Memristor-Based Reconfigurable True Time Delay Circuit

A memristor-controlled CMOS reconfigurable true time delay circuit is introduced in this paper. The delay circuit includes three stages of g(m)-C all-pass filter delay elements connected in cascade and memristor-based tunable DC voltage sources. The memristor value variation changes the DC bias voltage inputs of the delay elements and thus controls the delay time indirectly: The memristor resistance changes in analogue from 10 to 17 k Omega, changing the tunable DC voltage source output from 584- to 711-mV DC voltage and the delay from 269 to 632 ps. The delay circuit can work in a frequency range from 50 MHz to 1.6 GHz with gain ripple smaller than 3 dB. The resolvable delay time step across the delay range is < 8.7 ps, troughing at as low as 0.4 ps. A delay circuit working in the MHz region is also designed to compare the performance with the GHz circuit, and a memristor-programming circuit is built to change the resistance levels of memristors.