Transformerless Voltage Booster Circuit: A DC-DC Step-Up Switching Regulator Using Transistors

A DC-to-DC step-up converter is traditionally implemented using transformer, working by converting the DC voltage to AC Voltage, step-up it using transformer, then rectify and filter the transformer’s output to  get a higher DC voltage. Using a switching method, we can step-up a voltage without a transformer. We just need an inductor which is driven by a switching transistor to […]

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High Efficiency Switch Mode 3.3V 5A Step-Down Converter

This switch mode step-down converter has very good efficiency, up to 94% can be obtained. This switch mode regulator uses LTC1266-3.3 controller with external N-Channel power mosfet, and need only a 5uH inductor because it uses high frequency switching. Here is the schematic diagram of this switch mode step down converter circuit: To optimize efficiency, the LTC1266  automatically switches between […]

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Low-Drop-Out (LDO) Low-Voltage Linear Regulator Using NCP2860 IC

This low drop out (LDO) voltage regulator need only few components, with very low noise and very low drop-out voltage. The circuit illustrated in the schematic diagram below gives a fixed 2.77 volt output, but this output voltage can be adjusted using two additional resistors. This circuit capable to supply 300 mA load from 3.0 V to 6.0 V input.  […]

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Stand Alone 600mA Li-ion Battery Charger

A constant-current/constant-voltage linear charger for single-cell lithium-ion (li-ion) can be constructed using only a tiny battery charger controller chip EUP8054 and a few passive components. This tiny integrated circuit chip is suitable for various portable devices. This controller chip is also compatible with USB power specification, ideal for charging the battery when the device is plugged to USB port. Here […]

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Automatic 12V Lead-Acid Battery Charger

This charger circuit is suitable for lead-acid battery, including flooded, gel, and AGM types. The automatic term means that this charger will stop charging automatically when the battery voltage reach a certain pint, indicating that the battery has been fully charged, and charging will be restarted if the battery voltage falls below that threshold. A LED indicator is provided to […]

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