App note: 1 kV SenseFET integrated power switch

App note from ON Semiconductors on their FSL4110LR power switch for SMPS power supplies. Link here (PDF) Some industrial equipment that are supplied from a threephase AC power source such as industrial drives and energy meters often need an auxiliary power supply stage that can provide a regulated low-power DC source for analog and digital […]

App note: Power supply topologies – Forward of Flyback? Which is Better? Both!

App note from Coilcraft camparing two recognized power supply topologies. Link here (PDF) Beatles or Stones? Michael or LeBron? Deep dish or thin crust? Forward or flyback? These are just a few of the age-old questions that have been hotly debated over the years, people arguing their opinions with great vigor. But, the truth is, […]

App note: How to eliminate over stress of MOSFET during start-up of flyback converter

App note from Richtek about their embedded soft-start function to eliminate MOSFET stress. Link here Switching Power Supply, compared to Linear Power Supply, is widely used due to its advantages, such as small size, light weight, high efficiency, etc. Flyback Converter, one of the switching power supply topologies, is most suitable for power supply systems […]

App note: The four benefits brought by using NCP12600

App note discussing extended features of NCP12600, NCP12600 is a multi-mode controller for offline power supplies by ON Semiconductor. Link here (PDF) Beside the novel multi−mode structure it embarks, the NCP12600 packs a lot of features such as an efficient short−circuit protection architecture, a start−up sequence with a slow switching frequency ramp−up, a fast reset […]

App note: TEA1938T GreenChip SMPS control IC

TEA1938T SMPS control IC application note from NXP Semiconductors. Link here (PDF) The TEA1938T is a high-featured low-cost DCM and QR mode flyback converter controller. It provides high efficiency at all power levels and very low no-load power consumption at nominal output voltage in burst mode operation. To minimize ripple, the burst mode uses a […]

App note: Audible noise reduction techniques for FPS (Fairchild Power Switch) Applications

Reducing audible noise in switch mode power supplies app note from ON Semiconductors. Link here (PDF) In general, switched mode power supplies do not generate audible noise when they operate at constant ultrasonic frequencies (>20kHz). However, some switched mode power supplies can produce audible noise at certain load conditions. Most Fairchild Power Switches are designed […]

Analysis, operation, and modification of a switchmode power supply (SMPS) for variable output voltage

Lindsay Wilson did a teardown/modification of a Chinese SMPS to allow an adjustable output voltage: I’m currently working on a product which uses a size 2430 “hobby” brushless motor and 25A electronic speed controller (ESC). In its “intended” use, the controller runs from two lithium-ion batteries with a total voltage of around 7.4V, but I […]

App note: Output capacitive load considerations

App note(PDF) from Murata on output capacitors loading when in a switch mode power supply There are numerous factors to consider when adding external capacitors to switched-mode power supplies (SMPS). This article will discuss noise, startup, ESR, stability, pre-bias applications, Sense inputs, On/Off (remote enable) controls and other topics. Many real-world DC/DC applications require external […]

App note: Switching power supply design with the PIC16F785

An SMPS application using PIC16F785 from Microchip, app note here (PDF). In this application note, we will examine a typical buck topology intelligent SMPS design using the PIC16F785. The design presented here shows an alternative single-chip approach to adding intelligence to SMPS designs. The basic design is really unchanged. There are current and voltage feedback […]

SMPS with battery backup and NiMH charger using the LM2595

Giorgos from PCBheaven designed an SMPS buck regulator with 2xAA NiMh battery trickle charger and power failure output: Some time ago I presented a small circuit with the MCP1640, the High Efficiency Battery Boost Regulator using the MCP1640. My original intention was to combine it with this one and make a complete power supply unit with […]

App note: Reducing system noise and voltage overshoot in buck topology switch mode regulators

Here is an article describing how to reduce noise and voltage overshoot in buck topology DC/DC converters. Slowing down the turn on time of the high side switch in conjunction with replacing a diode with a low side switch should increase efficiency and lower the power dissipation. Adding snubers (RC circuit) in parallel to the […]

App note: High power LED driver with PIC12F675

A current controlled buck converter for driving high-power LEDs. The PIC12F675 microcontroller has an integrated comparator, which in combination with a low pass filter provides a control circuit for the SMPS. The circuit is based on a buck topology switching power supply using the on-chip comparator peripheral within the PIC12F675 microcontroller. The switching power supply […]

Offline high voltage AC power supply

Dilshan designed an offline high voltage AC power supply primarily for SMPS testing. It outputs a square wave, so hooking it up to a mains-transformer based linear supplies is not a good idea, as the transformer will overheat. It’s open source hardware, so the schematics and design files are available. This is a high voltage, […]

App note: Minimizing switching regulator residue in linear regulator outputs

Here is an app note from Linear Technology describing how to minimize switching regulator noise in linear regulator outputs. Linear regulators are commonly employed to post-regulate switching regulator outputs. Benefi ts include improved stability, accuracy, transient response and lowered output impedance. Ideally, these performance gains would be accompanied by markedly reduced switching regulator generated ripple […]

App note: Switching regulators for poets

The basics of SMPS design, written by the late analog guru Jim Williams: A problem is that while everyone agrees that working switching regulators are a good thing, everyone also agrees that they are difficult to get working. Switching regulators, with their high efficiency and small size, are increasingly desirable as overall package sizes shrink. […]

Super Boost 3.6A USB charger based on LM2700

Scrawny 500mA USB charger insufficient for your hunger for power? Try this 3.6 amp USB charger based on the LM2700 boost switch-mode IC. This design is inspired by the Minty Boost but it fixes some of the issues that I had with it. The Minty Boost is limited to 600mA due to the LT1302 chip. […]

Bus Pirate PIC programmer update

PIC 12/16/18/ds30 programming support for the Bus Pirate is progressing. Sean Nelson, a regular contributor to the Bus Pirate project, submitted a patch that adds serial port support to usbpicprog. The Linux patch compiles, but the Windows port still has some bugs. The picture shows our prototype 13volt power supply for the PIC programmer. It’s […]