Off chip driver (OCD) with variable drive capability for noise control

摘要

An Off Chip Driver (OCD) having a high, a low and a high impedance (Hi-Z) state. The OCD includes an up-level pre-drive, a down-level pre-drive and a driver. The driver mirrors current in the up-level pre-drive and down-level pre-drive. Both pre-drive circuits have an unbalanced input-dependant delay to quickly turn off/on the on and off driver devices and, after a delay, reduce the drive on the turned on device to a steady state level. The delay may have a fixed length set by an inverter chain or may be dependent upon output voltage.