Pulse-width modulation (PWM), or pulse-duration modulation (PDM), is a commonly used technique for controlling power to inertial [ambiguous] electrical devices, made practical by modern electronic power switches. The average value of voltage (and current) fed to the load is controlled by turning the switch between supply and load on and off at a fast pace. The longer the switch is on compared to the off periods, the higher the power supplied to the load is.
Gideon Analytical Laboratories received a Printed Circuit Board (PCB) with contamination on several capacitor sleeves, connector pins, and an oscillator. An electrolytic capacitor is a capacitor whose anode (+) consists of pure aluminum foil with an etched surface, covered with a uniformly very thin barrier layer of insulating aluminum oxide, which operates as a dielectric. The electrolyte, which covers the rough surface of the oxide layer, operates as the second electrode, the cathode (-).
Gideon Analytical Laboratories received two valves with failed printed circuit boards (PCBs) and corrosion inside the housing. The goal was to determine what the corrosion was and why the PCB failed. A printed circuit board mechanically supports and electrically connects electronic components using conductive trace lines, pads and other features etched from copper sheets laminated onto a non-conductive substrate. The boards are made from glass reinforced plastic with copper tracks in the place of wires.
Gideon Analytical Laboratories received 8Murata Ps DC-DC converters (pn 8600118) with suspected MOSFET failures. A DC-DC converter is an electronic circuit or electromechanical device that converts a source of direct current (DC) from one voltage level to another. It is a type of electric power converter. Power levels range from very low (small batteries) to very high (high-voltage power transmission). The DC to DC converters MOSFET is a type of field-effect transistor (FET).
GideonAnalytical Laboratories received several Printed Circuit Boards (PCBs) that were experiencing delamination of the solder masks, specifically on the EMI filter card. A PCB mechanically supports and electrically connects electronic components using conductive tracks, pads and other features etched from copper sheets laminated onto a non-conductive substrate. Components (e.g. capacitors, resistors or active devices) are generally soldered on the PCB. Advanced PCBs may contain components embedded in the substrate. Electromagnetic interference (EMI), also called radio-frequency interference (RFI) when in the radio frequency spectrum, is a disturbance generated by an external source that affects an electrical circuit by electromagnetic induction, electrostatic coupling, or conduction.
The RS2042 is a low startup current, current mode PWM controller with Green-Power & burst-mode power-saving operation. It has integrated functions such as the leading-edge blanking of the current sensing, internal slope compensation, low external component counts, and easily fits in with AC/DC power applications. The Green-Power function provides off-time modulation to linearly decrease the switching frequency under light-load conditions. And under zero-load conditions, the power supply enters burst-mode to further reduce power consumption by shutting off PWM output.
Gideon Analytical Labs received pulse width modulators PWM failing in a MuRata Ps DC-DC converter. The PWM was removed from the encapsulation and tested. Several I/O pins were either open or showed no connection to the circuitry of the IC. The PWM CS51022AG is a fixed frequency current mode controller family provides the necessary features for DC−DC primary side control. In addition to low startup current (75A) and high frequency operation capability, the CS51022A includes over-voltage and under-voltage monitoring, externally programmable dual threshold over-current protection, current sense leading edge blanking, current slope compensation, accurate duty cycle control and an externally available 5.
