Mohammad Al-Shyoukh

A high-voltage level shifter with sub-nano-second propagation delay for switching power converters

A level-shifting circuit with sub-nano-second propagation delay for high input voltage switched-mode power converters is presented. The proposed circuit uses isolated low-voltage NMOS transistors and capacitive coupling to shift the control signal of the high-side power switch from a low-voltage logic domain (VLogic ~ 5V) up to a high-voltage power domain (VIN ~ 65V) with less than 115ps propagation delay. As a result, the non-overlap time inserted between the control signals of the high-side and low-side power switches can be minimized, leading to higher efficiency. Moreover, the control signal is shifted to the high-voltage power domain without reducing its voltage swing, which helps minimizing the on-resistance of the switch and further improves efficiency. The proposed circuit is fully integrated in a 0.18μm technology with no off-chip components. It occupies less than 0.75mm2 and provides built-in protection for the low-voltage devices with no additional protection circuitry. Transistor level simulations demonstrate the circuits functionality and performance.

A 500nA quiescent current, trim-free, ±1.75% absolute accuracy, CMOS-only voltage reference based on anti-doped N-channel MOSFETs

In this paper, an ultra low power CMOS-only voltage reference is presented. The reference exploits the work function difference between anti-doped (flipped-gate) and standard-doped nMOS devices. These devices require no additional processing and are realizable from the basic N+ and P+ implants used to implement the standard enhancement mode MOS devices on the process. The reference is implemented as a temperature-compensated ΔVgs between anti-doped and standard-doped nMOS devices. Integrated on 0.18μm CMOS, the reference occupies less than 0.04mm2 on silicon, requires less than 500nA of quiescent current, and has a trim-free accuracy of ±1.75% which is comparable to that of the most well-behaved voltage references employing BJTs.

A fully-integrated, 90% peak efficiency, 0.99 power factor, AC-DC LED Driver with on-chip direct-AC-connect series startup pre-regulator

In this paper, a fully-integrated AC-DC flyback converter for LED lighting applications is demonstrated. With the exception of passives, magnetics and rectification diodes, the entire AC-DC power converter including the ultra high voltage (UHV) power FET, control loop, current sensing, and startup functions have been integrated on the same monolithic bulk-CMOS silicon die. The startup function employs an 800 V depletion-mode pass device as part of a direct-AC-connect self-biased series pre-regulator. The entire AC-DC converter occupies an active area of 12.7 mm2 on silicon, and has a peak efficiency of 90% for a 15 W LED load. A control loop architecture employing critical conduction mode (CrM) with line voltage feed-forward enables near-unity power factor performance.