Electronic Circuits and Tutorials
Electronics Schematics - P

Power Supplies:  DC to DC / Switch Mode DC to DC Converters, SMPS Circuits

+9 Volt*and*  9 Volt From One Battery!: The MAX1044 is a charge pump converter - it uses a capacitor as a "bucket" to pump charge from one place to another. It can be used to generate negative voltage easily.

10 to 30K Volt Flyback Power Supply:

1118 Simple Regulator Provides ±12 Volt From 5 Volt Source: National Semiconductor Application Notes,31 Aug2001

1119 Voltage Doubler Design & Analysis: National Semiconductor Application Notes,26 Jun2001

20 Watt Simple Switcher Forward Converter: National Semiconductor Application Notes,01 May1998

3.3 Volt Converter Delivers 3 Watt From Li ion Battery: 11/05/98 EDN-Design Ideas

3.3 Volt Lithiumcell Supply Requires one inductor: 08/05/99 EDN-Design Ideas / PDF contains multiple circuits - scroll to find this circuit.

3.3 Volt Supply Taps Power From the12  Volt PCI Bus:

5 to 1.8 Volt Converter Works Without Magnetics: 04/13/00 EDN-Design Ideas / PDF contains multiple circuits - scroll to find the one of interest /

5 Volt DC From RS232 Signals: The circuit of Figure1 produces a semi-regulated5-Volt output from an RS-232 port. Unlike a PC-mouse supply or comparable that rely on the modem-control signals DTR and RTS, this one operates with a3-wire port GND, Rx, and TX, and obtains power only from the TX line. The output current-about 8mA-is sufficient for CMOS microcontrollers and other low power.

5 Volt Supply Derives Power From Three Wire RS232C Port: 10/26/95 EDN-Design Ideas

6 to 12 Volt Converter: This circuit can provide up to 800mA of12V power from a 6V supply. The circuit is simple, about 75% efficient and quite useful.

60 MCurrent Source Feeds Telecomm Lines: 12/18/97 EDN-Design Ideas

8Switcher Powers High Performance µPs: 04/13/95 EDN-Design Ideas

Add Trimmable Current Limit to DC to DC Supply: 08/01/97 EDN-Design Ideas /  you can add a simple, two-transistor circuit to a standard, step-down dc/dc converter to provide an adjustable limit for the output current

AutoTransformer Regulator Inverts 12 Volt to Produce ­12V: 08/01/97 EDN Design Ideas / Produces Output of200 mA

Battery Backup Converter uses One NiCd Cell: 02/03/97 EDN Design Ideas / This dc/dc Converter allows you to replace a five or six unit string of NiCd coin Cells with one Cell

Battery Booster Delivers 75W: 07/16/98 EDN Design Ideas / Uses isolated DC/DC Converter in a nonisolated configuration to boost a48V Battery voltage to 60 Volt

Boost Controller Drives Buck Converter: 02/03/97 EDN Design Ideas / By adding an external Switching Transistor, you can use a step up dc/dc Converter to step down voltages to produce an efficient Battery Powered Power Supply, this example Circuit can step down inputs as Low as2V to Outputs as Low as1.25V, with efficiency as high as 80%

Boost Converter Generates ­27 & ­87V: 05/22/97 EDN-Design Ideas / Generates the voltage levels necessary for standard telephones from12V

Boost Converter Generates Three Analog Rails: 07/02/98 EDN-Design Ideas

Bootstrapped Boost Converter operates At 1.8 Volt : 04/23/98 EDN-Design Ideas

Bootstrapping allows single rail op amp to provide 0V output: 02/06/03  EDN-Design Ideas / Many single-supply-powered applications require amplifier-output swings within 1 mV—or even sub-millivolts—of ground. Amplifier-output-saturation limitations normally preclude such operation. Figure 1's power-supply bootstrapping scheme achieves the desired characteristics with minimal parts count

Buck regulator and two inductors make dual polarity converter: 03/20/03  EDN-Design Ideas / A common problem for power-supply designers is to create a compact, dual-polarity step-down converter. If space and cost are not concerns, the obvious solution is a pair of dc/dc converters, one for each output.

Buck Regulator Generates Flexible VTT for PECL: 08/15/97 EDN Design Ideas / Circuit to generate Output which can both Source and Sink Current

Buck regulator operates without a dedicated clock : 08/21/03  EDN-Design Ideas / Most switching regulators rely on a dedicated clock oscillator to determine the switching frequency of operation. A dedicated oscillator circuit within the power controller usually generates the clock signal.

Buck Regulator Terminates Fast Data Buses: 07/20/95 EDN-Design Ideas

Buck Regulator uses Step up Controller: 11/09/95 EDN-Design Ideas

Capacitor Charger Improves High Voltage Supply: 12/19/96 EDN-Design Ideas

Capacitor improves efficiency in CPU supply: 04/04/2002  EDN - Design Ideas / High efficiency is important for the dc/dc buck converters that supply high currents in notebook PCs. This efficiency extends battery life and minimizes temperature rise. A low-dissipation synchronous rectifier using an external MOSET provides this high efficiency.

Circuit Drives 9 Volt Solenoids From 3 Volt Battery: 08/17/95 EDN-Design Ideas

Circuit Multiplexes Automotive Sensors: 01/20/00 EDN-Design Ideas / PDF contains multiple circuits - scroll to find this circuit.

Circuit Provides 1.5V, 7Bus Termination: 09/14/95 EDN-Design Ideas

Circuit reduces negative voltage stresses on control IC: 04/18/2002  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 to some voltage lower than ground.

Circuit Variations Produce Negative Voltages: 09/01/00 EDN-Design Ideas / PDF contains multiple circuits - scroll to find the one of interest / This circuits easily configures basic switched-capacitor converters to also do some negative conversions

Clean Switcher Powers 16 Bit a / D Converters: 07/04/94 EDN-Design Ideas

Coilless Step up Converter yields Dual Outputs: 09/01/97 EDN-Design Ideas 

Comparator Adds Current Limit to V2 Controller: 05/21/98 EDN-Design Ideas

Comparator Improves Regulator's Efficiency: 04/28/94 EDN-Design Ideas

Converter Generates 3.3 Volt From Two or Three Cells: 11/11/96 EDN-Design Ideas

Converter has High Efficiency At Low Loads: 01/06/94 EDN-Design Ideas / MicroPower components and circuit design of this converter enable it to maintain 90% efficiency for load currents below 8 mA, circuit outputs5V DC

CoolSET TDA16831:  -34 for OFF-Line Switch Mode Power Supplies

Cuk Converter yields 90% Efficiency: 09/01/94 EDN-Design Ideas

Current Limit Protects Power Bus: 12/12/97 EDN-Design Ideas / Protects a power bus from a load short within a guaranteed2 µsec response Time

Current Source Forms unusually Simple Regulator: 09/12/97 EDN-Design Ideas / Simple regulator uses a switching current source to drive a pair of shunt Zener regulators, circuit produces ±15V dual outputs, for total output power of approximately400 mW form100-400-Volt DC source

DC to DC Controller Generates Negative Supply: 06/08/95 EDN Design Ideas / a Switch mode Power Supply Controller plus a diode capacitor network generate the modest negative Supply Current needed for OpAmps or for LCD Bias, without inductors

DC to DC Converter Allows of Single Battery: Have you ever wanted to circuit to run off a single 9 Volt battery only to find you needed levels like +12 and -12 Volts? The thought of multiple batteries might have put you off. Why not use a simple DC to DC converter?

DC to DC Converter operates From Phone Line: 11/09/00 EDN Design Ideas / PDF contains multiple circuits - scroll to find this circuit

DC to DC Converter: will produce a 85-Volt voltage from +3V, usable for low power applications

DC/DC Conversion Without Inductors: Maxim Application Note #725

Designing a Multi Phase Asynchronous Buck Regulator using the LM2639: National Semiconductor Application Notes,27 Mar2000

Drive High Voltage Varactor Diodes From just 5V: 03/27/97 EDN-Design Ideas

Easy Xenon DC to DC Converters!:

Flyback Circuit Provides Isolated Power Conversion: 01/07/99 EDN-Design Ideas / PDF contains multiple circuits - scroll to find this circuit.

Half Bridge Inverter has Variable Frequency: 10/09/97 EDN-Design Ideas

Handy tool Troubleshoots Feedback Loops: 04/10/97 EDN-Design Ideas 

Hex Inverter Makes Low Cost Switching Regulator: 05/23/96 EDN-Design Ideas / Simple and low-cost circuit converts5V to12V

IC & Capacitor Improve Isolated Supply: 09/01/97 EDN-Design Ideas

Ignition Coil / Flyback Transformer Based High Voltage Generators: This page gives my thoughts on how to use a car ignition coil or Flyback transformer as a high voltage generator. The objective is to produce as high a voltage as possible, with as high a power throughput as possible.

Inverter Forms High Efficiency Rail Splitter: 08/01/97 EDN-Design Ideas / switched-capacitor voltage inverter can be used as "rail splitter" to provide bipolar, dual-rail power supply

Isolated Signal Trims DC / DC Converter: 09/01/95 EDN-Design Ideas

Isolated Telecomm Converter Handles 25W: 09/01/97 EDN-Design Ideas /  Telecomm applications in the central office require an isolated5V supply derived from ­48V, this gives out5V at5A from an input voltage of ­36 to ­72V

LAN Power Supply Generates Isolated 9V: 04/11/96 EDN-Design Ideas

Layout Guidelines for Switching Power Supplies: National Semiconductor Application Notes,24 May2001

LH1605 Switching Regulator: National Semiconductor Application Notes,04 Nov1995

Li ion Boost Circuit uses No inductors: 09/12/97 EDN-Design Ideas / Circuit to maintain regulated3.3V supply for portable applications

LIER Circuit helps Power Supply Efficiency: 02/16/95 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 supply uses switch mode regulation: 07/19/2001 EDN - Design Ideas / You can use simple circuits to implement small, regulated plug-in power supplies. In Figure 1 , a basic and versatile 5V supply uses a Zener diode and an emitter-follower transistor. You must calculate and design the transformer such that Q 1 is close to saturation at low mains voltages and nominal output current.

LM2577 Three Output, Isolated Flyback Regulator: National Semiconductor Application Notes,01 May1998

LM2651_3.3V_EVAL 1.5High Efficiency Synchronous Switching Regulator Evaluation Board: National Semiconductor Application Notes,14 Sep1999

LM2675 5.0EVAL 1 Amp Step Down High Efficiency Simple Switcher Evaluation Board: National Semiconductor Application Notes,10 Feb1999

LM267X 3A, 5Evaluation Boards: National Semiconductor Application Notes,20 Jul1999

LM78S40 Switching Voltage Regulator Applications: National Semiconductor Application Notes,02 Mar1999

Low Cost Circuit Biases VCOs for Cable & TV: 11/20/97 EDN-Design Ideas /  PLLs are useful in a variety of applications, most notably cable and TV tuners

Low cost feedback circuit boosts efficiency: 01/21/99 EDN-Design Ideas /  PDF contains multiple circuits - scroll to find this circuit

Low Cost Switcher Converts 5 to 24V: 02/16/98 EDN-Design Ideas / Low-cost, three-transistor low power boost switching regulator

Low Cost, Low Parts Count DC / DC Converter With Multiple Outputs: National Semiconductor Application Notes,02 Mar1999

Low Noise Step up Supply Generates ­5.5 Volt Output: 10/09/97 EDN-Design Ideas

Low Power Converter has Galvanic Isolation: 07/02/98 EDN-Design Ideas / This simple dc/dc converter provides a12V,150-mW output using only a few components and a small transformer, CD4049 forms an oscillator that operates at approximately200 kHz and runs the converter, regulated output

Lower dc/dc converter ripple by using optimum capacitor hookup: 10/31/2002  EDN - Design Ideas / Low-ripple-voltage positive-to-negative dc/dc converters find use in many of today's high- frequency and noise-sensitive disk drives, battery-powered devices, portable computers, and automotive applications.

Maximizing Start up Loads With the LM3352 Regulated Buck / Boost Switched Capacitor Converter: National Semiconductor Application Notes,15 Sep1999

Memory Supply Includes Battery Backup: 02/03/97 EDN-Design Ideas

Notebook Power Supply has Two Outputs: 03/03/94 EDN-Design Ideas

Off Hook Phone Line Supplies 150 MW: 11/09/00 EDN-Design Ideas / PDF contains multiple circuits - scroll to find the one of interest09/01/94 EDN Design Ideas / Circuit draws Current in the off hook condition, delivering as much as150 mW of isolated poser while allowing normal voice or Data communications over the phone line

Off Line Buck Regulator Cuts Costs, Lead-time: 10/26/95 EDN-Design Ideas

Off Line Power Supply Requires Few Parts: 02/17/94 EDN-Design Ideas / This simple non-isolated off-line power supply can provide up to150 mA5V and uses only a handful of components from110-230-Volt AC input voltage. Note that the low voltage output is directly connected to the mains; it cannot be used when the low voltage part can be touched.

One 9 Volt Battery gives +18, +25, +33V: This circuit is based on MAX1044 is a charge pump converter.

Open Loop Power Supply Delivers As Much As One Watt: 01/18/01 EDN-Design Ideas / PDF contains multiple circuits - scroll to find this circuit- For VCRs, TVs, and other equipment that requires a standby mode, you must supply power to a µP when other components are asleep. Any active power-supply circuit also needs to be more cost- effective than the standard structure using a metallic transformer. This circuit is simple switcher that takes230-Volt AC and outputs10-Volt 90mA

PFM Control Improves Dual Output Converter: 09/28/95 EDN-Design Ideas

Plus 5 to Minus 15 Volts DC Converter: National Semiconductor Application Notes,28 Jun1996

Power Supply Runs off Battery or Wall Adapter: 06/18/98 EDN-Design Ideas

Power Switch Provides Soft Start: 03/30/00 EDN-Design Ideas /  PDF contains multiple circuits - scroll to find the one of interest /

Precharged Capacitor Ensures High Side Start up: 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

Programmable Source Powers DC Micro Motors: 03/01/01 EDN-Design Ideas / PDF contains multiple circuits - scroll to find the one of interest / 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

Pulsing Charge Pump Drives Capacitive Loads: 11/05/98 EDN-Design Ideas

Push Pull Driver Provides Isolated 5 Volt At 1A: 03/30/00 EDN-Design Ideas / PDF contains multiple circuits - scroll to find the one of interest / Regulated5V input to an isolated5V output with1A current-output capability

Quickly discharge power supply capacitors: 07/05/2001 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.

Regulator Generates As Many As Four Voltages: 08/03/95 EDN-Design Ideas

Saturable Bead Improves Reverse Recovery: 02/03/97 EDN-Design Ideas

SEPIC Generates 5 Volt At 100 MA: 05/03/01 EDN-Design Ideas / PDF contains multiple circuits - scroll to find the one of interest / Some applications require an input voltage higher than the breakdown voltage of the IC supply pin. In boost converters and SEPICs (single-ended primary-inductance converters), you can separate the VIN pin of the IC from the input inductor and use a simple Zener regulator to generate the supply voltage for the IC. This design shows a SEPIC that takes a4 to28V input and generates5V at100 mA.

Serial Interface IC Supplies BiPolar Voltages: 07/06/95 EDN-Design Ideas

Simple Boost Converter Generates ­27 & ­87V: 05/22/97 EDN-Design Ideas

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

Simple Regulator Provides ±12V: 10/23/97 EDN Design Idea / Simple circuit can provide ±12V from a5V input using only one switching-regulator IC and a few off-the-shelf

Single cell lights any LED: 07/05/2001 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 in LED-based flashlights, such as a red LED in an astronomer's flashlight, which doesn't interfere with night vision.

Single IC Biases LCD & GaAsFET Amplifier: 04/09/98 EDN-Design Ideas

Single NiCd Cell Drives OpAmp: 12/05/96 EDN-Design Ideas

Single Resistor Improves V2 Converter: 08/15/97 EDN-Design Ideas /  V2 control offers a significant improvement in transient response by using two voltage feedbacks, example circuit is for generating voltages in1.8-3.3V range

Solar Cell Converter offers Positive Start up: 11/09/00 EDN Design Ideas / PDF contains multiple circuits - scroll to find this circuit

Step up / Step Down Converter Takes 2 to 16 Volt Inputs: 11/09/00 EDN Design Ideas / PDF contains multiple circuits - scroll to find the one of interest / - Switcher where input can range above and below the regulated voltage, Circuit accommodates a wide range of input and Output voltages and supplies Output Currents as high as500 mA

Step up Regulator uses only Two Gain Devices: 11/09/00 EDN Design Ideas / PDF contains multiple circuits - scroll to find this circuit

Step up Supply Charges Battery While Serving Load: 11/09/00 EDN Design Ideas / PDF contains multiple circuits - scroll to find this circuit

Supply derives 5 and 3.3V from USB port: 12/20/2001 EDN - Design Ideas / The circuit in Figure 1 derives its power from a USB port and produces 5 and 3.3V supply rails for portable devices, such as digital cameras, MP3 players, and PDAs. The circuit allows the port to maintain communications while, for example, charging a lithium-ion battery. IC2 boosts the battery voltage, VBATT, to 5V, and IC3 buck-regulates that 5V output down to 3.

Switch Mode DC Supply: The switching power supply, shown in the schematic, provides12 volts, at10 amps, maximum, using a discrete transistor regulator with an op-amp functioning as a comparator in the feedback circuit. The supply was constructed in1984 and is variable frequency, as opposed to the pulse width modulator (PWM) controllers used today.

Switched capacitor Regulator Provides gain: 03/13/98 EDN-Design Ideas / PDF contains multiple circuits - scroll to find this circuit

Switcher IC hikes Battery Charger's Efficiency: 06/23/94 EDN-Design Ideas

Switching Converter uses Planar Magnetics: 11/07/96 EDN Design Ideas

Switching regulator forms constant current source: 05/30/2002  EDN - Design Ideas /  Many applications require current sources rather than voltage sources. When you need a high-current source, using a linear regulator is inadvisable, because of the high power dissipation in the series resistor. To solve the wasted-power problem, you can use a switch-mode regulator. The circuit of Figure 1 uses IC1, an LM2576 adjustable regulator..

Switching Regulator Output goes Below VREF: 03/17/94 EDN-Design Ideas

Synchronized Regulator Produces Coherent Noise: 03/17/94 EDN-Design Ideas

Synchronous buck circuit produces negative voltage: 03/06/03  EDN-Design Ideas / Many electronic systems require both positive and negative voltages to operate properly. Generating an efficient, low-voltage positive output from a higher voltage input typically entails the use of a synchronous buck regulator. But when generating a negative output voltage from a positive input voltage.

System Oriented DC to DC Conversion Techniques: National Semiconductor Application Notes,01 May1998

Three Input Supply Powers 3.3 Volt Portables: 10/26/00 EDN Design Ideas / PDF contains multiple circuits - scroll to find the one of interest-- Single ended primary inductance Converter accepts input voltages ranging from3 to more than 6V and produces a regulated3.3V,200 mA Output

Tiny Tiny Inverter Design: little efficient circuit that runs off of3V, and charges up a little1 uf250-Volt cap all the way up in about30 seconds

Transformer Buys Lower Shutdown Current: 11/23/94 EDN-Design Ideas

Transformer less Supply Fits CaT Volt Applications: 05/22/97 EDN-Design Ideas / Coaxial CATV systems derive their power from a 60-Hz square wave that shares the center conductor with the television channels this circuit generates10 mA at5V DC from it

Transistor Pair Lowers PWM IC's Start up Current: 03/18/99 EDN-Design Ideas / PDF contains multiple circuits - scroll to find this circuit

Transistors tame perfidious leakage inductance: 09/27/2001 EDN - Design Ideas / In flyback converters that use primary regulation, the loose coupling between the power secondary and the primary auxiliary windings often results in poor cross-regulation. This situation arises mainly from the leakage inductance but also comes from the level of the primary clamp voltage.

Two ACells Power Step Down Regulator: 10/26/00 EDN Design Ideas / PDF contains multiple circuits - scroll to find this circuit

Two Cores Marry, Make Swinging Choke: 10/26/00 EDN Design Ideas / PDF contains multiple circuits - scroll to find this circuit

Universal High Resistance Voltmeter:

Use a 555 timer as a switch mode power supply: 11/14/2002  EDN - Design Ideas / Most switch-mode power supplies rely on a PWM (pulse-width-modulated) output that is controlled via voltage feedback. A 555-timer IC can inexpensively perform PWM. The circuit in Figure 1 shows how to turn a 555 PWM circuit into an switch-mode power supply with only one simple equation. The design uses two 555s

Use the LM158 / LM258 / LM358 Dual, Single Supply OpAmp: National Semiconductor Application Notes,14 May2001

Wallcube DC / DC Converter is 85% Efficient: 09/12/97 EDN-Design Ideas / Ubiquitous12V wall cube generates an unregulated dc voltage of 8 to18V, depending on line voltage and load, this circuit generates a regulated5V400 mA from it very efficiently

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