I am tring to build half bridge using IR21844 mosfet driver, i have read datasheet and design tips and some of the topics in this forum. The one thing i still cannot get is the separate GND pins between logic and power.
I Qoute from an article:"The IR21844 has two different grounds, one for logic and one for power. Hypothetically, they are allowed to float 5 volts apart, providing some semblance of isolation between logic and power."
I have also confirmed this by looking into deisgn tip 97-3 page 2 paragraph 4 called Vs undershoot.
Design tip 97-3
I get that the 2 pins Vss and Com are should be connected ( becuase this is a non isolated driver) but how and where ?
My proposal now to is not to connect them at the PCB under the IC instead connect the Vss pin to micro controller logic GND and Com pin to lower Mosfet Source and let the 2 GNDs meet at the battery.
I am attaching my sample circuit schematic which is simplified to the maximum to show only the necessary items please provide your insight and correct me if i am wrong.
I also have doubt if a capacitor should be required between pin 7 (15v) and pin 3 (Vss) as the datasheet show but doesnot explain.
thanks in advance