Webinars for Young Excellence: Interpolation: Creating a reference free smooth A/D conversion

Title: Webinars for Young Excellence: Interpolation: Creating a reference free smooth A/D conversion

Presenter: Prof. Akira Matsuzawa

Abstract: Conventional A/D conversion is performed by comparing the input signal voltage with the reference voltage. On the other hand, by dividing and comparing the output voltages of two amplifiers with different reference voltages with the same input signal voltage, it was found that A/D conversion can be performed. This A/D conversion method is called interpolated A/D conversion.

This conversion method enables smooth A/D conversion with a small DNL without adjusting the gain of the amplifier or the reference voltage, and also enables low power consumption by reducing the number of amplifiers.

In this talk, we will introduce not only the principles and effects of interpolated A/D conversion, but also conceptual methods in circuit development, such as generalization by intuition and formulation that gave rise to unique A/D conversion methods.

A resistive-interpolated Bi-CMOS ADC was developed for home HDTV receivers. A capacitive-interpolated CMOS ADC reduced the power consumption to 1/8 of other ADCs was developed for the portable digital video equipment such as a handy camcorder. A gate-width interpolation CMOS ADC achieved ultra-high-speed operation of 400 MS/s and 1/10 the power consumption of the other ADCs. It is embedded on the world’s first one-chip Mixed Signal SoC for DVD and contributed higher performance and lower cost of DVD recorders.

In this talk, we would like you to understand that the interpolated A/D conversion method is not just an idea but was created for the development of A/D converters with high performance and low power in order to realize the new electronic devices.

Akira Matsuzawa received B.S., M.S., and Ph.D. degrees in EE from Tohoku University, Sendai, Japan, in 1976, 1978, and 1997. In 1978, he joined Panasonic, and in 2003, joined Tokyo Institute of Technology as a full professor, and in 2018, became professor emeritus and CEO of Tech Idea. He has been developing video-rate ADCs, mixed-signal SoCs and millimeter-wave CMOS transceivers. In 2022, he received IEEE Donald. O. Pederson award in Solid-State Circuits. He is an IEEE Fellow since 2002 and Life-Fellow since 2023.