Calibration schemes for charge-recycling stacked voltage domains

A method of calibrating a mid-voltage node between first and second voltage domains in an integrated circuit including an input-output circuit having charge-recycling stacked voltage domains, the integrated circuit further including a supply voltage for the charge-recycling stacked voltage domains and a ground voltage, and wherein said first and second voltage domains are located in series between said supply voltage and said ground, the method comprising:

• transmitting data through the input-output circuit, including transmitting a first portion of the data across the first voltage domain, and transmitting a second portion of the data across the second voltage domain;
• measuring a specified characteristic of the data transmitted through the input-output circuit;
• and
• based on the measured specified characteristic, adjusting a voltage of said mid-voltage node to a defined value.

A method of calibrating a mid-voltage node in an integrated circuit having charge-recycling stacked voltage domains including at least first and second voltage domains, the method comprising:

• transmitting data across the first and second voltage domains;
• adjusting a voltage of said mid-voltage node to a defined value to obtain voltage drops across the first and second voltage domains;
• and wherein:
• each of the voltage domains includes a plurality of transmit drivers having variable strengths;
• and
• the adjusting the voltage of the mid-voltage node includes adjusting the strength of at least one of the transmit drivers of one of the voltage domains to adjust the voltage of the mid-voltage node to said defined value.