Patent Number: 6,295,233

Title: Current controlled open-drain output driver

Abstract: New methods and circuits for implementing current controlled open-drain output drivers are introduced. The present invention can be incorporated into a number of digital devices which utilize output drivers including, for example, high bandwidth DRAMs. In an exemplary embodiment, the present invention includes an on-chip current control circuit, a current control register, a switching controller, and a number of binary-weighted transistors arranged in a parallel configuration, all of which are implemented on an integrated circuit chip. The current control circuit continually generates a digital code which is periodically recorded by the current control register. The current control register then passes the digital code to the switching controller. Using the digital code, the switching controller, in turn, activates or deactivates the appropriate binary-weighted transistors accordingly thereby maintaining a relatively stable output current for the output driver.

Inventors: Kim; Y. H. (KyoungSanBuk-Do, KR), Ku; Ki Bong (KyungKi-Do, KR)

Assignee: Hynix Semiconductor

International Classification: G11C 11/4096 (20060101); G11C 11/409 (20060101); G11C 7/10 (20060101); G11C 007/00 ()

Expiration Date: 09/25/2018