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Power Supplies:  DC to DC / Switch Mode and DC to DC Converters
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Last Updated: June 02, 2021 01:44 PM

Circuits Designed by Dave Johnson, P.E. :

+5v Powered Charge Pump Battery Charger - The circuit below will trickle charge a four cell pack of AA or AAA NiMH batteries.  The circuit draws current from the +5v available a USB connection and pumps about 70ma of current into the battery.  This should be enough current to fully charge a pack of. . . Circuit by David Johnson P.E.-February, 2010

 0.5v Negative Supply - Although not very efficient, this simple circuit, consisting of two LEDs and a photo diode, 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,. . . Circuit by David A. Johnson P.E.-July, 2006

 0.5v to 6v Voltage Converter - Conventional silicon transistors just can't operate at voltages less than about 0.7v.  Old germanium transistors could be used, but those are hard to find these days and most are rather large in size.  Some new n-channel MOSFET devices with very . . . Hobby Circuit designed by David Johnson P.E.-May, 2007

 1 Watt Fluorescent Lamp Night Light - If you are tired of replacing small night light lamps, try this circuit.  The line powered circuit uses a long life cold cathode fluorescent lamp.  A simple charge pump technique runs the lamp without any transformer. . . Circuit by David A. Johnson P.E.-March, 1999

 125Khz LC Oscillator - This circuit adds more invertors in parallel to deliver more power.  It is similar to CMOS INVERTERS FORM 125KHZ OSCILLATOR.  Please note that the values shown are for 125KHz.. . . Circuit by Dave Johnson P.E.-March, 2002

 125KHZ Medium Power Ocsillator - 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 . . . Hobby Circuit designed by David Johnson P.E.-March, 2002

 125Khz Oscillator from CMOS Inverters - This circuit inverts the LC components so the inductor is grounded.  Two inverters are needed to produce the needed oscillation.  Again, the values shown set the frequency at 125KHz but can be changed to produce other frequencies. . . Circuit by David Johnson P.E.-March, 2002

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

 125Khz Ultra Pure Sine Wave Signal Source - For some RFID systems operating at 125KHz, a very low distortion signal source reference is needed.  The circuit shown on this page produces a 10-volt peak-to-peak signal into a 50-ohm load, with a distortion of only 0.01% . . . Hobby Circuit designed by Dave Johnson P.E.-February, 2002

 12v to 19v Laptop Power Supply (Concept) - Concept Only.  I have a big screen HP laptop computer.  The large brick size AC to DC power supply is rated at 19.2v and 9.5 amps, which is about 180 watts.  I’d like to be able to use the thing in my car.  I looked into a 12v car adapter for it but never really found one that I liked.  Most were underpowered.  The other option was to use the existing AC to DC adapter and run it off power from a 12v to 120vac inverter. . . Circuit by David Johnson P.E.-July, 2009

 12v Touch Switch Exciter Circuit - This circuit is designed to generate a 20KHz pseudo sine wave signal that can power about 50 remote touch activated switch circuits.    It can support a cable length of about 2500 feet.    A typical remote switch circuit is also shown as well as a receiver circuit for those switches.. . . Circuit by Dave Johnson P.E.-February, 2002


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

.4 watt 100% Radio Shack DC-DC Converter -  This DC-DC converter ("inverter") needs nothing but unmodified Radio Shack parts.  You don't need to build or wind any coils or transformers __ Designed by Don Klipstein

+30V power supply with +5V -  i made power supply which makes about +30V with +5V power supply.  Direct current is changed into alternating current by oscillator which used schmitt trigger inverter which has hysteresis characteristic and resonance circuit.  high DC voltage (+50V) is made with alternating voltage using voltage amplification rectification circuit __ Designed by Seiichi Inoue

+5V Power Supply -  This circuit is a small +5V power supply, which is useful when experimenting with digital electronics.  Small inexpensive wall tranformers with variable output voltage are available from any electronics shop and supermarket.  Those transformers are easily available, but __ Designed by Tomi Engdahl

+5v Powered Charge Pump Battery Charger -  The circuit below will trickle charge a four cell pack of AA or AAA NiMH batteries.  The circuit draws current from the +5v available a USB connection and pumps about 70ma of current into the battery.  This should be enough current to fully charge a pack of. . . Circuit by David Johnson P.E.-February, 2010

+9 Volt*and*  9 Volt from One Battery! -  MAX1044 is a charge pump converter it uses a capacitor as a "bucket" to pump charge from one place to anor.  it can be used to generate negative voltage easily __ Designed by R.G. Keen

±12V supply accepts 9 to 30V inputs -  12/04/97 EDN Design Ideas:  For applications that require symmetric supply voltages from a wide input range, the switch-mode supply in Figure 1 delivers more than 3.6W at �12V and operates from inputs of 9 to 30V.  Over this input range, efficiency varies from 74 to 80%.  The step-down switching regulator, iC1, includes an internal switching transistor that drives the primary side of the flyback transformer.  Matched output windings produce the ±12V outputs.    Design by Ron Young, Maxim Integrated Products, Sunnyvale, CA

±4 to ±18 Volt, 500 Milliampere D.C. Power Supply -  This is a simple, general-purpose power supply intended for laboratory applications that require both a positive and negative current.  The circuit uses commonly-available integrated circuit regulators that provide integral thermal overload protection as well as safe-area limiting.  These devices also provide regulation characteristics which are better than standard, fixed-voltage, three terminal regulators such as types 7812 and 7912 __ Designed by Arthur Harrison

µC controls charge pump as background task -  08/01/97 EDN Design Ideas:  Because of power consumption and cost, designers of battery-powered devices mainly choose components that run at 3V or lower.  Unfortunately, many devices operate only at 5V, including LCDs with built-in drivers, programming lines of many EEPROMs and flash chips, and CMOS ADCs Design by Carlos Cossio, Santander, Spain

How to Build a Versatile 0 to 12 Volt Adjustable DC Power Supply Unit -  Building the proposed circuit of 0 to 12 volt adjustable DC power supply is so simple that it may be even assembled even by a any electronic noob within half an hour.  Moreover, the maximum output voltage may not be restricted to just 12 volts, rather can be extended up to 32 volts (continuously variable) by just modifying the transformer ratings appropriately.  The whole operation becomes amazingly simple just due to the presence of this outstanding IC - LM 338. __ Bright Hub Engineering

0.2V Supply Voltage Nanopower Inverter -  Circuit ideas for Designers App Note__ Advanced Linear Devices, Inc

0.2V Supply Voltage Nanopower Two-Inputs NOR & NAND gates -  Circuit ideas for Designers App Note__ Advanced Linear Devices, Inc

0.2V Supply Voltage N-Channel Transmission Gate -  Circuit ideas for Designers App Note__ Advanced Linear Devices, Inc

0.5v Negative Supply -  Although not very efficient, this simple circuit, consisting of two LEDs and a photo diode, 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,. . . Circuit by David A. Johnson P.E.-July, 2006

0.5v to 6v Voltage Converter -  Conventional silicon transistors just can't operate at voltages less than about 0.7v.  Old germanium transistors could be used, but those are hard to find these days and most are rather large in size.  Some new n-channel MOSFET devices with very . . . Hobby Circuit designed by David Johnson P.E.-May, 2007

0-50V 2A Bench Power Supply -  i use the lm10 IC because it has a reference voltage and that's useful for dc power supply.  With two ICs can take different output voltage and amperage.  This circuit is protected from short circuit.  P2 is for controlling the current at the range of 0-2A.  Stabilize the output voltage with R4 on negative pin on op-amp and with R2 & P1 on positive pin __ Contact hamed_iranmehr @ yahoo.com

1 Cell Flashes White LED -  12/11/03 EDN Design Ideas:  Many portable appliances and other products that must operate from a single cell are restricted to working at very low voltages.  it is thus difficult to drive white LEDs that typically have a forward voltage of 3 to 5V.  The ability Design by Anthony Smith, Scitech, Biddenham, Bedfordshire, UK

1 cell lights any LED -  07/05/01  EDN Design Ideas:  The circuit in Figure 1 allows you to light any type of LED from a single cell whose voltage ranges from 1 to 1.5V.  This range accommodates alkaline, carbon-zinc, NiCd, or NiMH single cells.  The circuit's principal application is i Design by Al Dutcher, Al Labs, West Deptford, NJ

1 IC Biases LCD & GaAsFET Amplifier -  04/09/98 EDN Design Ideas:  (File , contains several circuits, scroll to this one) Operating from a lithium-ion cell or a four-cell NiCd battery, the circuit in Figure 1provide as 6V bias for LCDs and a separate, quiet negative bias for a GaAsFET power ampli Design by John Wettroth, Maxim Integrated Products, Apex, NC

1 Watt Fluorescent Lamp Night Light -  if you are tired of replacing small night light lamps, try this circuit.  The line powered circuit uses a long life cold cathode fluorescent lamp.  A simple charge pump technique runs the lamp without any transformer. . . Circuit by David A. Johnson P.E.-March, 1999

1.3V Power Supply -  This is a replacement power source for 1.3V mercury cells or other small batteries.  it has many uses and I use this circuit in my computer to power a front panel multi adapter which has a digital thermometer __ Designed by Andy Collinson

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 Design by Chester Simpson and Mineo Yamatake, National Semiconductor, Santa Clara, CA

10 Khz VFC uses Charge Pump Variation -  04/09/98 EDN Design Ideas:  (Several circuits included, scroll to find this one) A diode-capacitor charge pump is the starting point for many voltage-to-frequency-converter (VFC] designs.  The circuit in Figure 1 uses a variation on that classic theme to achieve linearity less than 0.05%, micropower operation of approximately 10-�A total draw from a 5 to 36V rail, and bipolar-input capability Design by Stephen Woodward, University of North Carolina, Chapel Hill, NC

10µA Quiescent Current Step-Down Regulators Extend Standby Time in Handheld Products -  DN235 Design Notes__ Linear Technology/Analog Devices

100ma UltraLow Noise Charge Pump LED Supply with Output Current Adjust -  LTC3201__ Linear Technology/Analog Devices

10-15W watt 100% Radio Shack DC-DC Converter -  This DC-DC converter ("inverter") needs nothing but unmodified Radio Shack parts.  You don't need to build or wind any coils or transformers.  This is a cheap-and-dirty experimenter's circuit.  I tested this and it worked for me, but I disclaim all warranties!  __ Designed by Don Klipstein

10A High Performance Point-of-Load DC/DC µModule -  DN385 Design Notes__ Linear Technology/Analog Devices

10A μModule step-down regulator with advanced input & load protection -  EDN Design Ideas:  07/01/2015    This switcher design has comprehensive electrical and thermal protection, and high efficiency over wide input-output ranges Design by LTC Design Note

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