Hi @lingeshwar35845
First check that there's 19.5V DC at the output plug of the charger, to prove that it is working OK.
If the charger is OK then there may be a problem with the DC-In jack in the laptop.
What can happens sometimes is that the +ve centre pin of the jack, breaks internally and this opens the path for the charger to run the laptop and charge the battery.
To check if it is OK or not, here's the [https://dl.dell.com/topicspdf/latitude-e7270-ultrabook_owners-manual_en-us.pdf|owner manual] for the laptop.
Go to p.21 to view the procedure to remove the power connector port (aka DC-In jack).
Initially you only have to gain access to it so that you can disconnect the jack cable from the motherboard and then use either an Ohmmeter or a Voltmeter to prove continuity of the connection from the input side to the output cable plug end of the jack.
''If the DC-In jack is faulty'' it cannot be repaired, it has to be replaced.
Search online for ''VCYYW'' to find suppliers that suit you best.
''If the DC-In jack tests OK'' then there's a problem on the motherboard and further testing using the schematics for the motherboard would be required to find out what's wrong.