Bias voltage control for an output driver

摘要

An embodiment of an apparatus is disclosed. For this embodiment, an output driver and a bias voltage controller are included. The bias voltage controller is coupled to provide first and second bias voltages to the output driver. The bias voltage controller comprises a bias generator coupled to a first voltage supply, a second voltage supply, and a ground node. The bias generator has a first bias node for sourcing the first bias voltage. The first voltage supply is configured to provide a higher voltage level than the second voltage supply. A resistor-divider network is coupled to the first voltage supply and the ground node. A watch dog circuit is coupled to the resistor-divider network, bias generator, and the ground node. A comparison circuit is coupled to the bias generator and the second voltage supply. The comparison circuit has a second bias node for sourcing the second bias voltage.

主权项

1. An apparatus, comprising:
an output driver; and a bias voltage controller coupled to provide a first bias voltage and a second bias voltage to the output driver; wherein the bias voltage controller comprises:
a bias generator coupled to a first voltage supply, a second voltage supply, and a ground node;wherein the bias generator has a first bias node for sourcing the first bias voltage;wherein the first voltage supply is configured to provide a higher voltage level than the second voltage supply;a resistor-divider network coupled to the first voltage supply and the ground node;a watch dog circuit coupled to the resistor-divider network, bias generator, and the ground node; anda comparison circuit coupled to the bias generator and the second voltage supply;wherein the comparison circuit has a second bias node for sourcing the second bias voltage;wherein the watch dog circuit is configured to detect when the second voltage supply is below a voltage level to electrically couple the first bias node to the ground node; andwherein the watch dog circuit is configured to detect when the second voltage supply is above the voltage level to electrically decouple the first bias node from the ground node.