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Voltage Regulator Circuits

Voltage Regulators:  #'s - A       B - D       E - K       L - Q       P - S      
T - Z


Last Updated: 09/06/2020 02:31 PM

Circuits Designed by Dave Johnson, P.E. :

Touch Switch 240VAC -  This is another capacitance based touch on/touch off switch, which can control power to a 200 watt 240vac load . . . Hobby Circuit designed by Dave Johnson P.E.-February, 2002

Ultra Low Power Human Finger Detector -  The circuit below seems to work well and averages a current drain of only 10 microamps from a lithium cell.  it uses a single CA4013 dual D flip/flop.  One section is wired as a pulse generator.  it applies 10us 10ma pulses to a LED inside a slotted optical sensor at a rate of about 50Hz.  The phototransistor in the second half of the sensor detects the pulses and sends a pulse to the data input of the second flip/flop in the 4013 package.  if there is nothing between the LED and the phototransistor, the inverting output of the 4013 remains low.Circuit Solution by David A. Johnson P.E.-May, 2006

Variable Isolated AC Voltage Spans 0VAC to 280Vac -  I designed and built this circuit about 25 years ago.  it came in handy for many projects that were powered from 120 VAC, 240 VAC and 277 VAC.  it provides complete isolation from the power line.  it uses two 1:1 isolation transformers that are wired in parallel. . . Circuit by David A. Johnson P.E.-July, 2000

Voltage Boost -  in this design a marginal AC to DC linear power supply provides a voltage boost, so it can maintain regulation at low line voltages.  The added components are wired at the AC input and the + DC output of an existing bridge rectifier circuit.  The components act as a full wave “charge pump” which will boost the DC output voltage across the main filter capacitor C3.  Without the boost circuit, when the AC line voltage drops to 105vac, the DC output voltage only reaches 11.5 volts, too low for a 12v voltage regulator. . . . Hobby Circuit designed by Dave Johnson P.E.-July, 2006

Voltage Boost to Series Regulator provided by Capacitor -  This circuit adds some capacitors and diodes to a traditional transformer type series regulator circuit to extend the normal operating range.  it can insure regulation during low line voltage conditions or it can squeeze a few more watts out of a plug-in-the-wall power adapter power supply . . . Hobby Circuit designed by David Johnson P.E.-January, 1998

Voltage Converters-0.5 to 6 Volts -  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. . . Circuit by Dave Johnson P.E.-May, 2007 


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

Technique Improves Transient Dynamics -  06/24/99 EDN Design Ideas:  Designing low-voltage, high-current converters with fast dynamic performance places stringent demands on a system designer.  However, a simple technique reduces the peak voltage deviation and decreases the response time for a tran Design by Robert Sheehan, Linear Technology Corp, Milpitas, CA

The architecture of a low-noise, Low-dropout regulator -  05/11/00  EDN Design Ideas:  Figure A shows a design scheme for a low-noise, low-dropout regulator that the LT176X through LT196X family of regulators uses.  This scheme minimizes noise transmission within the loop and minimizes noise from an unregulated input.  The bypass capacitor, C Design by EDN Staff

ThinSOT Micropower Buck Regulator has Low Output Ripple -  DN373 Design Notes__ Linear Technology/Analog Devices

ThinSOT Switching Regulator Controls Inrush Current -  DN365 Design Notes__ Linear Technology/Analog Devices

Three Phase Voltage Multiplier -  The Cockcroft-Walton turbine voltage multiplier.   __ Designed by REUK-Renewable Energy UK website

Three-Terminal Adjustable Regulators -    NOTE: Scroll down - The unregulated DC supply is a very common type and the simple regulator shown in fig.1 may be added for projects that require a stable voltage. __  Contact:  Charles Wenzel of Wenzel Associates, Inc.

Three-V supply Delivers 12V p-p to piezo speaker -  10/16/03  EDN Design Ideas:  Low-profile piezoelectric speakers can provide quality sound for portable electronic devices, but they require voltage swings greater than 8V p-p across the speaker element.  Yet, most portable devices include only a low-voltage pow Design by Royce Higashi and Tony Doy, Maxim Integrated Products, Sunnyvale, CA

Tiny & Efficient Boost Converter Generates 5V at 3A from 3.3V Bus -  DN280 Design Notes__ Linear Technology/Analog Devices

Tiny Buck Regulator Accepts Inputs from 3.6V to 25V & Eliminates Heat Sink -  DN268 Design Notes__ Linear Technology/Analog Devices

Tiny Highly Flexible Dual Boost/Inverter Tracks Supplies -  DN357 Design Notes__ Linear Technology/Analog Devices

Tiny Regulators Drive White LED Backlights -  Design Notes 231__ Linear Technology/Analog Devices

Tiny Versatile Buck Regulators Operate from 3.6V to 36V Input -  DN367 Design Notes__ Linear Technology/Analog Devices

TL431 shunt regulator limits high AC input voltage -  10/25/07  EDN Design Ideas:  This circuit clamps input-ac voltages to levels safe for the operation of the power MOSFET in an SMPS Design by Todor Arsenov, STMicroelectronics, Prague, Czech Republic

Touch Switch 240VAC -  This is another capacitance based touch on/touch off switch, which can control power to a 200 watt 240vac load . . . Hobby Circuit designed by Dave Johnson P.E.-February, 2002

Transformerless Power Supply -  I have received a few emails asking for a transformerless power supply.  Here is such a supply.  This supply uses no heavy step down transformer and has an extremely low parts count.  The circuit can be built very small and can supply small currents for small projects.  The major downfall of this supply is that it is not isolated from the AC line and can only supply small currents __ Designed by Aaron Cake

Transformerless Power Supply (jose pino) -  Simple, low cost and easy to build power supply.  ideal for applications that doesn't require too much power. (5/28/2006)  __ Designed by Jose Pino

Transistor quickly wakes sleeping LDO -  09/01/98 EDN Design Ideas:  NOTE:     FILE
has many circuits, scroll down.  Portable systems, such as telephone handsets, make extensive use of low-dropout (LDO) regulators.  These components provide noise-sensitive parts with a stable power-supply line.  When a telephone enters standby mode, most of the circuits go to sleep by disabling the LDO's outputs.  Operating current thus drops to a minimal level.  When a user starts to dial a number, the LDO receives an enable signal and immediately delivers the nominal operating voltage.  Unfortunately, most low-noise LDOs use a bypass capacitor that briefly loads the internal reference voltage upon wake-up. Design by Christophe Basso, Motorola Semiconductor, Toulouse, France

Triggered spark gap -  This is purely a construction article.  __ 

Twin T power oscillators work as DC-biased AC sources -  9-Apr-09 EDN Design Ideas:  Using a frequency-selective twin-T network and the LT3080 linear regulator, you can achieve a low-distortion twin-T oscillator with power-driving capability Design by Tiger Zhou and Robert Dobkin, Linear Technology, Milpitas, CA

Two AA cells power step-down regulator -  01/07/99 EDN Design Ideas:  (Scroll to find this one) DC/DC conversion is particularly challenging when both the input and output voltages are low.  Step-up ICs  that operate with inputs lower than 1V are available, but step-down ICs  that accept input voltages   Page includes several designs.   Design by Len Sherman, Maxim Integrated Products, Sunnyvale, CA

Two Channel Gate Driver for Large IGBT Modules -  The BG2A is a fully isolated two channel gate drive Circuit designed for use with dual iGBT modules.  The BG2A utilizes Powerex VLA500-01 or VLA502-01 hybrid gate drivers to provide efficient switching of modules rated up to 1400A.  The hybrid gate driver features a built-in high speed opto-coupler, short circuit protection and an isolated DC to DC converter with 2500VRMS isolation.

Two Phases to Cut Current & Improve EMI -  11/12/09 EDN Design Ideas:  in DC/DC-converter applications in which the input voltage may be lower or higher than the output voltage, you can use either a flyback converter or a SEPIC  (single-ended-primary-inductor converter).  SEPIC offer lower input-curre Design by Goran Perica, Linear Technology App Note, Milpitas, CA

Two Terminal Current Regulator (LT1635) -  The LT1635 combines an op amp with a 200mV reference.  Scaling this reference voltage to a potential across resistor R3 forces a controlled amount of current to flow from the +terminal to the –terminal.  Power is taken from the loop.  __ Linear Technology/Analog Devices App Note, Mar 31, 2010

Two Terminal Current Source -  The OpAmp buffers the upper potential of a shunt regulator to set a voltage drop on R1 equal to the reference.  The net current to RL is the programmed R1 current plus the quiescent supply current of the OpAmp passing through the reference.  __ Linear Technology/Analog Devices App Note, Jun 21st 2011

Two transistor regulators -  a theoretical discussion __ Designed by Richard Torrens

Two watt switching power supply -  in this small switching power supply, a Schmitt trigger oscillator is used to drive a switching transistor that supplies current to a small inductor.  Energy is stored in the inductor while the transistor is on, and released into the load circuit when the transistor switches off.  The output voltage is dependent on the load resistance and is limited by a zener diode that stops the oscillator when the voltage reaches about 14 volts.  Higher or lower voltages can be obtained by adjusting the voltage divider that feeds the zener diode.  The efficiency is about 80% using a high Q inductor.   __ Designed by Bill Bowden


Voltage Regulators:  #'s - A       B - D       E - K       L - Q       P - S       T - Z

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