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Voltage Regulator Circuits

Voltage Regulators:  #'s - A       B - D       E - K       L - Q       P - S      
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Last Updated: 11/30/2017 07:17 AM

Circuits Designed by Dave Johnson, P.E. :

Capaciatance-Based Touch Switch -  This is another capacitance based touch on/touch off switch, which can control power to a 200 watt 240vac load . . . Hobby Circuit designed by David Johnson P.E.-July, 2006

Caps Provide Voltage Boost to Series Regulator -  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. . . Circuit by David Johnson P.E.-January, 1998

Circuit Eliminates 9v Battery -  if you use 9v battery powered devices for long periods of time, you may get tired of constantly changing batteries.  The circuit below can be wired into any 9v battery powered device, drawing power from an external AC to DC power adapter.  I designed the c . . . Hobby Circuit designed by David A. Johnson P.E.-December, 2009

Classic Linear 5v Supply using 6.3vAC Transformer -  A classic method for producing a regulated +5v DC supply is shown below.  This circuit consists of an iron core transformer, a bridge rectifier, a filter capacitor and a voltage regulator.  Many people are tempted to use a very popular 6.3v transformer. . . Circuit by David Johnson P.E.-February, 2009

Capacitance Proximity Switch
Draws very low power - Ideal for battery-powered applications
6 Models Available - Call 806-368-7747

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

Circuitry for Signal Conditioning & Power Conversion -  AN75 Linear Technology This publication includes designs for data converters and signal conditioners, transducer circuits, crystal oscillators and power converters.  Wideband micropower circuitry receive special attention.  Tutorials on micropower design techniques and parasitic effects of test equipment are included.  __ Linear Technology/Analog Devices

Circuitry for Single Cell Operation -  AN15 1.5V powered circuits for complex linear functions are detailed.  Designs include a V/F converter, a 10-bit A/D, sample-hold amplifiers, a switching regulator and other circuits.  Also included is a section of component considerations for 1.5V powered linear circuits.  __ Linear Technology/Analog Devices

Circuits Sort Out the Highest Voltage -  11/09/06  EDN Design Ideas:  Greatest-of-three voltage detector drives indicators and external display __ Circuit Design by Ezio Rizzo, Nova SNC, Genoa, Italy, and Vincenzo Pronzato, Felmi SRL, Genoa, Italy

Clairvoyance Marries Remote Sensing -  Linear Technology AN126 __ Designed by Jim Williams - Oct 1st, 2010

Classic Linear 5v Supply using 6.3vAC Transformer -  A classic method for producing a regulated +5v DC supply is shown below.  This circuit consists of an iron core transformer, a bridge rectifier, a filter capacitor and a voltage regulator.  Many people are tempted to use a very popular 6.3v transformer. . . Circuit by David Johnson P.E.-February, 2009

Cockcroft Walton Diode Voltage Multipliers -  These circuits generate high voltages and can cause dangerous shocks!  Do not build these devices unless you are experienced and qualified to work on high voltage devices. __  Contact:  Charles Wenzel of Wenzel Associates, Inc.

Collection of Battery Chargers -  Collection of battery charger circuits __  Contact:  Charles Wenzel of Wenzel Associates, Inc.

Collection of High Voltage Circuits -  Collection of Power Supplies /Regulators __  Contact:  Charles Wenzel of Wenzel Associates, Inc.

Compact Inductorless Boost Regulates White LED Bias Current -  App Note #1116__ Maxim Integrated

Compact Step-Up Converter Conserves Battery Power -  DN358 Design Notes __ Linear Technology/Analog Devices

Compact μTCA 12V & 3.3V Hot Swap Solution for Advanced Mezzanine Cards -  The LTC4223 positive voltage Hot Swap controller allows a board to be safely inserted and removed from a live AMC or MicroTCA backplane.  it controls the main 12V supply with an external N-channel MOSFET and the 3.3 V auxiliary supply with an integrated switch.  The 12V output ramp rate is adjustable and includes inrush current __ Linear Technology/Analog Devices App Note, Mar 26th 2010

Constant Current Battery Charger -  A simple method of charging a battery from a higher voltage battery is shown in the circuit below to the left.  Only one resistor is needed to set the desired charging current and is calculated by dividing the difference in battery voltages by the charge current.  So, for example if 4 high capacity (4000 mA hour) ni-cads are to be charged at 300 mA from a 12 volt battery, the resistor need,  __ Designed by Bill Bowden

Constant Voltage-Constant Current Regulator -  With switching frequency as high as 500kHz, The LT®1510 current mode PWM battery charger is the smallest, simplest, most efficient solution to fast-charge modern re-
chargeable batteries including lithium-ion (Li-ion) , nickel-metal-hydride (NiMH
) * and nickel-cadmium (NIC d) * that require constant-current and/or constant-voltage charging.  The internal switch is capable of delivering 1.5A DC current (2A peak current)  __ Designed by LT1510/LT1510-5 Application Note

Constructing the +12 Volt Supply  -  While power supply requirements for digital circuits are rather simple and direct, a power supply for analog circuits is less specific, and therefore harder to precisely define.  instead of a simple, "All circuits require a 5 volt power source, " we can have a wide range of power supply requirements.  A common power requirement for portable low-power equipment such as a basic transistor radio is 9 volts, so it can be powered from a compact 9-volt battery.  Equipment designed for use in cars typically operates on 12 volts.  Others require 3 volts, or 6 volts, or 15 volts.  Or something else.  Many circuits require both positive and negative power supplies.  There is no end to the variations.   __ Designed by Ken Bigelow

Constructing the +5 Volt Supply  -  The +5 volt supply is useful for both analog and digital circuits.  DTL, TTL, and CMOS ICs  will all operate nicely from a +5 volt supply.  in addition, the +5 volt supply is useful for circuits that use both analog and digital signals in various ways.  More importantly for our purposes, the +5 volt supply will be used as the primary reference for regulating all of the other power supplies the we will build.  We can do this very easily if we use operational amplifiers as the controlling elements in the power supply circuits.  We'll see how this works after completing the basic +5 volt supply __ Designed by Ken Bigelow

Constructing the-12 Volt Supply  -  The -12 volt power supply is not required for all possible analog circuits; many require only the +12 volt supply you have already built and tested.  However, a number of analog circuits do require power supplies of both polarities so that their inputs and outputs can handle and deal with both positive and negative voltages.  The most generally familiar device that requires dual power supplies is the Operational Amplifier __ Designed by Ken Bigelow

Control an LM317T with a PWM signal -  02/03/11  EDN Design Ideas:  Set a regulator's output voltage under microprocessor control.  The LM317T from National Semiconductor is a popular adjustable-voltage regulator that provide as output voltages of 1.25 to 37V with maximum 1.5A current.  You can adjust the output voltage with a potentiometer.  The circuit in Figure 1 replaces the potentiometer with an analog voltage that you can control from a PWM (pulse-width-modulation) signal.  You control this signal with a microcontroller or any other digital circuit.  You can use the same microcontroller to dynamically monitor the output and adjust the LM317T.   __ Circuit Design by Aruna Rubasinghe

Convert voltage to potentiometer-wiper setting -  09/05/02 EDN Design Ideas:  The circuit in Figure 1converts an analog input voltage, ViN, to a proportional wiper setting of a DPP (digitally programmable potentiometer].  The potentiometer's wiper setting, which varies from position 0 through 31, corresponds to the input voltage, which varies from 0 to 1V dc.  The CAT5114, IC 5, is a 32-tap potentiometer with an increment/decrement interface __ Circuit Design by Chuck Wojslaw, Catalyst Semiconductor, Sunnyvale, CA, and Chris Wojslaw, Conexant Systems, Newport Beach, CA

Create a Virtual Ground with the LT1118-2.5 Sink/Source Voltage Regulator -  DN115 Design Notes __ Linear Technology/Analog Devices

Critical-mode control stabilizes switch-mode power supplies -  04/23/98 EDN Design Ideas:  Discontinuous-conduction-mode operation eases switch-mode power-supply design and allows for better response to step-load changes.  Operating at the critical-conduction point--beginning a new cycle at the exact point the inductor current falls to zero--ensures that the converter stays in discontinuous-conduction mode. __ Circuit Design by Christophe Basso, Motorola Semiconductors

Cúk converter yields 90% efficiency -  EDN-Design ideas-- 09/01/94    The simple DC/DC converter in Fig 1 has an efficiency of 90% min and output ripple measured at 10 mV p-p.  This circuit employs an inexpensive 78L15 regulator in an unusual manner.  The regulator, IC 2, operates as a voltage-level shifter.  Because the regulator's normal output is tied to ground, the regulator tries to maintain its input at its characteristic 15V above its voltage-reference (VR) pin's level by drawing the appropriate current through biasing resistor R1.   __ Circuit Design by Peter Demchenko, VN, Vilnius, Lithuania

Current booster for 78nn series voltage regulators -  Volt regulators such as the LM708, and LM317 series (and others) sometimes need to provide a little bit more current then they actually can handle.  if that is the case, this little circuit can help out.  A power transistor such as the 2N3772 or similar can be used (See the project on the 3-part variable power supply)  __ Designed by Tony van Roon  VA3AVR

Current-sensing scheme improves PFC on/off sequences -  06/27/02 EDN Design Ideas:  PFC (power-factor-correction] preconverters typically use the step-up, or boost, configuration, because this type of converter is relatively easy to implement (Figure 1).  However, this topology requires the output voltage to be higher than the input voltage.  When this condition is not the case—for example, with on/off sequences or under load conditions—some inrush current flows thro __ Circuit Design by Joël Turchi, On Semiconductor, Toulouse, France

DAC & Op Amp provide variable-control voltage -  12/06/01 EDN Design Ideas:  Early DACs contained standard R-2R ladder networks, and produced a negative output voltage.  These early DACs, such as the MAX7837/7847 and the MAX523, require both positive and negative supply rails to accommodate their negative output.  With the transition to single-supply IC s, however, many modern DACs operate with a single supply rail and an inverted R-2R ladder network __ Circuit Design by Chad Olson, Maxim Integrated Products, Sunnyvale, CA

DAC Fine-Tunes Reference Output -  08/25/11  EDN Design Ideas:  Adding a DAC and op amp makes a precision adjustable reference.  Data converters must have a stable reference voltage to accurately measure or generate analog signals.  Such references offer many guaranteed levels of precision and stability.  Their variety of output-voltage levels is much smaller, which manufacturers specify as standard values, such as 2.048, 2.500, or 4.096V.  You sometimes need to dynamically calibrate the reference, fine-tune its output value, or generate a slightly different value.  For instance, when you measure a voltage with a resistive divider, you could adjust the reference voltage to compensate for an error in the divider __ Circuit Design by Fons Janssen, Maxim Integrated Products, Bilthoven, Netherlands

DC Adapter Power Supply -  DC voltage "virtual earth" circuits __ Designed by Rod Elliott  ESP

DC switching regulator (Mk I) -  This is an experimental circuit which rapidly "chops" a steady DC input voltage to produce a lower output voltage. Regulation is a function of the chopping - it is caused by the output transistor switching on and off around the target voltage, which when smoothed provides a constant DC output. __ Designed by Rowan from Melbourne, Australia

DC switching regulator (Mk II) -  A simpler and more efficient version of the above.  Uses a 78Lxx device as a voltage reference and a comparator.   __ Designed by Rowan from Melbourne, Australia

DC Voltage & Current Source -  A reference voltage and current source for testing data converter and analog amplifier.  A simple circuit built with TI LinCMOS OpAmp, TLC254C provides multiple outputs: +2.5V, 0 to +2.5V and 0 to 250uA.  The circuit is operated with 9V battery. __ Designed by Wichit Sirichote

DC Voltage Multiplier Plans -  Build a circuit to boost the voltage of a DC power source using a MAX756 IC Chip.   __ Designed by REUK-Renewable Energy UK website

DC/DC Converter Increases Available Power in Dual Voltage System -  01/08/04 EDN Design Ideas:  The schematic in Figure 1 shows a way to increase the power available from a current-limited 5V supply by adding power from a -5V supply.  The DC/DC converter generates a single 12V, 150-mA (1.8W]output from two regulated and current __ Circuit Design by David Kim, Linear Technology App Note, Milpitas, CA

DC/DC converter operates from phone line -  01/15/98 EDN-Design ideas DC/DC converters for use inside the telephone handset require operation from the high-source-impedance phone line.  Additionally, the CCiTT specifications call for maximum on-hook power consumption of 25 mA.  The DC/DC converter in Figure 1 is 70%-efficient at an input power of 25 mA, providing 5V at 3.4 mA.  Controlled, low-peak switch __ Circuit Design by Gary Shockey, Linear Technology Corp, Milpitas, CA

DC-DC converter starts up & operates from a single photocell -  03/20/13  EDN Design Ideas:  Reduce the parts count from the suggested data sheet circuit of this energy harvester.   __ Circuit Design by Larry Suppan

DC-DC converters -  Two converters are shown here.  One powers a VCR or similar device from a car battery, while the other powers a model airplane glow plug from 12V. __ Designed by Manfred Mornhinweg

DC-Voltage Doubler Reaches 96% Power Efficiency -  07/15/10 EDN Design Ideas:  Analog switches let you charge a capacitor from two directions __ Circuit Design by Marián Štofka, Slovak University of Technology, Bratislava, Slovakia

Design a Simple, Efficient & Reliable Forward Converter -  Due to the high cost and inflexibility of isolated DC/DC converter modules, many designers are choosing to implement a discrete design that is better matched to their application.  in particular, the forward converter with active clamp reset has been widely used in custom supplies because of its excellent efficiency and reduced__ Linear Technology/Analog Devices App Note, Kurk Mathews Senior Applications Engineer-Power Products Jun 14th 2012

Design Notes 503: Dual DC/DC Controller for DDR Power with Differential VDDQ Sensing & ±50mA VTT Reference -  11/01/13  EDN-Design Notes   Solid-state circuit breaker for microcontrollers.  The LTC3876 is a complete DDR power solution, compatible with DDR1, DDR2, DDR3, and DDR4 lower voltage standards.  The IC includes VDDQ and VTT DC/ DC controllers and a precision linear VTT reference.  A differential output sense amplifier and precision internal reference combine to offer an accurate VDDQ supply.  The VTT controller tracks the precision VTTR linear reference with less than 20mV total error.  The precision VTTR reference maintains 1.2% regulation accuracy, tracking one-half VDDQ over temperature for a ±50mA reference load.   __ Circuit Design by Ding Li

Design Notes 504: 42V 2.5A Synchronous Step-Down Regulator with 2.5μA Quiescent Current -  11/26/13  EDN-Design Notes   Measure inductance & capacitance over a wide range.  The LT8610 and LT8611 are 42V, 2.5A synchronous step-down regulators that meet the stringent high input voltage and low output voltage requirements of automotive, industrial, and communications applications.  To minimize external components and solution size, the top and bottom power switches are integrated in a synchronous regulator topology, including internal compensation.  The regulator consumes only 2.5μA quiescent current from the input source even while regulating the output.   __ Circuit Design by Hua  Walker Bai

Desktop Power Supply -  Useful for electronics hobbyists, this linear workbench power supply converts a high input voltage (12V) from the SMPS of a PC into low output voltage (1.25 to 9 volts).  An adjustable...__ Electronics Projects for You

Desktop Power Supply from a PC -  This ATX PS board has leads for +5 (RED) , -5 (WHiTE) , +12 (YELLOW) , -12 (BLUE) volts, Ground (BLACK) and switch (GREEN).  Dell power supplies manufactured between 1996 and 2000 do not follow the industry standard pinout and color codes.  The fan has also been unplugged for better viewing.  Since this PS was converted for use in the logic and robotics labs, the selected voltages  __ Designed by Andy Batts   

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

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