Knowledge

Every SMPS has an output rectifier, and every output rectifier is a choice between three technologies that hide different loss envelopes. A fast-recovery diode, a Schottky, and a synchronous-rectifier MOSFET can all be the “right” answer depending on the output voltage, the switching frequency, and the loss split of the specific converter. This article pairs … Read more

A switching power supply looks like a box of unrelated parts until you see the jobs. Five component types — the switch, the transformer, the rectifier diode, the output capacitor, and the controller — carry the whole conversion, and each one is a worker with a specific job whose failure has a specific signature. When … Read more

One trades heat for noise. That sentence is the whole story of linear versus switching power supplies, because every difference between the two topologies traces back to whether they convert the line power with a switching element or without one. A linear supply is simple, quiet, and inefficient — most of the wasted energy leaves … Read more

There are three ways to make a 5 V rail from a higher supply, and they are not equivalent. A Zener shunt is simple and cheap but wastes power as soon as the load is small; a linear LDO is cleaner but burns the same drop as heat; a buck DC-DC is efficient but adds … Read more

Every switch cycle in a flyback converter ends the same way: the switch turns off, the leakage energy in the transformer releases, and the output rectifier rings like a struck bell. The spike and the oscillation have a rhythm you can measure on a scope, and the snubber is the tuning that damps it. This … Read more

The gate oxide of a MOSFET is a door roughly 20 nanometers thick, and spikes and ringing can break it. A gate driven past its voltage limit, or hit by a fast dv/dt spike, fails the part in an instant — and the Zener clamp is the doorstop that holds the door. This article explains … Read more

Repairing a power supply is not a parts-drawer exercise; it is a sequence, and the sequence starts with safety. The order of actions — discharge, isolate, limit, test — is what separates a safe repair from a dangerous one and a quick diagnosis from a parts swap that fails again. This article builds the safety-first … Read more

A rectifier-based power stage fails in the field for a small set of reasons, and the reasons are nearly all visible before the board ships. The ten-check audit turns that knowledge into a release gate: ten questions, each with a pass criterion and a trace to the design method that answers it. This article presents … Read more

A single source is one fire away from stopping the line. A fire, a strike, a trade restriction, or a supplier’s own quality problem can all take a sole-sourced part off the market, and the board stops shipping with it. Second-sourcing turns that risk into a qualification flow: a defined set of gates that prove … Read more

The price advantage of buying discrete power parts from China is real, and so is the hidden cost of getting it wrong. The difference between a good purchase and a bad one is decided before the money moves: the five documents and the three tests that verify the supplier and the part. This article balances … Read more

A factory audit finds the real problems by following one part from the wafer to the box, because the failures appear at the hand-offs between the stages. The wafer that looked clean, the assembly that looked correct, and the test that looked complete can all be right on their own and still deliver a bad … Read more

A counterfeit semiconductor is usually bought for a reason that sounds sensible — a price below the market, a part in stock when nobody else has it — and the counterfeit is revealed by clues that are visible before the part ever powers up. The price gap, the packaging inconsistencies, and the electrical data all … Read more