Circuit diagrams and schematics - Electronic projects

System designers must consider the timing and voltage differences between core and I/O power supplies (in other words, power-supply sequencing) during power-up and power-down. The possibility of a latch-up failure or excessive current draw exists when power-supply sequencing does not occur properly. The trigger for latch-up may occur if power supplies apply different potentials to [...]

The UCC3580 (www.ti.com), IC1 in Figure 1, is an active-clamp/reset-PWM IC that has all the requisites of a power-supply IC except for current limit. You can use the shutdown pin (16) for this purpose (see the UCC3580 data sheet). But when the shutdown pin activates, the soft-start capacitor normally connected to Pin 15 discharges, and [...]

T1 steps down AC voltage from 115VAC (or 220VAC) to about 8VAC and is then rectified via bridge rectifier BR1 to about 11.52Vdc. C1 filters off the AC ripple. If you find the circuit output too noisy add another electrolytic capacitor over the output terminals. Value can be between 10 and 100uF/25V. The output voltage [...]