Patent ID: 11875873
Assignee: YANGTZE MEMORY TECHNOLOGIES CO., LTD.
Field: Computer technology (Electrical engineering)
Classification: CPC G | IPC G

Claim 0:
1. A circuit for multi-mode ZQ calibration, comprising:
a first resistor input connected between a first external resistor coupled to a ground voltage and a first group of pull-up drivers;
a second resistor input connected between a second external resistor coupled to a supply voltage and a first group of pull-down drivers;
a first comparator connected to the first resistor input, to the second resistor input, and to a first plurality of selectable voltages, and the first comparator is configured to:
generate a first pull-up signal based on a comparison between a first ZQ pad voltage at the first resistor input and a first one of the first plurality of selectable voltages; and
generate a first pull-down signal based on a comparison between a second ZQ pad voltage at the second resistor input and a second one of the plurality of selectable voltages;

a second comparator connected to a middle point between a second group of pull-down drivers and a second group of pull-up drivers, and configured to generate a second pull-up signal or a second pull-down signal based on a comparison between a voltage at the middle point and a third one of the plurality of selectable voltages;
a logic pull-up code generator configured to:
generate a first pull-up code based on the first pull-up signal to calibrate the first group of pull-up drivers, and
generate a second pull-up code based on the second pull-up signal to calibrate the second group of pull-up drivers; and

a logic pull-down code generator configured to:
generate a first pull-down code based on the first pull-down signal to calibrate the first group of pull-down drivers, and
generate a second pull-down code based on the second pull-down signal to calibrate the second group of pull-down drivers.