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Power Supplies:  DC to DC / Switch Mode and DC to DC Converters
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Last Updated: June 02, 2021 01:44 PM

Circuits Designed by Dave Johnson, P.E. :

Laptop Power Supply - Concept Only.  I have a big screen HP laptop computer.  The large brick size AC to DC power supply is rated at 19.2v and 9.5 amps, which is about 180 watts.  I’d like to be able to use the thing in my car.  I looked into a 12v car adapter for it but never really found one that I liked. . . . Hobby Circuit designed by Dave Johnson P.E.-July, 2009

 LC Oscillator Medium Power 125Khz - This circuit is similar to MEDIUM POWER 125KHZ OSCILLATOR but adds even more inverters in parallel to deliver yet more power.  The values shown are for 125KHz . . . Hobby Circuit designed by David A. Johnson P.E.-March, 2002


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

JFET cascode boosts current-source performance -  05/11/06 EDN Design Ideas:  A constant-current source minimizes the reference circuit's sensitivity to supply-voltage fluctuations and extends the voltage reference's operating voltage beyond its 5.5V maximum rating Design by Clayton B Grantham, Tucson, AZ

JFET-based DC/DC converter operates from 300-mV supply -  5/25/06  EDN-Design Ideas: You use a JFET’s self-biasing characteristics to build a DC/DC converter that operates from power sources such as solar cells, thermopiles, and single-stage fuel cells, all of which  deliver less than 600 mVYPDF has several circuits, you will need to scroll to find this one Design by Jim Williams, Linear Technology Corp, Milpitas, CA

L200 Power Supply -  Power supply with variable voltage and fixed current regulation made using the ubiquitous L200C regulator.   __ Designed by Andy Collison

LAB Power Supply -  This is a high quality power supply with a continuously variable stabilised output adjustable at any value between 0 and 30VDC.  The circuit also incorporates an electronic output current limiter that effectively controls the output current from a few milliamperes (2 mA) to the maximum output of three amperes that the circuit can deliver.  This feature makes this power supply indispensable in the experimenters laboratory as it is possible to limit the current to the typical maximum that a circuit under test may require, and power it up then, without any fear that it may be damaged if something goes wrong.  There is also a visual indication that the current limiter is in operation so that you can see at a glance that your circuit is exceeding or not its preset limits.  __ 

Laboratory Power Supply -  1.2V, 12V with regulated current limiter through resistors __ 

LAN Power Supply Generates Isolated 9V -  04/11/96 EDN Design Ideas:  A low-power, isolated 9V supply for LAN applications (Figure 1) delivers more than 250-mA load current.  For inputs of 10.8 to 13.2V and load currents of 1 to 200 mA, the nominal 8.78V output offers approximately ±1% line and load regulation.  iC1's transformer-driver outputs, D1 and D2, normally directly drive each end of a transformer primary.  Each driver terminal (on turn-off) sees a flyback voltage equal to twice the center-tap voltage.  The 24V flyback voltage in this application exceeds the 12V rating for iC1, so the circuit uses two MOSFETs in cascode to stand off the extra voltage and maintain the high switching frequency of IC 1 (typically 650 kHz). Design by Ron Young,  Maxim Integrated Products, Sunnyvale, CA

Laptop Power Supply -  Concept Only.  I have a big screen HP laptop computer.  The large brick size AC to DC power supply is rated at 19.2v and 9.5 amps, which is about 180 watts.  i’d like to be able to use the thing in my car.  I looked into a 12v car adapter for it but never really found one that I liked. . . . Hobby Circuit designed by Dave Johnson P.E.-July, 2009

LC Oscillator Medium Power 125Khz -  This circuit is similar to MEDiUM POWER 125KHZ OSCiLLATOR but adds even more inverters in parallel to deliver yet more power.  The values shown are for 125KHz . . . Hobby Circuit designed by David A. Johnson P.E.-March, 2002

LCD Bias & Backup Supply Applications for the LT1316 Micropower DC/DC Converter -  DN166 Design Notes__ Linear Technology/Analog Devices

Leakage-energy recuperating winding self-supplies a DC-DC converter -  EDN Design Ideas:  07/05/2013    Use a bifilar winding as a snubber to clamp ringing and power the PWM controller iC Design by Todor Arsenov

LIER Helps Power-Supply Efficiency -  02/16/95 EDN Design Ideas:  in high-frequency, high-power, low-input-voltage, flyback-converter power supplies, parasitic effects become overwhelmingly problematic.  The flyback inductor's required primary inductance, for example, can become so low that its accompanying leakage inductance becomes a significant fraction of the total inductance.  The energy stored in the primary leakage inductance lowers the circuit's efficiency and increases the power-rating requirements for the primary-winding switching device. Design by Brian Poindexter, Allied Signal Avionics Inc, Olathe, KS

Li-Ion boost uses no inductors -  09/12/1997 EDN-Design ideas To maintain a regulated 3.3V supply for portable applications, most Li-ion batteries require a low-dropout (LDO) regulator and a dc/dc boost circuit.  This need arises because the typical voltage range of a Li-ion battery is 4.2V (charged) to 2.5V (before recharge).  The regulator alone suffices in the battery range of 4.2 to 3.5V, but below that level, the battery voltage needs boosting to keep the LDO IC in regulation.  The circuit in Figure 1 senses the battery voltage via the R1-R2 resistor divider at comparator iC2.  The comparator turns off the converter when the battery voltage exceeds 3.6V.    Design by John Parry and Bill McIntyre,National Semiconductor, Grass Valley, CA

Li-Ion Powered Driver for 6 White LEDs & OLED Display -  The LT3466-1 integrates a high voltage boost converter for OLED Bias (16V AT 30mA) with a high performance white LED driver__ Linear Technology/Analog Devices App Note, Mar 24th 2010

Li-Ion Powered Driver for 6 White LEDs & OLED with Output Disconnect -  The addition of an external transistor adds output disconnect to the LT3466-1 boost converter__ Linear Technology/Analog Devices App Note, Mar 24th 2010

Li-Ion to 10 White LEDs & LCD Bias (+/-8V) with Output Disconnect -  With two small external switched capacitor networks, the LT3466-1 can provide both positive and negative bias voltages (+/- 8VAT10mA) for an LCD display as well as driving 10 white LEDs__ Linear Technology/Analog Devices App Note, Mar 24th 2010

Li-Ion to 8 White LEDs & +/-15V TFT LCD Bias Supply -  The LT3466-1 provides a small, integrated solution for TFT LCD Bias (+/-15VAT10mA) and backlighting (8 white LEDs) in a single package__ Linear Technology/Analog Devices App Note, Mar 24th 2010

Li-Ion to Six White LEDs & OLED/LCD Bias -  The LT3498 can provide both the positive bias voltage required for OLED or CCD bias as well as drive multiple white LEDs for display backlighting__ Linear Technology/Analog Devices App Note, Mar 24th 2010

Li-Ion to Two White LEDs & OLED/LCD Bias -  The LT3498 can provide both the positive bias voltage required for OLED or CCD bias as well as drive multiple white LEDs for display backlighting__ Linear Technology/Analog Devices App Note, Mar 24th 2010

Li'l PowerHouse Switchmode Power Supply -  This highly efficient design can deliver from 1.23V to 40V at currents up to 1.2A.__ SiliconChip

Li'l PowerHouse Switchmode Power Supply; Pt.2 -  Second article has all the construction details.  And we've improved the output filtering for even better performance.__ SiliconChip

Linear Regulator Converts 3.3 to 2.9V -  03/16/95 EDN Design Ideas:  A linear regulator is often a better choice for developing supply voltages below 3.3 V than a switching regulator.  At low output voltages and moderate currents, the linear regulator is less expensive and requires less pc-board are Design by Matt Schindler, Maxim Integrated Products, Sunnyvale, CA

LM2940 12V 1A Low Dropout Regulator -  Find out how to use an LM2940 to efficiently regulate voltage.   __ Designed by REUK-Renewable Energy UK website

LM2941 1A Low Dropout Adjustable Regulator -  Find out about the LM2941 - an adjustable regulator with very low dropout voltage.   __ Designed by REUK-Renewable Energy UK website

LM317 Current Calculator -  A handy online output current calculator for the LM317, LM338, and other linear voltage regulators.   __ Designed by REUK-Renewable Energy UK website

LM317 High Current Voltage Regulator -  Find out how to build an LM317T based high current voltage regulator.   __ Designed by REUK-Renewable Energy UK website

LM317 Regulator -  i constructed this voltage regulator to power my two way mobile radio from the car cigarette lighter circuit.  it has many other uses and the voltage can easily be adjusted by the use of a potentiometer.  The voltage regulator is an LM317T, and should accept up to about 14 volts without problems.  it can handle up to 1 amp, but you WiLL need a heatsink on the voltage regulator __ Designed by Matthew Hewson

LM317 Regulator with Pass Transistor -  The LM317T output current can be increased by using an additional power transistor to share a portion of the total current.  The amount of current sharing is established with a resistor placed in series with the 317 input and a resistor placed in series with the emitter of the pass transistor.  in the figure below, the pass transistor will start conducting when the LM317 current reaches about 1 amp, due to the voltage drop across the 0.7 ohm resistor __ Designed by Bill Bowden

LM317 Variable Voltage Regulator -  The LM317T is a adjustable 3 terminal positive voltage regulator capable of supplying in excess of 1.5 amps over an output range of 1.25 to 37 volts.  The device also has built in current limiting and thermal shutdown which makes it essentially blow-out proof __ Designed by Bill Bowden

LM317 Voltage Calculator -  A handy online output voltage calculator for the LM317, LM338, and other linear voltage regulators.   __ Designed by REUK-Renewable Energy UK website

LM317T Heatsinking -  Choosing a heatsink for use with an LM317T voltage regulator.   __ Designed by REUK-Renewable Energy UK website

LM317T Voltage Regulator Chip -  Learn about the LM317T and its uses in renewable energy projects.   __ Designed by REUK-Renewable Energy UK website

Logic PSU with OverVoltage Protection -  A simple 5 Volt regulated PSU featuring overvoltage protection. __ Designed by Andy Collison

Long Range FM Transmitter -  This circuit is a circuit diagram fm transmitter.  This circuit is somewhat different from the previous fm transmitter circuit.  Transmitter circuit described here has the additional RF power amplifier stage, after the oscillator stage, to increase the power output of 200-250 milliwatts.  With a good matching 50-ohm ground plane antenna or multi-element yagi antenna, this transmitter can provide a good enough signal strength to a distance of about 2 kilometers.__ 

Long Range FM Transmitter -  The power output of many transmitter circuits are very low because no power amplifier stages are incorporated.  The transmitter circuit described here has an extra RF power amplifier stage, after the oscillator stage, to raise the power output to 200-250 milliwatts.  With a good matching 50-ohm ground plane antenna or multi-element Yagi antenna, this transmitter can provide reasonably good signal strength up to a distance of about 2 kilometres.  The circuit built around transistor T1 (BF494) is a basic low-power variable-frequency VHF oscillator.  A varicap diode circuit is included to change the frequency of the transmitter and to provide frequency modulation by audio signals.  The output of the oscillator is about 50 milliwatts.  Transistor T2 (2N3866) forms a VHF-class A power amplifier.  it boosts the oscillator signal power four to five times.  Thus, 200-250 milliwatts of power is generated at the collector of transistor T2.__ 

Long Range FM Transmitter -  The power output of many transmitter circuits are very low because no power amplifier stages are incorporated.  The transmitter circuit described here has an extra RF power amplifier stage, after the oscillator stage, to raise the power output to 200-250 milliwatts.  With a good matching 50-ohm ground plane antenna or multi-element Yagi antenna, this transmitter can provide reasonably good signal strength up to a distance of about 2 kilometres __ Designed by Submitted Viswanathan Prakash 29-1-10

Low Cost High Efficiency 30A Low Profile PolyPhase Converter -  DN211 Design Notes__ Linear Technology/Analog Devices

Low Cost High Efficiency 42A DC/DC Converter -  DN225 Design Notes__ Linear Technology/Analog Devices

Low Cost PolyPhase™ DC/DC Converter Delivers High Current -  DN234 Design Notes__ Linear Technology/Analog Devices

Low Cost Surface Mount DC/DC Converter Delivers 100A -  DN215 Design Notes__ Linear Technology/Analog Devices

Low Dropout 550kHz DC/DC Controller Operates from Inputs as Low as 2V -  DN208 Design Notes__ Linear Technology/Analog Devices

Low EMI Synchronous DC/DC Step-Down Controllers offer Programmable Output Tracking -  DN382 Design Notes__ Linear Technology/Analog Devices

Low Noise ±12V Power Supply from a Single-Ended 15V Input Supply -  The LTC3260 is a low noise dual polarity output power supply that includes an inverting charge pump with both positive and negative LDO regulators.  The charge pump operates over a wide 4.5V to 32V input range and can deliver up to 100mA of output current.  Each LDO regulator can provide up to 50mA of output current.  The negative __ Linear Technology/Analog Devices App Note, Apr 19th 2012

Low Noise Micropower DC/DC Converters LT1500/LT1501 -  DN151 Design Notes__ Linear Technology/Analog Devices

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