an-582_figure_6.py

import argparse


def figure_6_v_o(n: int, d: int, d_3: int) -> float:
    """
    Voltage divider calculation based on the approach shown in Figure 6.

    Args:
        n (int): The resolution of the RDACs in bits.
        d (int): The data bits of `U_1` and `U_2`.
        d_3 (int): The data bits of `U_3`.

    Returns:
        float: The calculated output voltage ratio. Note that `V_A` is factored out.
    """
    assert 0 < n
    assert d < 2**n
    assert d_3 < 2**n

    coarse = (d / 2**n) * ((2**n + 1) / (2**n + 2))
    fine = (d_3 / 2**n) * (1 / (2**n + 2))

    return coarse + fine


def main(v_a: float, r_ab: float, n: int):
    r_p = r_ab / 2**n
    result = sorted(
        [
            {"d": d, "d_3": d_3, "v_o": v_a * figure_6_v_o(n, d, d_3)}
            for d in range(256)
            for d_3 in range(256)
        ],
        key=lambda d: d["v_o"],
    )

    print(f"r_p: {r_p}")
    print(
        "["
        + ",\n ".join([str(d) for d in result[:10]])
        + "\n ...\n "
        + ",\n ".join([str(d) for d in result[-10:]])
        + "]"
    )


if __name__ == "__main__":
    parser = argparse.ArgumentParser(
        description="Voltage divider calculation based on the approach shown in Figure 6.\nhttps://www.analog.com/media/en/technical-documentation/application-notes/an-582.pdf",
        formatter_class=argparse.RawDescriptionHelpFormatter,
    )
    parser.add_argument("--v_a", type=float, required=True, help="The supply voltage.")
    parser.add_argument(
        "--r_ab", type=float, required=True, help="The resistance of the RDACs in ohms."
    )
    parser.add_argument(
        "--n", type=int, required=True, help="The resolution of the RDACs in bits."
    )

    args = parser.parse_args()
    main(args.v_a, args.r_ab, args.n)