• Battery Powered Plus-Minus 15v Supply
  Many classic operational amplifier circuits call for a split positive and negative 15 volt supply.  The circuit below makes the job of generating such a supply much easier by using an off-the-shelf DC to DC converter, powered from a cheap 6v battery made from four AA cells.  The converter, part number VESD1-S5-D15-SIP, is available from Digikey, their catalog number 102-1410, for about $6.00.  To insure clean voltages, I follow the output of the converter with two voltage regulators, also available from Digikey.  The result is a very nice supply rated at 30ma from each supply voltage.  This should be plenty of current for most circuits.

• CHARGE PUMP EFFICIENTLY DIVIDES SUPPLY VOLTAGE
  This circuit uses a few FETs and logic devices to down convert a DC voltage to about one half its value.

Basic UPS - (electronic diagram added 6/03)

Battery Backup Converter uses One NiCd Cell - 02/03/97 EDN-Design Ideas: Notebook computers and or portable equipment often use a backup battery to retain memory contents during replacement of  main battery. Such "bridge batteries" usually consist of five or six series-connected NiCd coin cells. They're expected to keep  system alive for approximately 5 minutes—plenty of time to swap batteries.....(design idea added 7/02)

Battery Charger 12v SLA - Before we go into the operation of the SLA Battery Charger circuit, there are a number of points we need to cover about the care and use of Sealed Lead Acid batteries.  Firstly, these batteries must be charged, discharged and stored very carefully.We normally think batteries can be stored for months (if not years) and they will be available for immediate use.....(circuit design added 05/06/07)

Battery Powered Plus-Minus 15v Supply - Many classic operational amplifier circuits call for a split positive and negative 15 volt supply.  The circuit below makes the job of generating such a supply much easier by using an off-the-shelf DC to DC converter, powered from a cheap 6v battery made from four AA cells.  The converter, part number VESD1-S5-D15-SIP, is available from Digikey, their catalog number 102-1410, for about $6.00.  To insure clean voltages, I follow the output of the converter with two voltage regulators, also available from Digikey.  The result is a very nice supply rated at 30ma from each supply voltage.  This should be plenty of current for most circuits. ….(designed by David A. Johnson)

Bench Power Supply - Here is a rar novel Power Supply Unit (PSU) for  workbench which can deliver 0-15 volts and up to 0-3 amperes. I have not shown any mains fuses as this I will leave to your own devices. You should as a minimum have a fuse in  primary and secondary of T1.... (added 4/05)

Better MOSFET H Bridge - (schematic / circuit added 6/07)

Bias supply accepts high inputs - 12/23/99 EDN-Design Ideas:.....(design idea added 3/03)

Boost Controller Drives Buck Converter - 02/03/97 EDN-Design Ideas: The usual way to step down a low voltage to a still lower one is to use a low-dropout (LDO)linear regulator. However, in battery-powered systems, the LDO usually doesn't deliver the maximum energy available. A cell count chosen for near-dropout operation when the battery is empty delivers too much voltage over most of the battery's discharge cycle, and a cell count chosen for maximum efficiency allows dropout well before the battery is empty. The highly efficient buck dc/dc converter in Figure 1 can solve the cell-count problem.....(design idea added 7/02)

Boost Converter Generates Three Analog Rails - 07/02/98 EDN-Design Ideas: The standard boost converter in Figure 1 uses not only IC1, C1, L 1, D1, and C2 to generate a main 5V output, but also additional small, low-cost components to provide two auxiliary
supply rails of 10 and –5V......(design idea added 6/06)

Bootstrapping Allows single rail OpAmp to provide 0V output - 02/06/03 EDN-Design Ideas: Many single-supply-powered applications require amplifier-output swings within 1 mV—or even submillivolts—of ground. Amplifier-output-saturation limitations normally preclude such operation. Figure 1's power-supply bootstrapping scheme achieves  desired characteristics with minimal parts count.....(design idea added 12/04)

Brush-Dc Servomotor Implementation using PIC17C756a - Microchip Application Note Published 12-Oct-99  (app note added 6/06)

Brushless DC Motor Control Made Easy - Microchip Application Note Published 12-Sep-02  (app note added 6/06)

Buck regulator & 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.....(design idea added 1/05)

Buck regulator forms high Power inverting –5V supply - 04/01/04 EDN-Design Ideas: Configuring a step-down switching-converter IC as an inverter yields an efficient, high-power, -5V supply that can of deliver currents as high as 4.5A at the 12V input or 3.2A at the 5V input (Figure 1). Conventional inverting power supplies do their switching using a p-channel MOSFET (Figure 2). That configuration works well at lower currents, but has limited use above approximately 2A, depend.....(design idea added 1/05)

Buck Regulator Generates Flexible VTT for PECL - 08/15/97 EDN-Design Ideas: -- Circuit to generate Output which can both Source and Sink Current -- The positive emitter-coupled logic (PECL)in most high-speed clock-distribution and -recovery circuits requires a termination voltage, VTT, that imposes special requirements on the VTT supply. First, the typical switching thresholds for PECL must refer to VDD instead of ground (VOL=VDD­1.32V+400 mV, and VOH=VDD­1.32­400 mV). The level of VTT, typically at VDD­2V, is slightly below VOL to ensure that the open-emitter outputs always source current (Figure 1a). Unlike most power-supply voltages, therefore, the supply must regulate VTT with respect to VDD instead of ground.....(design idea added 07/02)

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. A class of hysteretic switching regulators can actually operate at a relatively fixed frequency without a clock, even with changing input-line and output-loading conditions.....(design idea added 1/05)

Buck Regulator Terminates Fast Data Buses - 07/20/95 EDN-Design Ideas: (design idea added 3/03)

Buck Regulator uses Step Up Controller - 11/09/95 EDN-Design Ideas: (design idea added 3/03)

Build a Transformerless 12V to 180V DC/DC converter - 07/08/04 EDN-Design Ideas: Some transducers for portable or automotive applications need accurately regulated, high-voltage bias and draw little current. To produce such high voltages from a low battery voltage, designers typically use switch-mode dc/dc converters—generally, flyback converters. These converters exhibit high efficiency at medium or high output power.....(design idea added 1/05)

Calculating Power Dissipation & Supply Current in - Supertex Semiconductors  (app note added 2/06)

Calibration, compensation, & correlation - Coilcraft Power Magnetics Application Note (app note added 6/06)

Capacitor Charger Improves High Voltage Supply - 12/19/96 EDN-Design Ideas: (design idea added 3/03)

Capacitor improves efficiency in CPU supply - 04/04/02 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.....(design idea added 1/05)

CEMF counterelectromotive force charger - (circuit diagram added 05/06/07)

Charge Pump Efficiently Divides Supply Voltage  - This circuit uses a few FETs and logic devices to down convert a DC voltage to about one half its value ….(designed by David A. Johnson)

Charger for Gel Lead Acid Batteries - (Tony van Roon's electronic circuit added 4/05)

Chinese Translation: Design Guidelines for Off-line Flyback Converters using FPS/ AN-4137SC - Fairchild Application Notes / (app note added 6/06)

Circuit Design & Applications of the ADM663A/ADM666A Micropower Linear Voltage Regulators - AN-392 Analog Devices Application Note  (app note added 2/06)

Circuit Drives 9 Volt Solenoids from 3 Volt Battery - 08/17/95 EDN-Design Ideas: (design idea added 3/03)

Circuit Forms Simple Low Cost 1 Kv Driver - 05/13/04 EDN-Design Ideas: High-voltage drivers have recently received much attention, because they play an important role in driving piezoelectric and electro-optical components, for example. Figure 1 shows a simple, low-cost, 1-kV driver. The circuit uses offline, current-mode-control techniques and a flyback switching-power-supply design.....(design idea added 10/05)

Circuit Multiplexes Automotive Sensors - 01/20/00 EDN-Design Ideas:.....(design idea added 05/03)

Circuit Provides 15V 7Bus Termination - 09/14/95 EDN-Design Ideas: (design idea added 3/03)

Circuit provides leading edge Blanking - 05/29/03 EDN-Design Ideas: In isolated switch-mode power supplies using peak-current-mode control, generally the current-sense resistor senses the current on the primary side of the power converter. Figure 1 shows a typical circuit, in which R2 is the current-sense resistor that monitors the current. The current-sense signal goes to the input of the PWM comparator—in this case,.... (adden 02/05)

Circuit reduces negative voltage stresses on Control IC - 04/18/02 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. If the voltage goes too far below ground, the ESD structures or other circuitry within the control IC can become forward-bia.....(design idea added 1/05)

Circuit replaces & Improves on Power Modules at Less Than Half the Price - DN347  Design Notes (Linear Technology) (app note added 6/06)

Circuit Translates I 2C voltages - 12/26/02 EDN-Design Ideas: This Design Idea explores level-shifting an I˛C bus from 5V/ground (positive domain)to ground/25V (negative domain). In multisupply systems, you sometimes face a situation in which digital information stored in logic circuits running from 5V to ground needs conversion to analog signals referenced to a negative supply.... (adden 02/05)

Circuit Variations Produce Negative Voltages - 09/01/00 EDN-Design Ideas: / This circuits easily configures basic switched-capacitor converters to also do some negative conversions.  Basic switched-capacitor converters generally provide one simple conversion. They commonly double, usually invert, and sometimes halve a positive input voltage. Because they are not regulated converters and do.....(design idea added 11/05)

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 for this +5v supply but they will often discover that there just isn’t enough voltage from the transformer to make the circuit work properly under all but very light load conditions.  Higher transformer voltages will work but at the expense of much more power being dissipated in the voltage regulator.... ….(designed by David A. Johnson)

Clean Switcher Powers 16 Bit A/D Converters - 07/04/94 EDN-Design Ideas: The low-noise switcher in Fig 1 works much like a TV's horizontal-deflection circuit to provide clean power for a 16-bit A/D converter. In operation, Q3 is a logic-level gate-drive MOSFET driven by the same 100-kHz square wave that clocks the A/D converter. When Q3 turns off, the primary of T1 resonates with C3 and flies back to 25V. Energy.....(design idea added 3/03)

Coilless Step Up Converter yields Dual Outputs - 09/01/97 EDN-Design Ideas: (design idea added 3/03)

Common mode filter inductor analysis - Coilcraft Power Magnetics Application Note (app note added 6/06)

Comparator Adds Current Limit to V2 Controller - 05/21/98 EDN-Design Ideas: The subroutine "FASTBCD" (Listing 1)for 8051 µPs quickly converts 16-bit binary to 24-bit BCD data. The conversion algorithm involves left-shifting bits from the high-order bit of the binary number into the carry bit while left-shifting the carry bits into the low-order bit of a BCD shift register using BCD left-shift operations.....(design idea added 6/06)

Comparator Improves Regulator's Efficiency - 04/28/94 EDN-Design Ideas: The UC384X family of current-mode PWM regulators requires a current shunt or some other component to develop a voltage proportional to the output current. This shunt must develop a 1V signal at full load.  For off-line supplies, the 1V requirement is not hard to meet because of the high voltage on the supply's dc bus. However, if you want.....(design idea added 5/03)

Compressor-Mate - protection for refrigerators, freezers and air conditioners  (Tony van Roon's diagram added 05/06/07)

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,....(circuit added 7/02)

Constant Off-Time Buck-Based LED Drivers using HV9910 - Supertex Semiconductors (app note added 6/06)

Constant on time Buck boost regulator converts a positive input to a negative output - 12/07/04 EDN-Design Ideas: Buck regulators find wide application as step-down regulators for converting large positive input voltages into a smaller positive output voltages. Figure 1 shows a simplified buck regulator that operates in continuous-conduction mode—that is, the inductor current always remains positive. The output voltage, VOUT, is equal to D×VIN, where D is the duty-cycle ratio of the buck switc.....(design idea added 11/05)

Constant-Current DC/DC LED Driver in ThinSOT - Linear Technology LT1932 (app note added 2/05)

Converter Generates 33 Volt from Two or Three Cells - 11/11/96 EDN-Design Ideas: (design idea added 3/03)

Converter has High Efficiency at Low Loads - 01/06/94 EDN-Design Ideas: The high overhead of most dc/dc converters' normal supply currents do not permit high efficiency at low load currents. The micropower components and circuit design of the converter in Fig 1, however, enable it to maintain 90% efficiency for load currents below 8 mA.....(design idea added 3/03)

Cúk converter yiedls 90% efficiency - 09/01/94 EDN-Design Ideas: 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, IC2, 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. You can use this trick with any member of the 78LXX family.....(design idea added 2/05)

Current & temperature ratings - Coilcraft Power Magnetics Application Note (app note added 6/06)

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.....(design idea added 3/03)

Current Limiting Power Supply - This is a 1-amp variable-voltage PSU. It adjusts from about 3v to 24v: and has the added feature that you can limit the maximum output current. This is invaluable when (for example) you power-up a project for the first time or soak-test a piece of equipment. added 10/05)

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.....(design idea added 3/03)

Current-Limited DC/DC Converter Simplifies USB Power Supplies - DN252  Design Notes (Linear Technology) (app note added 6/06)