How to reduce the falling and rising edges of the 393 comparator output

chuzhaonan

How to reduce the falling and rising edges of the 393 comparator output [Copy link]

How to reduce the falling and rising edges of the 393 comparator output?

maychang

The comparator has an open collector output. The rising edge of the output waveform is mainly determined by the pull-up resistor R7 and the subsequent input capacitor. If the subsequent input capacitor cannot be changed, the only way to reduce the output rising edge time is to reduce the value of the pull-up resistor R7. It is difficult to reduce the falling edge time of the output waveform.

maychang

LM393 is a very old chip with a relatively slow speed. If you want to reduce the falling edge of the comparator output pulse, you can only use a faster comparator chip, such as LM311. Of course, there are faster comparator chips now, but they are more expensive.

chunyang

What circuit is connected to the next stage? What is the significance of introducing R8? If there is a capacitive link in the next stage, R8 will only further deteriorate the edge characteristics. Removing R8 and reducing R7 at the same time can give full play to the characteristics of the device itself. If it is faster, it will only be replaced with a high-speed comparator.