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60V/3A Step-Down DC/DC Converter

Published:2012/10/29 22:06:00 Author:muriel | Keyword: 60V/3A, Step-Down DC/DC Converter

60V/3A Step-Down DC/DC Converter
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4MHz Monolithic Synchronous Step-Down Regulators

Published:2012/10/29 22:06:00 Author:muriel | Keyword: 4MHz, Monolithic Synchronous , Step-Down Regulators

4MHz Monolithic Synchronous Step-Down Regulators
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3A, 2MHz Monolithic Synchronous Step-Down Regulator

Published:2012/10/29 22:05:00 Author:muriel | Keyword: 3A, 2MHz, Monolithic Synchronous, Step-Down Regulator

3A, 2MHz Monolithic Synchronous Step-Down Regulator
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10µA Quiescent Current Step-Down Regulators

Published:2012/10/29 22:04:00 Author:muriel | Keyword: 10µA , Quiescent Current , Step-Down Regulators

10µA Quiescent Current Step-Down Regulators
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LTC3453 - Synchronous Buck-Boost High Power White LED Driver

Published:2012/10/29 22:03:00 Author:muriel | Keyword: LTC3453 , Synchronous Buck-Boost, High Power, White LED Driver

LTC3453 - Synchronous Buck-Boost High Power White LED Driver
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Single Inductor, Tiny Buck-Boost Converter

Published:2012/10/29 22:03:00 Author:muriel | Keyword: Single Inductor, Tiny Buck-Boost Converter

Single Inductor, Tiny Buck-Boost Converter
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LM2673 Positive to Negative Converter

Published:2012/10/29 22:02:00 Author:muriel | Keyword: LM2673 , Positive to Negative Converter

LM2673 Positive to Negative Converter
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No Design Switiching Regulator

Published:2012/10/29 22:01:00 Author:muriel | Keyword: No Design Switiching Regulator

No Design Switiching Regulator
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Micropower Buck/Boost Circuits, Part 2

Published:2012/10/29 22:00:00 Author:muriel | Keyword: Micropower Buck/Boost Circuits

Micropower Buck/Boost Circuits, Part 2
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Micropower Buck/Boost Circuits

Published:2012/10/29 22:00:00 Author:muriel | Keyword: Micropower Buck/Boost Circuits

Micropower Buck/Boost Circuits
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Single-Cell Li-Ion Battery to 2.5V Converter

Published:2012/10/29 21:59:00 Author:muriel | Keyword: Single-Cell, Li-Ion Battery , 2.5V Converter

Single-Cell Li-Ion Battery to 2.5V Converter
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4-Switch Buck-Boost Converter

Published:2012/10/29 21:58:00 Author:muriel | Keyword: 4-Switch , Buck-Boost Converter

4-Switch Buck-Boost Converter
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Buck/Boost Charge-Pump Regulator Powers White LEDs from a Wide 1.6V to 5.5V Input

Published:2012/10/29 21:57:00 Author:muriel | Keyword: Buck/Boost, Charge-Pump Regulator, Powers White LEDs, Wide 1.6V to 5.5V Input

Buck/Boost Charge-Pump Regulator Powers White LEDs from a Wide 1.6V to 5.5V Input
Since their invention a few years ago, white light-emitting-diodes (LEDs) have been steadily gaining in popularity. Because they offer whiter light and longer life than incandescent bulbs and are easier to use than fluorescent tubes, they have been steadily gaining market share in a variety of lighting applications, such as flashlights and display backlighting in handheld electronics. However, white LEDs present their own set of technical issues.An obvious issue for battery-powered equipment is the high forward voltage of white LEDs, which is typically 3.6V at 20mA and is usually specified as 3.0V minimum to 4.0V maximum. Once the voltage-drop of ballast resistors is added, the required bias voltage is even higher; therefore, typical battery systems require a voltage boosting DC-to-DC converter. Recently, several IC manufacturers have introduced various charge-pump and inductor-based boost converter ICs dedicated to driving white LEDs; however, at the time of this writing, none of these ICs support low-voltage operation from a two-cell stack of NiMH or alkaline batteries. Also, some of these dedicated ICs fail to regulate properly or even shutdown properly when presented with a 5V input, such as from a wall adapter. Although never intended for white LED bias applications, the MAX1759 buck/boost charge-pump is the first charge-pump to regulate white LEDs from a wide 1.6V to 5.5V input range. As implemented in the circuit of Figure 1, the MAX1759 will bias the LEDs with 15mA from inputs including two NiMH cells, two alkaline cells, three NiMH cells, three alkaline cells, a single Li+ cell, a regulated I/O voltage of 2.5V or 3.3V, a 5V wall adapter, or any combination of these for flexible systems. Unlike most charge-pumps, the IC incorporates a buck mode for proper regulation with 5V inputs, and internal circuitry fully disconnects the output in shutdown, eliminating LED leakage current and associated battery drain when off. Other features include PWM dimming via the active-low SHDN pin and fold-back current limiting for short-circuit protection. (View)

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Buck Mode Switching Regulator for Solar Applications

Published:2012/10/29 21:56:00 Author:muriel | Keyword: Buck Mode, Switching Regulator , Solar Applications

Buck Mode Switching Regulator for Solar Applications
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Voltage follower with 1G ohm input resistance

Published:2012/10/29 21:54:00 Author:muriel | Keyword: Voltage follower, 1G ohm input resistance

This circuit uses an LM11 to form a voltage follower with 1G ohm input resistance built using standard resistor values. With the input disconnected, the input offset voltage is multiplied by the same factor as R2; but the added error is small because the offset voltage of the LM11 is so low. When the input is connected to a source less than 1G ohm, this error is reduced. For an ac-coupled input a second 10M resistor could be connected in series with the inverting input to virtually eliminate bias current error; bypassing it would give minimal noise. (View)