Battery Booster Delivers 75W:  07/16/98 EDN Design Ideas / (added 07/02) The circuit in Figure 1 defies no laws of physics; it just makes creative use of an isolated dc/dc converter. The application uses the isolated converter in a nonisolated configuration to boost a 48V battery voltage to 60V. The PT3102 is a 15W isolated dc/dc converter that normally uses a 36 to 75V (48V-nominal) input voltage to provide a floating, or isolated, 12V output capable of 1.25A. The trick is to connect the negative-output lead and positive-input lead of the converter, thereby effectively stacking the 12V output on top of the 48V input. (Be aware that the original isolation and safety properties of the converter no longer exist in this configuration.)....

Bipolar Transistor Boosts Switcher's Current by 12 times:  05/24/01 EDN-Design Ideas / (added 8/03)

Boost 33V to 5V with Tiny Audio Amplifier:  09/05/02 EDN Design Ideas  /  (added 12/04)  This charge-pump circuit quietly converts a 3.3V source to 5V at 500 mA (figures 1 and 2). National's (www.national.com) LM4871LD power amplifier makes this design idea both possible and practical, thanks to its low output resistance, low cost, compact size, and high dissipation capability. Its output resistance has an average value of 0....

Boost Controller Drives Buck Converter:  02/03/97 EDN Design Ideas / (added 3/05)   -- 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 Controls 12 Volt Fan from 5 Volt Supply:  12/12/97 EDN-Design Ideas / (added 3/03)   --Temperature-controlled PWM boost converter allows operation of a12V brushless dc fan from a5V supply

Boost Converter Generates ­27 and ­87V:  05/22/97 EDN-Design Ideas / (added 3/03)   -- Generates the voltage levels necessary for standard telephones from12V

Boost Converter Generates Three Analog Rails #2:  07/02/98 EDN-Design Ideas / (added 3/03)  The standard boost converter in Figure 1 uses not only IC1, C1, L1, 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. These auxiliary outputs are useful for analog circuitry in small handheld instruments, which often require supply voltages greater than the signal range. Input voltages of 0.8 to 5.5V, which is equivalent to voltages from a battery pack of one to three cells, sustain the main regulated output of 5V±2%. With an input of 1.8V from two flat cells, for instance, and with the other rails unloaded, the circuit can produce 25 mA with 80 to 90% efficiency.

Boost Converter Generates Three Analog Rails:  Maxim Application Note #2026 (app note added 7/03) In Figure 1, a standard boost converter consisting of IC1, C1, L1, D1, and C2 generates, in addition to the main output, two auxiliary supply rails (10V and -5V) with the addition of some small and very low-cost extra components. Such rails are useful for the analog circuitry in small handheld instruments, which often require supply voltages in excess of the signal range....

Boost Converter Works with Wide Range Negative Input Supply:  03/18/04 EDN Design Ideas  /  (added 1/05)  Assume that a design requires positive voltage, but only a negative-voltage power source is available. Using a standard boost-converter IC in the circuit of Figure 1, you can efficiently generate a positive voltage from a negative source. The boost converter generates an output voltage that's higher than the input voltage....

Boost Reference Design:  This design uses the UCC38C43 as a boost power supply controller. It operates from a 12 volt input and generates a 24 volts (or higher) output voltage. The input voltage can be widely varying as the UCC38C43 can sustain a 20 volt maximum input. (added 3/05)

Boost Regulator Makes Low Profile SEPIC with Both Step-Up and Step-Down Capability:  DN317 -  Design Notes (Linear Technology) (app note added 2/06)

Boosting Regulator Current:  Although the 78xx series of voltage regulators are available with different current outputs, you can boost the available current output with this circuit. A power transistor is used to supply extra current to the load the regulator, maintaining a constant voltage.  Currents up to 650mA will flow through the regulator, above this value and the power transistor will start to conduct, supplying the extra current to the load. This should be on an adequate heat sink as it is likely to get rather hot. Suppose you use a 12v regulator, 7812. The input voltage should be a few volts higher to allow for voltage drops. Assume 20 volts. Lets also assume that the load will draw 5amps. The power dissipation in the transistor will be Vce * Ic or  (20-12)*8=40watt. It may keep you warm in the Winter, but you will need a large heatsink with good thermal dissipation. If you want to increase the output current with a negative regulator, such as the 79xx series, then the circuit is similar, but an NPN type power transistor is used instead.      (added 7/06)

Bootstrapped Boost Converter operates at 1.8 Volt :  04/23/98 EDN-Design Ideas  /  (added 05/03)

Bootstrapped Timer:  This circuit demonstrates how to use bootstrapping to seriously boost the output power of the timer. The LC555 can only put out about 50mA as it is. This circuit can put out at least 200mA and goes to the rail as well. The LM555 timer puts out 300mA max, but doesn’t go all the way to the rail. Replace Q1 with a big MOSFET, and you can put out big current with these few components.  Designed by Andrew R. Morris  (added 09/05)

Buck Converter Handles Battery Backup System:  04/24/03 EDN Design Ideas  /  (added 12/04)  A synchronous buck converter is inherently bidirectional. That is, it transfers energy from input to output as a buck regulator when the output voltage is low, but, when the output voltage is high, the converter acts as a boost regulator, transferring power from output to input. This Design Idea shows how to use this bidirectional energy transfer to automatically recharge a battery when the mai......

Buck IC Boosts Battery Voltage for White LED:  04/24/03 EDN Design Ideas  /  (added 1/05)  White-light LEDs are finding their way into many markets that incandescent bulbs once served. Flashlights are among the newer applications in which reliability, ruggedness, and ability to control the power draw of the LEDs make these devices attractive. With incandescent bulbs, the power management for the device is a simple on-off switch....

Buck or Boost: Rugged Fast 60V Synchronous Controller Does Both:  DN370 -  Design Notes (Linear Technology)  (app note added 1/06)

Build a Charge Pump with UltraLow Quiescent Current:  09/05/04 EDN Design Ideas /  (added 1/05)  Portable battery-powered devices often spend most of their life in standby mode, in which the quiescent current of an internal boost converter continuously bleeds the battery. The quiescent current during standby can be larger than the actual load current. Though several inductor-based converters offer maximum quiescent current of less than 10 µA, designers usually prefer or require a regu......