This document discusses different techniques for driving large capacitive loads: 1. Cascading inverters as drivers, with an optimal fan-out of 3 inverters for a 1um technology. 2. Super buffers, which use an inverting buffer with 4 transistors and a non-inverting buffer to quickly charge and discharge large loads. 3.
Capacitors draw large currents from the power source at start-up, which can lead to tripping of the power source due to overload. To limit the inrush current into capacitors, power switches implement constant current charging of capacitors at start-up. To charge the capacitors with inrush current, the output voltage is increased linearly with time.
At power up, the output capacitor has zero voltage and there is power dissipation of (VIN X IINRUSH). As the capacitor gets charged, the voltage drop across the power device and the power dissipation decreases.
By influencing reactive power and power factor, capacitive loads can cause voltage fluctuations and instability if not properly managed. However, voltage regulation can be effectively maintained with the use of capacitor banks and power factor correction methods. Capacitive loads have both advantages and disadvantages in electrical systems.
Capacitive loads store electrical energy in a capacitor and release it back into the circuit. Unlike resistive loads or inductive loads, CLs have the characteristic of the current reaching its peak before the voltage does.
A discharged capacitor placed at the output of the converter will appear as a low impedance load. With this low output impedance, a few switching cycles of the converter can cause a change in voltage across the capacitor high enough to force the converter to exceed its output current rating.