Electronic Circuits and Tutorials
Electronics Schematics - V

Voltage Regulator Circuits

+5 Volt Power Supply Circuit

0 to 24 Volt 4Adjustable Power Supply #1: 0-24V4A adjustable power supply, text in Finnish

0 to 30 Volt Lab Supply

Variable voltage power supply using LM317HV: Using LM317HV adjustable 3-terminal positive voltage regulator can be designed a very simple high current variable power supply circuit.

1.2 Volt Reference: National Semiconductor Application Notes,04-Nov-1995

12 Volt 30 Amp Power Supply: uses a single 7812 IC voltage regulator and multiple outboard pass transistors, this power supply can deliver output load currents of up to30 amps

12 Volt Alarm Power Supply

12 Volt DC Power Supply

12 Volt RMS to 10 Volt Voltage Regulator: will take a12V RMS sinusoidal input from a transformer and provide a10-Volt DC output at100 mA with very good regulation

12 Volt to 9 Volt DC Converter: Car Converter for12 Volt to 9V

12-V Amplifier Is Designed Using Low-Voltage Digital Potentiometer:02/19/01 Electronic Design - Ideas for Design / Analog circuits today are typically biased from ±5 V to ±18 V. But the trend is toward lower voltages. For this reason, many components are designed to operate primarily in ±5-V systems. One example is the digitally controlled.

13.8 Volt 20PSU: This is a Regulated DC power supply with short circuit protection and with current limiter.

Variable Regulated Power Supply 1.2 to 30 Volts with 1.5 Amps using LM350T

5 Volt Power Supply

78xx Regulator Board: circuit board and circuit for making voltage regulators based on 78xx ICs, in PDF format, text in Finnish

9 Volt 2PSU: A simple 9 Volt 2 amp supply using a single IC regulator.

9  Volt Stabilized Power Supply

Active Preloading Provides Sinking Capability: 01/02/97 EDN-Design Ideas -- A simple add-on circuit enables a unipolar power supply, usually a current-sourcing circuit only, to sink current from a load

Adjustable 3Terminal Regulator for LowCost Battery Charging Systems: National Semiconductor Application Notes, 28-Jun-1996

Adjustable LNB power supply is DiSEqC-compatible: 04/20/98 Electronic Design - Ideas for Design / The circuit shown provides a digitally switchable 13 V or 17 V for the low-noise block (LNB) typically found in satellite receivers at the antenna feedhorn.

Adjustable Power Supply: well filtered variable1.2-30 volts at5 amps using LM338K

Adjustable power supply

Adjustable Power Supply using LM317: voltage regulator for1.2V to35-Volt output voltages and up to1A load

Alarm PSU 

Applications for An Adjustable IC Power Regulator: National Semiconductor Application Notes,04-Nov-1995

Automatic Local Sensing Improves Regulation: 1/04/96 EDN-Design Ideas

Bench Top Power Supply, Auto-Fan

Bench Top Power Supply, Part 1

Bench Top Power Supply, Part 2

Bench Top Power Supply, Part 3

Bench Top Power Supply, Part 4

Capacitance Multiplier Power Supply for Class a Amplifiers

Car Battery Charger: quickly and easily charge most any lead acid battery, automatically turns charging off when ready

Car Converter for 12 Volt to 9V

Car NiCd Charger: This circuit provides up to20-Volt output from a regular13.2V automotive battery, to enable constant current charging of NiCd battery packs up to15 cells @1.2V (18V total).

Change Improves Regulators’ Reliability: 05/12/94 EDN-Design Ideas

Circuit improves on bias for GaAs FETs: 12/06/2001 EDN - Design Ideas / It's important to properly sequence the bias applied to an RF/microwave GaAs FET or a MMIC (monolithic-microwave-IC) amplifier. These devices are extremely sensitive to drain and gate voltage levels as well as to the order in which these biases turn on and off.

Circuit Measures Small Currents Referenced To High-Voltage Rails:01/07/02 Electronic Design - Ideas for Design / Designs that need to measure small signals riding on high-voltage power rails suggest the use of isolation devices.

Circuit provides reference for multiple ADCs:01/24/2002  EDN - Design Ideas / The achievable accuracy for systems with multiple ADCs depends directly on the reference voltages applied to the ADCs. Medical-ultrasound-imaging systems, for example, commonly include a large number of ADCs in the system's beam-former electronics, with the ADCs usually organized in groups of 16, 24, 32, and so on.

Combine A Hot-Swap Circuit With A Linear Regulator: 11/08/99 Electronic Design - Ideas for Design /  Some applications require both a hot-swap circuit to limit inrush currents and a linear regulator to maintain a constant output voltage from minimum to maximum load current.

Constant Current Battery Charger

Current-sensing LDO voltage regulator: 04/20/98 Electronic Design - Ideas for Design / When designing battery-operated devices, battery contact chatter can be prove to be a difficult problem to overcome. When the chatter occurs at a critical time, the results can often be devastating. For instance, if a memory write takes place during a. . .

DAC & OpAmp Provide Variable Control Voltage: 12/06/01 EDN-Design Ideas / PDF contains multiple circuits - scroll to find this circuit

DC Adapter Power Supply: DC voltage "virtual earth" circuits

Digitally Adjust Regulator's Output Using A JFET Interface: 04/29/02 Electronic Design - Ideas for Design / Often, electronic systems are guaranteed to operate with any supply voltage, within a given VCC range. Testing these circuits requires a regulated voltage supply that can be automatically incremented, from a minimum to a certain maximum.

Drawing Power From a PC Serial Port: This circuits derives fairly low power, (mA at5V) from a RS-232 serial connection. (NOTE: ASCII drawing)

Dual + /  15 Volt Power Supply: suitable for powering OpAmp circuits

Dual 12V Power Supply:

Dual Polarity Power Supply 1: supply is easy to build and adjustable from0-15 volts

Dual Regulated Power Supply

Dual Tracking Power Supply

Explanation & Experiment About Regulated DC Power Supply: many power supply designs for different voltages, built from discrete components

Extend the input range of a low dropout regulator: 10/17/2002  EDN - Design Ideas /   Because of process limitations, all ICs have an input-voltage limitation. This limitation can be cumbersome when you try to step down a high supply voltage to a lower, regulated voltage using a dc/dc converter, such as a linear regulator. Adding a FET to the input of a linear regulator creates a dc/dc converter with a wider input-voltage range than the range of the regulator alone

Finesse Regulator Noise:

Fixed Voltage Power Supply:

Get Low-Impedance Scaled Voltages With Everyday Parts: 02/17/03 Electronic Design - Design Briefs / The precise combination of common, inexpensive components can yield a scaled regulated voltage with a very low output impedance and high current output capability. It's especially useful when the output is scaled to one-half of the input value to. . .

Get Power Out of PC Parallel Port: An article which includes circuits, shares how to us a parallel port to connect to a very wide selection of devices like software protection dongles, removable disks, modems, network adapters, printer sharing units, parallel port extenders, soundcards, electronic telecard readers and many circuits.

High Current Power Supply:

High Stability Regulators: National Semiconductor Application Notes,28-Jun-1996

High Efficiency Regulator has Low Dropout Voltage: National Semiconductor Application Notes,01-May-1998

Hot swap higher voltage supplies: 04/19/99 Electronic Design - Ideas for Design /  Some applications, such as communications, fault-tolerant computer systems, and networking, require circuit boards to be inserted into a backplane without turning the power off. The bulk supply. . .

Hot swap structure offers improved redundancy: 01/09/03  EDN-Design Ideas / For redundancy purposes, a number of power supplies, using ORing diodes, can work into the same load. During maintenance, when you can remove any power supply, the minimum possible power perturbation at the load is desirable. To compensate for the voltage drop across the ORing diodes, you must connect the power-supply feedback lines after the diodes, at the load...

IC Provides OnCard Regulation for Logic: National Semiconductor Application Notes,04-Nov-1995

IC Voltage Reference has 1 Ppm Per Degree Drift: National Semiconductor Application Notes,04-Nov-1995

Improving Power Supply Reliability With IC Power Regulators: National Semiconductor Application Notes,04-Nov-1995

Increasing Regulator Current: you can boost 78xx regulator output with1-power transistor

L200 Regulator Circuit: easy to power supply with1-single L200 IC, offers a variable current limit of up to2 A, as well as voltage regulation

Lantern Flasher / Dimmer:

LDO Circuit Provides Smart Power Monitoring: 10/24/96 EDN-Design Ideas

LDO Regulator Works With VOUT Lower Than Its Internal VREF: 12/18/03 Electronic Design - Design Briefs / The reference voltages of standard low-dropout (LDO) linear regulators are usually in the 1.2- to 1.25-V range. But that's not low enough to meet the latest CPU and logic voltage requirements, which can be as low as 0.9 V. That is, the reference. . .

Light Bulb Voltage Regulator

Linear Brief 41 Precision Reference Uses Only Ten Microamperes: National Semiconductor Application Notes,02-Mar-1999

Linear Regulator Converts 3.3 to 2.9V: 03/16/95 EDN-Design Ideas

Linear regulator=low cost dc/dc converter: 06/13/2002  EDN - Design Ideas / The circuit in Figure 1 is a good choice if you need a power supply with high efficiency and you don't want to use expensive dc/dc-converter ICs. The heart of the circuit is IC1, the common, inexpensive LM7805 linear regulator. The external switch is a pnp transistor; the circuit can easily source more than 1A output current..

Linear Regulators Theory Of Operation & Compensation: National Semiconductor Application Notes,24-May-2000

LM105An Improved Positive Regulator: National Semiconductor Application Notes,04-Nov-1995

LM125 Precision Dual Tracking Regulator: National Semiconductor Application Notes,24-Feb-1999

LM317 Adjustable Power Supply:

LM317 Regulator Circuit:

LM317 Regulator With Pass Transistor:

LM317 Variable Power Supply:

LM317 Variable Voltage Regulator:

LM340 Series Three Terminal Positive Regulators: National Semiconductor Application Notes,04-Nov-1995

Logic PSU With Overvoltage Protection: 5 volt regulated power supply for TTL and 74LS series integrated, includes output overvoltage fault protection

Low Battery Detector Preregulates Input Voltage: 08/15/96 EDN-Design Ideas

Low Drop Regulator (postscript File): 

Low Voltage, High Current Time Delay Circuit

Low-Dropout Current Regulator Improves LED Driver Efficiency: 11/06/00 Electronic Design - Ideas for Design / With the proliferation of batterypowered designs, efficient power management becomes crucial in maximizing battery life. Although light-emitting diodes (LEDs) consume a large portion of the battery current in many applications, they’re necessary and. . .

Measurement Circuit Features High CommonMode Rejection : 07/22/02 Electronic Design - Ideas for Design / Modern measurement systems often operate with single 5-V power supplies, yet their input signals may have large common-mode voltages that exceed the supply by tens or hundreds of volts. Also, unless the converter is driven differentially, the noise on...  

Micropower Voltage Reference: National Semiconductor Application Notes,28-Jun-1996

MOSFET Circuit UPS Regulator's Output Current: 02/01/96 EDN-Design Ideas / Use a current mirror and a power MOSFET to increase the output-current capability of an IC-voltage regulator

MOSFET switch provides efficient AC / DC conversion: 02/17/00 EDN-Design Ideas

Negative Regulator has <0.4 Volt Dropout Voltage: 11/06/97 EDN-Design Ideas

Nine-Volt Stabilized Power Supply:

OpAmp Makes Precise 9 Volt Battery Splitter: 07/17/97 EDN-Design Ideas / Alkaline 9V batteries are ideal for many portable, handheld applications, this circuit generates a bipolar supply of5V and ­2.3 to ­4V using a precision5V reference and one op amp as a supply splitter

Pass Regulator's Output Ranges From 0 to 20V: 04/13/95 EDN-Design Ideas

Pass Transistor Lowers Dropout Voltage: 02/18/99 EDN-Design Ideas / PDF contains multiple circuits - scroll to find this circuit

Portable CD Player Adapter for Car: steps down the12V from the lighter socket to 9V which is used by some CD players (Sony Discman)

Positive regulator makes dual negative output converter: 06/26/03  EDN-Design Ideas / Some systems, such as optical networks, require more than one negative voltage. A common procedure is to boost the main negative supply of 5V to 10V and then reduce it with a linear regulator to 9V. The 5V itself comes from a positive supply, typically 5 or 12V. Independently creating each of the two negative voltages requires the use of two switching-regulator ICs...

Positive regulator makes negative dc/dc converter: 12/26/2002  EDN - Design Ideas /  Power-supply designers can choose from a plethora of available positive buck regulators that can also serve as negative boost dc/dc converters. Some buck regulators have a negative-feedback reference voltage expressly for this purpose, but ICs that have positive-reference feedback voltages far outnumber these negative-feedback regula

Power Supply Circuit Tracks Control Input: 12/21/95 EDN-Design Ideas

Power Supply Circuit Tracks Control Input: 12/21/1995 EDN-Design Ideas/

Power Supply Converted from a PC (link):

Power Supply Cuts Switching Noise In DDR Memory Systems: 11/11/02 Electronic Design - Ideas for Design / This design idea describes a unique, low-cost power-supply circuit for a double-data-rate (DDR) memory system. Conventional designs for DDR memories consist of a dual buck converter and a voltage reference. In contrast, this design replaces one buck. . .

Power Supply Provides +5 Volt DC Regulated, +10 Volt DC unregulated & 7.5Volt AC– Hand Drawn:

Power Supply Write-Protects SmartVoltage Memories: 11/03/97 Electronic Design - Ideas for Design /  Second-generation FlashFile memory devices developed by Intel, which employ the company’s SmartVoltage technology, can operate with a 5-V Vpp supply in addition to the established 12 V Vpp. This dual-operating voltage causes a. . .

Power Supply's Output Tracks Negative Input By One-Half: 04/26/04 Electronic Design - Design Briefs / In some fiber-optic communication applications, the Tran impedance amplifier needs a negative bias voltage that tracks the negative input rail by one-half for the data signal's common-mode input range.

Power-Supply Failure Alarm

Protection Feature Enhances Boost Converter: 10/27/94 EDN-Design Ideas

References for a / D Converters: National Semiconductor Application Notes,04-Nov-1995/

Regulated DC Power Supply: many power supply designs for different voltages, built from discrete components

Regulator Excels in Noise & Line Rejection: 01/02/97 EDN-Design Ideas /  Certain electronic circuits require extremely low-noise power supplies and this circuit provides very good quality power output

Regulator Generates SubBandgap Voltages: 01/02/97 EDN-Design Ideas --100-mA regulator that uses a dual linear-regulator IC to produce output voltages below1.25V from2.9 to5.5V input-voltage range

Regulator Makes Dual Tracking Reference: 11/07/96 EDN-Design Ideas

Renkus Heinz Controller Power Supply: outputs regulated +-15-Volt

Shunt Regulator Provides overvoltage Protection: 01/15/98 EDN-Design Ideas

Simple Regulator has one Active Part: 03/16/95 EDN-Design Ideas

Simple Regulator Monitors its Input Voltage: 09/12/97 EDN-Design Ideas

Supply Saves Circuits From Lax Predecessors: 11/23/94 EDN-Design Ideas

Terminal Regulator Is Adjustable: National Semiconductor Application Notes,08-Nov-2000

Transformer less Power Supply: Important Warning: This is a power supply project without using a power supply. This can save the expense of buying a transformer, but presents potentially lethal voltages at the output terminals. Under no circumstances should a beginner attempt to build such a project.

Transistor quickly Wakes Sleeping LDO: 09/01/98 EDN-Design Ideas

Two ACels Power Step Down Regulator: 01/07/99 EDN-Design Ideas /  PDF contains multiple circuits - scroll to find this circuit.

Universal DC to DC Converter

Variable 3 to 24 Volt / 3 Amp Power Supply: regulated power supply can be adjusted from3 to25 volts and is current limited

Variable DC Power Supply:  Voltage range:0.7-24 Volt Current limiting range:50mA-2A

Variable DC Power Supply: based on versatile L200 voltage regulator, independent voltage (3-15V) and current (10mA-2A) limits

Variable Dual Lab Power Supply: can supply from +/-1.2V up to about +/-25V, will current limit at around 800mA

Variable load tests voltage sources: 07/19/2001 EDN - Design Ideas / The circuit in Figure 1 serves as a variable, current-sink load for testing voltage sources. You use digital commands to set the load current of the device under test over a wide range, independently of the device under test's output voltage.

Variable Power Supply, 1 30 Volt@ 1.5A: 1.2 volts to30 volts at1.5 amps

Variable Voltage & Current Power Supply:

Varying Brightness AC Lamp: SCR is used to slowly vary the intensity of a120 volt light bulb by controlling the Time that the AC line voltage is applied to the lamp during each half cycle

Voltage Inverter #2: simple and inexpensive circuit can produce a dual (positive and negative) voltage from a single supply input, extremely useful for powering OpAmp and other circuits that require a dual voltage from a single battery

Voltage Reference improves JFET: 10/26/00 EDN-Design Ideas / PDF contains multiple circuits - scroll to find this circuit

Voltage Regulator: simple regulated12V power supply using1-transistor regulator circuit

Voltage Regulator goes Digital: 11/24/99 EDN-Design Ideas /  PDF contains multiple circuits - scroll to find the one of interest / Power consumption and failing batteries are key issues in battery-operated applications. Features in the new generation of series voltage regulators address these concerns. For example, National Semiconductors LP2951 MicroPower voltage regulator provides a logic-level output signal indicating a low regulated output voltage; the IC also has a logic-level input to shut down the regulator to conserve power.

Wide-Range Programmable Negative Regulator Conserves Power: 06/08/98 Electronic Design - Ideas for Design /  The circuit described here supplies 0 V to −40 V for those applications that require a variable programmable power supply, such as in automated testing systems, battery-discharge-curve simulation, and when driving heating elements to various.

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