Active Directory to authenticate user access to Postgres DB through ODBC driver. Is this possible?
Active Directory has 3 kinds of authentication: NTLM (NT LAN Manager), Kerberos (GSSAPI), and LDAP. Active Directory is essentially a fancy LDAP server with extra authentication mechansims

LDAP is centralized authentication, but not single sign-on. Your password is the same as when you login to your computer, but you need to login to the database again

NTLM is single sign-on, but only works on Windows. PostgreSQL supports it via SSPI

Kerberos is also single sign-on, but works with Windows and UNIX/Linux/Mac too. You login to your computer, get a Kerberos ticket, and Postgres uses this ticket to authenticate you. Postgres needs to be setup as Service Principal in Active Directory

I would say that Kerberos or SSPI is what you want. 

Start with https://www.postgresql.org/docs/current/static/auth-methods.html