commonly use in microcontroller electronic circuits.

Many of today's microcontrollers are equipped with PWM output. When we use microcontrollers, PWM is often not used. It is a good choice to use it to assist in generating negative pressure.

The above circuit is the simplest negative voltage generating circuit. The original components he uses are the least. We only need to provide him with a square wave of about 1kHz, which is quite simple. It should be noted here that the load generation capability of this circuit is very weak, and at the same time, the voltage drop is relatively large after adding a load.

Due to the above reasons, the following circuit was produced.