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Power Control Circuits
#'s - D      E - Z


 

Last Updated: October 18, 2017 05:04 AM

Circuits Designed by Dave Johnson, P.E. :

Battery Polarity Reversal protects Circuit - This simple circuit can protect a sensitive electronic circuit from an accidental connection of a battery with a reversed polarity.  The N-channel FET connects the electronic device to the battery only when the polarity is correct.  The circuit shown was. . . Circuit by David A. Johnson P.E.-March, 2002

Bi-Directional Charge Coupled Powers MOSFET Relay - The circuit uses an inexpensive C-MOS inverter package and a few small capacitors to drive two power MOS transistors from a 12v to 15v supply.  Since the coupling capacitor values used to drive the FETs are small, the leakage current from the power line . . . Hobby Circuit designed by Dave Johnson P.E.-June, 2000

characteristics of CMOS Logic Inverter Amplifiers - This chart shows some of the measured characteristics of three different unbuffered CMOS logic gates, used as voltage amplifiers . . . Hobby Circuit designed by David Johnson P.E.-February, 2002

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A for mains synchronization has two separate outputs for each half-period-  EDN Design Ideas:  03/22/2013  Generate independent short pulses at positive- and negative-going AC mains zero crossings. __ Circuit Design by Dusan Ponikvar

Analog switch lowers relay power consumption-  20-Dec-01 EDN Design Ideas:  Designers often use relays as electrically controlled switches.  Unlike transistors, their switch contacts are electrically isolated from the control input.  However, the power dissipation in a relay coil may render the device unattractive in battery-powered applications.  You can lower this dissipation by adding an analog switch that allows the relay to operate at a lower voltage (Figure 1) __ Circuit Design by Steve Caldwell, Maxim Integrated Products, Chandler, AZ

Analog switch lowers relay power consumption-  Abstract: Design Idea outlining a method to use an analog switch and discrete components to reduce the power dissipated in relay actuation -- Relays are often used as electrically controlled switches.  Unlike transistors, their switch contacts are electric__ Maxim Integrated APPLICATION   NOTE 956

Automate Switch-Over Between Battery & Source-  12/18/97 EDN Design Ideas:  The use of a logic supply or an ac wall adapter can extend battery life in a small portable system by offloading the battery.  However, managing the switch-over between battery and external power can be messy.  For high-cell-count b __ Circuit Design by Len Sherman, Maxim Integrated Products, Sunnyvale, CA

Automatic control starts loads softly-  10/13/94 - EDN Design Ideas:  Applying ac power to the circuit in Fig 1 causes it to gradually increase the power to the ac load, effecting a "soft start. "  The components connected to 555 timer IC1's pin 2 provide a trigger synchronized with the ac input's zero crossing.  In conventional 555 fashion, R1, R2, and C determine IC1's period. __ Circuit Design by Liu Ning, Institute of Quantum Electronics, South China Normal University, Guangzhou, China

Automatic Power Switch-  This circuit turns a slave device on when a master device is turned off or on depending on  state of S1.  The circuit is designed to be reliably and solidly on or off.  Some simpler slave switches can mistrigger or trigger partially, __ Designed by Andrew R. Morris

Automatic Power-Off Saves Battery-  12/19/96 EDN Design Ideas:  The Basic training program in Listing 1  helps visually handicapped people easily learn Braille dot code with the help of a trainer.  The trainer generates six-pin Braille code using six solenoids operating on an LPT1/2 either by directly connecting the low-power solenoids to the data bits of the parallel port or by driving solenoid pins (pull-out type] using an UN2003 power driver (Figure 1).  Push-in type solenoids require complemented (0 for 1 and 1 for 0] Braille-code data bits or an extra inverter on the LPT1 port __ Circuit Design by Jose Carlos Cossio, Santander, Spain

Automatic Power-Resumption Alarm-  Most power-resumption alarm devices produce non-stop alarm when power resumes.  To overcome this problem, here is an automatic circuit that sounds an alarm for a few seconds only after power resumes....__ Electronics Projects for You

Automatic Pump Shut Off-  Put together an automatic system to switch off a pump when there is no more fluid left to pump. __ Designed by REUK-Renewable Energy UK website

Automatically Switches Off DMM-  08/17/12  EDN Design Ideas:  Add automatic-shutoff to your DMM, save batteries, and eliminate wear and tear on the function switch. __ Circuit Design by Vladimir Oleynik, Moscow, Russia

Autotransformer regulator inverts 12V to produce ­12V-  08/01/1997 EDN Design Ideas:  You can create a dc/dc regulator with an internal switching MOSFET that inverts 12V to produce an output of 200 mA at ­12V.  The IC is a high-efficiency device whose low quiescent current (120 µA maximum) is the product of a CMOS process that limits the absolute-maximum input-to-output voltage to 21V. __ Circuit Design by Dana Davis

Battery Polarity Reversal protects Circuit-  This simple circuit can protect a sensitive electronic circuit from an accidental connection of a battery with a reversed polarity.  The N-channel FET connects the electronic device to the battery only when the polarity is correct.  The circuit shown was. . . Circuit by David A. Johnson P.E.-March, 2002

Battery Saver-  Worth  effort! The Battery Saver is designed to prolong the battery life in small toys and devices by disconnecting the load after a preset period.  The two versions shown switch up to one amp and give about one minute of operation before shutting off __ Contact:  Charles Wenzel of Wenzel Associates, Inc.

Bi-Directional Charge Coupled Powers MOSFET Relay-  The circuit uses an inexpensive C-MOS inverter package and a few small capacitors to drive two power MOS transistors from a 12v to 15v supply.  Since the coupling capacitor values used to drive the FETs are small, the leakage current from the power line . . . Hobby Circuit designed by Dave Johnson P.E.-June, 2000

Build a UPS for USB Devices-  04/11/02 EDN Design Ideas:  Portable systems often include circuitry that derives power from an external source, such as USB.  When the system disconnects from the USB supply, a battery takes over and supplies current via a DC/DC converter.  A diode-OR connection (Figure 1) offers the easiest way to ensure that the supply voltage doesn't sag during this switchover to the battery __ Circuit Design by Mark Cherry and Jean-Claude Ailloud, Maxim Integrated Products, Sunnyvale, CA, and France

characteristics of CMOS Logic Inverter Amplifiers-  This chart shows some of the measured characteristics of three different unbuffered CMOS logic gates, used as voltage amplifiers . . . Hobby Circuit designed by David Johnson P.E.-February, 2002

Circuit Automates Switch-Over Between Battery & Source-  12/18/97 EDN Design Ideas:  The use of a logic supply or an ac wall adapter can extend battery life in a small portable system by offloading the battery.  However, managing the switch-over between battery and external power can be messy.  For high-cell-count b __ Circuit Design by Len Sherman, Maxim Integrated Products, Sunnyvale, CA

Circuit Automatically Switches Off DMM-  08/17/12  EDN Design Ideas:  Add automatic-shutoff to your DMM, save batteries, and eliminate wear and tear on the function switch. __ Circuit Design by Vladimir Oleynik, Moscow, Russia

Circuit breaker handles voltages to 32V-  25-May-00 EDN Design Ideas:  The simplicity of low-side current monitoring can mask the advantages of a high-side approach.  You can monitor load currents in a power supply, a motor driver, or another power circuit on either the high or the low side (ground].  However, don't let the ease of low-side monitoring cause you to overlook __ Circuit Design by Greg Sutterlin and Craig Gestler, Maxim Integrated Products, Sunnyvale, CA

Circuit Breaker Provides Overcurrent & Precise Overvoltage Protection-  7-Jun-07 EDN Design Ideas:  A simple circuit breaker delivers precision overvoltage protection and overcurrent protection __ Circuit Design by Anthony H Smith, Scitech, Bedfordshire, England

Circuit disconnects load-  02/17/00  EDN Design Ideas:  Placing a load-disconnect circuit on the output of a bootstrapped step-up regulator allows the regulator to start with load currents much higher than would otherwise be possible ( Figure 1).  During shutdown, the disconnect completely isolates the battery __ Circuit Design by Larry Suppan

Circuit Disconnects Load From Battery-  03/14/96 EDN Design Ideas:  To prevent battery damage, the circuit in Figure 1 disconnects the load at a predetermined level of load voltage.  This load voltage, VTRIP, is closely proportional to the battery voltage.  R1 and R2 determine the level of VTRIP  that corresponds to voltage of 1.15V at pin 3 of IC1.  A voltage of 1.15V at pin 3 of IC1 causes the internal comparator to trip.  Thus, VTRIP=1.15 (R1+R2) /R1 __ Circuit Design by Michael Keagy, Maxim Integrated Products, Sunnyvale, CA

Circuit Disconnects Load From Low-Voltage Supply-  04/24/03  EDN Design Ideas:  Circuit ensures safety in power-on operation.  Power supplies often include a circuit that disconnects the load when the supply voltage drops too low, such as when a battery is nearly discharged.  A p-channel MOSFET connected between supply and load is the typical approach.  However, a 1.5V single-cell battery or other low-voltage supply is insufficient to fully turn on the MOSFET.  For such low-voltage systems, consider the circuit of Figure 1. __ Circuit Design by Steve Caldwell

Circuit Ensures Safety In Power-On Operation-  04/24/03 EDN Design Ideas:  Buck converter handles battery-backup system - Computers find universal use in industrial-control systems.  During power- and start-up sequences (booting], the outputs of such control systems may yield uncontrolled pulses before the software defines the correct status.  If these outputs control the power-on state of a system, these uncontrolled pulses could have dramatic consequences __ Circuit Design by Jean-Bernard Guiot, DCS AG, Allschwil, Switzerland

CMOS Gate Implements Reverse Phase Control-  05/21/98 EDN Design Ideas:  ( FILE has several circuits, scroll down) The circuit in Figure 1 implements a "reverse" phase control, using only a single CMOS 4001 quad NOR gate.  The circuit is known as a reverse phase control because, unlike with common TRIAC or SCR controls, conduction begins at the zero crossing of the ac sine wave.  Timing of the turn-off point __ Circuit Design by JC Johnson, Lithonia Lighting, Decatur, GA

Controller Provides Constant Power DC Load-  03/14/97 EDN Design Ideas:  Circuits that draw constant power regardless of input voltage usually rely on voltage multipliers or other exotic analog functions.  The constant-power load in Figure 1, though, combines a resistive load with a simple switching po __ Circuit Design by John Wettroth, Maxim Integrated Products, Sunnyvale, CA

Convert 1 to 5V signal to 4-to 20-mA output-  04/19/12  EDN Design Ideas:  Despite the long-predicted demise of the 4- to 20-mA current loop, this analog interface is still the most common method of connecting current-loop sources to a sensing circuit.  This interface requires the conversion of a voltage signal—typically, 1 to 5V—to a 4- to 20-mA output.  Stringent accuracy requirements dictate the use of either expensive precision resistors or a trimming potentiometer to calibrate out the initial error of less precise devices to meet the design goals. __ Circuit Design by Thomas Mosteller, Linear Technology Corp

Correct Voltage Drop & Phase Shift In Transmission Lines-  20-Mar-03 EDN Design Ideas:  Synchronous buck circuit produces negative voltage - Many precision test-and-measurement and high-speed analog applications require an exact targeted voltage to be delivered to the device under test or intended load to accurately analyze the device.  Design and test engineers are well-aware that this goal is sometimes unattainable, because the impedance across the traces delivering the signal to the load alters the original signal __ Circuit Design by Ron Shakery, Texas Instruments, Dallas, TX

Digital Bench Power Supply-  PIC Project  This unit delivers 0 to 20 volts at up to 4 amps in 0.1volt increments.  The entire device runs on a PIC16F870 ( about $3 in small quantities).  This is basically a switching power supply with the voltage regulation done in software.  The PIC used here has analog inputs ( used to measure voltage and current) and hardware PWM ( pulse width modulation) output used to control the power. __ Designed by Luhan Monat-Mesa Arizona

Disconnect Load from Battery-  03/14/96 EDN Design Ideas:  To prevent battery damage, the circuit in Figure 1 disconnects the load at a predetermined level of load voltage.  This load voltage, VTRIP, is closely proportional to the battery voltage.  R1 and R2 determine the level of VTRIP  that corresponds to voltage of 1.15V at pin 3 of IC1.  A voltage of 1.15V at pin 3 of IC1 causes the internal comparator to trip.  Thus, VTRIP=1.15 (R1+R2) /R1 __ Circuit Design by Michael Keagy, Maxim Integrated Products, Sunnyvale, CA

Disconnect Load from Low-Voltage Supply-  04/24/03  EDN Design Ideas:  Circuit ensures safety in power-on operation.  Power supplies often include a circuit that disconnects the load when the supply voltage drops too low, such as when a battery is nearly discharged.  A p-channel MOSFET connected between supply and load is the typical approach.  However, a 1.5V single-cell battery or other low-voltage supply is insufficient to fully turn on the MOSFET.  For such low-voltage systems, consider the circuit of Figure 1. __ Circuit Design by Steve Caldwell

Dome Lamp Dimmer-  A reading light inside the car greatly assists passengers during night, but often the interior dome lamp is too bright and distracting to the driver.  A linear regulator such as a...__ Electronics Projects for You

Dome Lamp Dimmer-  This unique circuit makes your dome light look cool.  Usually when the car door is closed, the dome light just goes OFF.  With this circuit, you can have our dome light fade slowly. __ Contact:  Charles Wenzel of Wenzel Associates, Inc.

Dome light dimmer (with Delay)-  For all you guys out there that want a fading dome light ( aka courtesy light aka theatre lighting) without having to pay for one, you can build your own.  I have attached the schematics and you can build it for a few bucks given that you don't have any spare components lying around otherwise it can cost you absolutely nothing.  Of course you can rip some parts from your TV, CD player, radio, etc.  , but I'm not responsible for the damage you cause this way [b:e43bc460fa]The way it works[/b:e43bc460fa] I won't bother you with technical__

Dome Light Extender-  There are countless dome light extenders on the Net and in magazines, but most of them suffer from one problem complexity.  Ok, they are not actually complex, but most are far more complex than they need to be.  Some are completely over the top, and require additional car wiring, a PCB, ICs, trimpots and lots of other stuff, while others seem to be someone's untested idea or maybe just a brain fart - some circuits I saw will never work.  My goal was extreme simplicity, and I think that has been achieved. __ Designed by Rod Elliott  ESP


Power Control Circuits#'s - D      E - Z

 


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