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Power Supplies:  DC to DC / Switch Mode and DC to DC Converters
Boost,    Buck,    Buck-Boost,    Switchmode

Power Supplies -- Main Page           Converters -- Main Page
DC to DC:  #'s - A       B - D       E - L       M - R       S - Z

Last Updated: October 24, 2017 02:55 PM

Circuits Designed by Dave Johnson, P.E. :

Medium Power 125khz Oscillator - This circuit adds even more inverters in parallel to deliver yet more power.  The values shown are for 125KHz. . . Circuit by Dave Johnson P.E.-March, 2002

 Medium Power 125khz Oscillator #2 - This circuit is similar to MEDIUM POWER 125KHZ OSCILLATOR but adds even more inverters in parallel to deliver yet more power.  The values shown are for 125KHz.. . . Circuit by David A. Johnson P.E.-March, 2002

 Micro Power Over-Temperature Alarm - The circuit is powered for years by a single 3 volt lithium battery.  It sounds an alarm when the temperature exceeds a certain point.  With some minor changes the circuit could also be configured for an under temperature (freeze) alarm.  The circuit uses a. . . Circuit by David Johnson P.E.-June, 2000

 Negative 0.5 Volt Supply - This simple circuit consists of two LEDs and a photo diode.  It generates a negative voltage with a current level of a couple milliamps.  It is ideal for supplying a negative rail to low power “rail to rail” op amp circuits, which need to have a true zero volts output.  Note:  This circuit is not particularly efficient . . . Hobby Circuit designed by David Johnson P.E.-July, 2006

 Over-Temperature Micro-Power Alarm - The circuit is powered for years by a single 3 volt lithium battery.  It sounds an alarm when the temperature exceeds a certain point.  With some minor changes the circuit could also be configured for an under temperature (freeze) alarm.  The circuit uses a . . . Hobby Circuit designed by Dave Johnson P.E.-June, 2000

 Peak to Peak 300v Signal Generator - This circuit converts a square wave signal to a +-150 volt output signal with fast 100nS rise and fall times . . . Hobby Circuit designed by David A. Johnson P.E.-June, 2000

 RS-232 Serial Interface Status Indicator Circuit - I designed this circuit many years ago and have used it several times since.  It uses a single logic IC to indicate the TXD and RXD line activity of a typical RS-232 serial data communications link.  The thresholds are set at plus 3 volts and minus 3 volts.  Two dual color LEDs are used as indicator lights . . . Hobby Circuit designed by Dave Johnson P.E.-December, 2007

Links to electronic circuits, electronic schematics, designs for engineers, hobbyists, students & inventors:

Power Supply-Basic UPS -  This circuit is a simple form of the commercial UPS, the circuit provides a constant regulated 5 Volt output and an unregulated 12 Volt supply.  in the event of electrical supply line failure the battery takes over, with __ Designed by Andy Collinson

Power switch provides soft start -  03/30/00 EDN Design Ideas:  in the circuit in Figure 1, series-connected MOSFETs turn on the line voltage near the zero-crossing point and off when the 555-timer delay lapses.  That delay ranges from 1 to 7 msec.  The MOSFETs’ body diodes and the 1N4005 diodes form a full-wave bridge rectifier __ Circuit Design by John Haase, Colorado State University, Fort Collins, CO

Powerful AM Transmitter -  The circuit for a powerful AM transmitter using ceramic resonator/filter of 3.587 MHz is presented here.  Resonators/filters of other frequencies such as 5.5 MHz, 7 MHz and 10.7 MHz may also be used.  Use of different frequency filters/resonators will involve corresponding variation in the value of inductor used in the tank circuit of oscillator connected at the collector of transistor T1.__ 

Powering a Fractional-N Voltage Controlled Oscillator (VCO) with Low Noise LDO Regulators for Reduced Phase Noise  -  The EVAL-ADF4350EB1Z board uses the standard ADF4350 programming software, contained on the CD that accompanies the evaluation board.  , Equipment Needed Windows® XP, Windows, Vista (32-bit) , or Windows 7 (32-bit) PC with USB Port, the ADF4350EB1Z, the ADF4350 programming software, 5.5 V power supply, and a spectrum analyzer such as a Rhode and Schwartz FSUP26.  __ Analog Devices from the Lab

PowerLabs Flyback Driver -  This is by far the best project for someone who is already familiar with High Voltage, but wants to take their experiments to the next level: it requires very little previous experience and skills with soldering and identifying components, and there are virtually no adjustments to be made.  The danger is minimal, as fly back transformers are intrinsically low power devices, not capable of outputting lethal currents (due to the hair-thin secondary windings) , and yet it will give a careless experimenter a nasty RF burn if he accidentally touches the HV wire (nothing beats learning from your mistakes).  if you have never experimented with HV before though, I recommend you start off with an electrostatic project.  This circuit is not a toy!  __ Designed by Sam Barros

Practice safe DC/DC converter -  07-Jul-00 Published in EDN (scroll to find this one.) Short-circuit protection is an obvious requirement for a power supply, especially when its load connects to a cable that’s subject to damage.   __ Designed by Eugene Kaplounovski, Nautilus International, Vancouver, Canada

Precharged Capacitor Ensures High-Side Start-U -  08/17/95 EDN Design Ideas:  when you use a high-voltage bridge driver, such as the iR2110 or the newer iR2155, a complete driver circuit can exhibit erratic behavior when you apply power if it is designed exactly right __ Circuit Design by Christophe Basso, European Synchrotron Radiation Facility, Grenoble, France

Precise Low Voltage Power Supply -  This power supply eliminate voltage loss on current meter.  Will be designed for measure on low voltage DC/DC converters (e.  g.  LED lamps powered from single NiCd/NiMH
cell).  __ 

Programmable source powers DC micromotors -  03/01/01 EDN Design Ideas:  A simple, economic, compact, and tricky way of using the LM723 as a programmable voltage source to drive dc micromotors which can set the output to a value of200 mV to 6V __ Circuit Design by V Dubey

Protection Feature Enhances Boost Converter -  10/27/94 EDN Design Ideas:  A boost-topology switching regulator is the simplest solution for converting a two to three-cell input to a 5V output.  Unfortunately, boost regulators have several inherent disadvantages, including a lack of short-circuit protection and shutdown capability.  in some battery-operated __ Circuit Design by Dimitry Goder, Linear Technology Corp, Milpitas, CA

Provide High-Side Current-Sensing for White-LED Drivers -  02/19/04  EDN Design Ideas:  White LEDs find wide use in backlighting color-LCD screens in most portable devices, such as cellular phones, PDAs, and MP3 players.  Multiple LEDs often connect in series to ensure that the same current flows through every LED.  To  __ Circuit Design by Dimitry Goder, Sipex Corp, San Jose, CA

Provide Leading-Edge Blanking -  05/29/03  EDN Design Ideas:  in isolated switch-mode power supplies using peak-current-mode control, generally the current-sense resistor senses the current on the primary side of the power converter.  Figure 1 shows a typical circuit, in which R2 is the curren __ Circuit Design by Michael O'Loughlin, Texas Instruments, Dallas, TX

Provide Universal AC-Input-Voltage Adapter -  08/25/11  EDN Design Ideas:  Use a TRIAC and optocoupler to automatically change between doubler and bridge configurations.  he input-rectifier stage of an offline power supply converts an ac-line voltage to a dc voltage, which powers a dc/dc converter.  if you configure the rectifier section as a full-wave bridge for a universal mains input of 92 to 276V rms and 47 to 63 Hz, you must design the dc/dc converter to operate over a wide range of input voltages.  This approach increases the cost of components and reduces the efficiency of the dc/dc converter.   __ Circuit Design by JB Castro-Miguens, Cesinel, Madrid, Spain, and C Castro-Miguens, University of Vigo, Vigo, Spain

Provides +5 Volt Gate Bias from  48 Volt Input -  App Note #1803__ Maxim Integrated

Provides 1.5v, 7a Bus Termination -  09/14/95  EDN Design Ideas:  Some of the newest high-performance processors require a 1.5V bus terminator that can source currents as high as 7A.  This terminator requires a very fast transient response, because the device must react to high peak-current changes that have extremely fa __ Circuit Design by Chester Simpson and Mineo Yamatake, National Semiconductor, Santa Clara, CA

Provides 5v Gate Bias from –48v -  09/19/02 EDN Design Ideas:  A small and simple circuit derives 5V from the -48V rail that telecomm applications typically use (Figure 1).  Useful for gate bias and other purposes, the 5V supply delivers as much as 5-mA output current.  A shunt reference __ Circuit Design by William Hadden

Pulsing Charge Pump Drives Capacitive Loads -  11/05/98 EDN Design Ideas:  (Several circuits here, scroll to find this one) The test circuit in Figure 1  efficiently drives various capacitive loads, such as memory cells and simple capacitors, so that you can observe their leakage effects.  Essentially, the circuit is a pulsed and variable current source acting as a charge pump.  A pulsed voltage source drives a one-shot oscillator __ Circuit Design by Paul J Rose, Mental Automation Inc, Bellevue, WA

Push-pull driver provides isolated 5V at 1A -  03-Mar-00 EDN Design Ideas:  The circuit in Figure 1 converts a regulated 5V input to an isolated 5V output with 1A current-output capability.  iC1, a pushpull transformer driver, powers a pair of cross-coupled power MOSFETs in a flipflop-like configuration.  NOTE  PDF contains several circuits, scroll to find this one.    __ Circuit Design by Ron Young, Maxim Integrated Products, Sunnyvale, CA

PV Inverter Design using Solar Explorer Kit (Rev. A) -  Photovoltaic (PV) installations tied to the grid are usually built with arrays of modules connected in series to string inverters.  An emerging system architecture to harvest more energy per module by supplementing the conventional string inverter uses dc-dc converters dedicated to individual modules.  These systems, known as microconverters or dc-dc power optimizers address partial shading and other aging issues by implementing maximum power point tracking (MPPT) at the individual module level so that underperforming modules do not constrain the entire string __ Designed by Texas Instruments App Notes, 23-Jul-13

PWM controller drives LEDs from high-voltage lines -  4-Mar-04 EDN Design Ideas:  Powering LEDs from a wide dc range—say, 30 to 380V—without wasting a lot of power in the regulating block, is a difficult task when the LED current needs to be constant.  Dedicated LED drivers are available, but they usually implement boost structures and are thus inadequate for high-voltage inputs __ Circuit Design by Christophe Basso, On Semiconductor, Toulouse, France

PWM IC makes synchronous gate driver -  02/02/99 EDN-Design ideas (contains several designs, scroll to find this one) A system with a µP, memory, and peripherals usually requires several power-supply voltages.  Designers typically use local switching regulators to produce the desired voltage rails.  One of the most common topologies, the synchronous buck regulator, converts a 5 or 12V bus to some other, lower voltage.   __ Circuit Design by Dimitry Goder, Switch Power Inc, Campbell, CA

Quad DC/DC Converter for Triple Output TFT Supply Plus LED Driver -  LT1942__ Linear Technology/Analog Devices

Quad Output Switching Converter Provides Power for Large TFT LCD Panels -  DN349 Design Notes__ Linear Technology/Analog Devices

Quasiresonant converter uses a Simple Circuit CMOS IC -  04/15/04  EDN Design Ideas:  Figure 1 shows a flyback power supply that has low noise and uses a simple CMOS 4093 IC for its control.  The electrical noise of a converter arises mainly when current switches on.  Diode recovery and charging parasitic capacitances __ Circuit Design by Francesc Casanellas, Aiguafreda, Spain

Quasiresonant Flyback Converter Easily Charges Energy-Storage Capacitors -  23-Jul-09 EDN Design Ideas:  increase energy transfer by using boundary-conduction mode __ Circuit Design by Todor Arsenov, Toronto, ON, Canada

Quickly discharge power-supply capacitors -  07/05/01  EDN Design Ideas:  A perennial challenge in power-supply design is the safe and speedy discharge, or "dump, " at turn-off of the large amount of energy stored in the post-rectification filter capacitors. This energy, CV2/2, can usually reach tens of jo __ Circuit Design by Stephen Woodward, University of North Carolina, Chapel Hill, NC

Recover the leakage energy of a flyback transformer -  04/18/13  EDN Design Ideas:  This design can recover the leakage energy of a flyback transformer and minimize over-voltage stress to the switching device.   __ Circuit Design by Todor Arsenov

Reduce EMI by sweeping a power supply's frequency -  27-May-04 EDN Design Ideas:  Switching power supplies can be notorious noise generators.  You should prevent this noise, which is conducted, radiated, or both, from returning to the input source, where it can potentially wreak havoc on other devices operating from the same input power.  The goal of an EMi (electromagnetic-interference] filter is to block this noise and provide a low-impedance path back to the noise source __ Circuit Design by John Betten, Texas Instruments, Dallas, TX

Reduce negative-voltage stresses on control IC -  04/18/02  EDN Design Ideas:  in a synchronous, buck switching power supply, the two FETS and the output inductor meet at the phase node (Figure 1).  The phase node often connects directly to the control iC.  The voltage on this node swings from the input voltage  __ Circuit Design by Michael Day, Texas Instruments Inc, Dallas, TX

Reducing ground bounce in DC/DC-converter applications -  07/06/06 EDN Design Ideas:  Electrical ground, which looks simple on a schematic, can become complex depending on how you lay out the pc board.  Unfortunately, ground-node analysis is difficult.  However, understanding the physics of ground noise helps to reduce the problem __ Circuit Design by Jeff Barrow, Analog Devices

Regulated Charge Pump Delivers 50ma -  App Note #35__ Maxim Integrated

Regulated Linear power supply with LM317-1.5, 3, 4.5, 5, 6 & 9 Volt -  Normally begin to learn about electronics power supply from the battery, for example, 9 volts, 1.5 volts, 6 volts etc.  But there are disadvantage that when using battery power is discharged.  I need to buy a new one.  Consume more.  We should the dc power supply have a choice of AC voltage.  Which it must […] __ Designed by Antonio Rodrigues

Regulated Step Up Converter Provides High Efficiency Without Inductors -  App Note #44__ Maxim Integrated

Regulator Generates as Many as Four Voltages -  08/03/95 EDN Design Ideas:  The inexpensive switching regulator in Fig 1 provide as as many as four voltages using a single quad comparator.  The circuit can implement two positive regulated supplies and two semiregulated negative supplies that use a charge-pump technique.  Fig 1's circuit, which costs $4.48 in moderate volumes, shows three of the four possible output voltages, ±9V and 150V.  You can add a 150V supply using the same charge-pump techniques as the 9V supply.  Output current of the +9V supply is nominally 10 mA.    __ Circuit Design by D Hayden, Hayden Electronics Design, San Diego, CA

Regulator has One Active Part -  03/16/95 EDN Design Ideas:  The regulator of unusual simplicity (ROUS) in Fig 1 derives a low-voltage, low-current output from rectified 115 to 270V ac.  Pass transistor Q1 is the regulator's only active component.    __ Circuit Design by Kennan C Herrick, ESI Electronics Corp San Francisco, CA

Regulator Makes Dual Tracking Reference -  11/07/96 EDN Design Ideas:  You can use the venerable 723 voltage regulator in new and unusual ways.  For example, you can modify its topology as in Figure 1 to yield a low-component-count, dual-polarity tracking voltage reference.  The 723, a long-time standard in power-supply design, is a flexible IC that includes a temperature-compensated voltage reference, an error amplifier,  __ Circuit Design by James Mears, National Semiconductor, Tacoma, WA

Regulator provides ±12V -  10/23/97 EDN Design Ideas:  Simple circuit can provide ±12V from a5V input using only one switching-regulator IC and a few off-the-shelf __ Circuit Design by Musiri Shrivathsan, National Semiconductor Corp, Santa Clara, CA

Relay: Transistor Boosted -  This relay driver boosts the input impedance with a regular 2N3904 transistor (or equivalent).  Very common driver.  it can drive a variety of relays, including a reed-relay, and is non-latching. 
Transistor Q1 is a simple common-emitter amplifier that increases the effective sensitivity of the 12 volt relay coil about a 100 times.   __ Designed by Tony van Roon  VA3AVR

Replaces & Improves On Power Modules At Less Than Half the Price -  DN347 Design Notes__ Linear Technology/Analog Devices

Restore DC to NRZ sigmals -  10/28/99  EDN Design Ideas:  For NRZ signals, ac amplification is preferable to dc amplification, because ac amplification is usually more economical and has greater immunity to drift.  However, ac processing has the disadvantage that ac coupling removes the dc reference level of the __ Circuit Design by Jay Kirschenbaum

RMS-To-DC Converter Is Accurate & Stable -  09/14/95 EDN Design Ideas:  Combining the well-known true rms-to-dc circuit with a simple S/H circuit eliminates offset errors, which increases accuracy and temperature stability.  The circuit in Fig 1 uses a low-cost analog multiplier, iC1; an integrator, iC3A, R5, and C1; and an analog inverter,  __ Circuit Design by Sergey Velichko, SCP, Boise, ID

Royer Flyback driver -  This circuit is an auto-oscillating, resonant, current fed High voltage DC-DC converter.  The output voltage is calculated as follows Vout = Vin * pi * Nsecondary / Nprimary.  The primary peak voltage is Vin * pi , and the rms voltage is Vin*pi*0.7 __ 

RS-232 Serial Interface Status Indicator Circuit -  i designed this circuit many years ago and have used it several times since.  it uses a single logic IC to indicate the TXD and RXD line activity of a typical RS-232 serial data communications link.  The thresholds are set at plus 3 volts and minus 3 volts.  Two dual color LEDs are used as indicator lights . . . Hobby Circuit designed by Dave Johnson P.E.-December, 2007

RX 5.0 VDC to 3.0 VDC CONVERSION -  Schematic only, there is no circuit description __ Designed by Lee A. Mrha

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