Active Diode of 100 Hz-4 MHz-Span With Bias-Free Analog Control Circuit

We present an all-CMOS all-purpose active diode (AD) with the unique feature of a bias-free control circuit providing MHz-range of switching frequency. Current flow in the analog controller is limited to the switching transitions. MOSFET-switch of the AD is dynamically turned on/off based on the diode voltage-polarity sensed by the discrete conduction of the respective sensing-MOSFET, resulting in inherently no offset issue. No-overlap-drive by the complementary MOSFETs of the switch-driver, causes even a low reverse voltage across the AD to trigger a regenerative feedback for its fast turn off. ADs of different specifications were designed, fabricated, and tested in 180 nm CMOS technology. Bias-free operation provides an overall AD-efficiency of approximate to 97.0 % even with respect to sub-mW power level (approximate to 500 mu W ). While AD-switching transition time as low as 10 ns preserves the same efficiency till 500 kHz of switching frequency, it also gives efficiencies of 95.5% at 1 MHz and 85.3% at 4 MHz.