AC-DC & DC-DC Circuits
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Ul, an LM317 adjustable regulator provides short-circuit protection and automatic current limiting at 1.5 A. The input voltage to the regulator is supplied by DBl, a 4-A 100 PIV full-wave bridge rectifier. Capacitor Cl provides initial filtering. Ul....
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The circuit powers the load via the regulator"s input instead of its output. Because the regulator"s output sees constant dummy load R1, it tries to consume a constant amount of current, no matter what the voltage across the actual load really is. Hence,....
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The variable voltage regulator lets you adjust the output voltage of a fixed de power supply between 1.2 and 37 V de, and will supply the output current in excess of 1.5 A. The circuit incorporates an LM117K three-terminal adjustable output positive....
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This circuit uses two comparator pairs from an LM339N quad comparator; one pair drives the yellow positive (+)and negative (-)indicators, the other jointly drives the red warn LED3. The circuit draws its power from the unregulated portion of the power....
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This circuit shows a typical over/under-voltage fault monitor for a single supply. The upper trip points, controlling OUT 1, are centered on 5.5 V with 100 mY of hysteresis Wu = 5.55 V, "L = 5.45 V); and the lower trip points, controlling OUT 2, are....
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This circuit provides accurate full-wave rectification. The output impedance is low for both input polarities, and the errors are small at all signal levels. Note that the output will not sink heavy currents, except a small amount through the 10-K!J....
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817V The outputs in this circuit are independently variable and can be loaded unsymmetrically. The output voltage remains constant, irrespective of load and changes. By varying potentiometers R2 or R6, the output voltages can be conveniently set.....
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In this application, the Vl-7660 is connected as a voltage splitter. Note that the normal output pin is connected to ground and the normal ground pin is used as the output. The switches that allow the charge pumping are bidirectional; therefore, charge....
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Ul is a dual voltage comparator with open collector outputs. The A side is an oscillator operating at 100kHz, and the B side is part of the regulation circuit that compares a fraction of the output voltage to a reference generated by zener diode D2. The....
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This converter delivers up to 50 mA from a 6-V battery with 78% efficiency. This flyback converter functions by feedback-controlling the frequency of inductive flyback events. The inductor"s output, rectified and filtered to de, biases the feedback loop to....
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This nonisolated, unregulated, minimum component converter fills the void between low-power zener regulation and the higher power use of a 60-Hz input transformer. It is intended for use where)"er a nonisolated supply can be used safely. The circuit....
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The buck-boost configurationnf the MAX634 is well suited for dual output de-de converters. Only a second winding on the inductor is needed. Typically, this second winding is bifilar-primary and secondary are wound simultaneously using two wires in....
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Many devices operate from a car"s 12-V electrical system. Some require 12 V; others require some lesser voltage. An automobile battery"s output can vary from 12 to 13.8 V under normal circumstances. The load requirements of the device might vary. This....
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Regulation is provided by taking the rectified output of the sense winding and applying it as a bias to the base of Q2 via zener Dl. The collector of Q2 then removes drive from the gate of Ql. Therefore, if the . output voltage should increase, Q2 removes....
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For systems with only one power supply, two op amps act as instrumentation and buffer amps. The OPA111..
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This bridge will measure inductances from about 1 to 30 at a test frequency of 5 mHz. A 365-pF AM-type tuning capacitor ..
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This circuit was used to produce a variable negative voltage for contrast control of an LCD displa..
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A common power-supply requirement involves converting a 2.4- or 3-V battery voltage to a 5-V logic suppl..
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Used on an amateur or experimental radio beacon, the above ID circuit will generate any callsign or message program..
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The noninvertiiig terminal of the op amp is grounded, and the circuit uses the voltage at the inverting t..
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This circuit provides a unique solution to a common system-level power distribution problem: When the su..
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IC1 is a switching regulator that generates a 45-kHz signal that drives the gate of MOSFET Ql. Dl, D2, an..
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Laptop computers often use large-screen LCDs, which require a variable and a negative supply to ensure maxi..
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Optically isolated SMPS and dc-to-dc converters face the variance of output voltage owing to the change of transmission c..
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Many power-factor-correction circuits use a boost converter to generate a regulated dc output voltage from the ac line inp..
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By coupling two back-to-back diodes in series with an ac power circuit, a voltage of about 1.4 Vpp can be obtained. This..
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The dc-dc converter substitutes a voltage tripler in place of the external inductor and the diode that"s typically as..
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Most small portable radios require a 3-V supply, which is normally provided by two AA or AAA batteries..
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This bridge circuit is intended for those cases where two unequal supply voltages are required. The lower voltage is obtai..
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A current source that attains a resolution as low as 10 pA is useful in applications where a precise, low-value ..
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This circuit provides a precision voltage source that can be adjusted through zero to positive a..
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A fixed current flows through any load that is connected between the positive supply and Ql"s collector. The noninverting..