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Battery Backup Regulator is Glitch-Free and Low Dropout: DN170 -
Design Notes (Linear Technology) (added 2/06) |
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Bench Top Power Supply Auto-Fan: (Circuit added 9/04) |
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Bench Top Power Supply Part 1: (Circuit added 9/04) |
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Bench Top Power Supply Part 2: (Circuit added 9/04) |
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Bench Top Power Supply Part 3: (Circuit added 9/04) |
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Bench Top Power Supply Part 4: (Circuit added 9/04) |
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Big Power for Big Processors: The LTC1430 Synchronous Regulator: DN113 -
Design Notes (Linear Technology) (added 1/06) |
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Bleeper Box for time reference: (circuit / schematic added 6/05) |
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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. (circuit design added 3/05) |
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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 10/05) |
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Bootstrapped boost converter operates at 18V : 04/23/98 EDN-Design Ideas
/ (added 11/05) [Note: File contains multiple circuits - scroll to find this circuit.] Many circuits, such as those that use
batteries or solar cells, must operate in the face of decreasing supply voltages. The circuit in Figure 1 maintains the maximum load current
as the supply voltage drops. The regulator boosts a 2.5 to 4.2V input to 5V and provides 2A load current, for 10W of output power. The circuit
is a bootstrapped synchronous boost regulator that uses an LTC1266 synchronous-regulator controller. Diodes D1 through D5 allow the circuit to
start up using the low input voltage and then to receive its power from the higher output voltage during normal operation. The crucial
elements in the circuit are the switches: two IRF7401 n-channel MOSFETs. The MOSFETs receive full enhancement at low gate-source voltages. (At
VGS=2V, the peak drain current is 15A.) The low enhancement voltages allow the circuit to start with low input voltages.... |
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Capacitance Multiplier Power Supply for Class a Amplifiers:
(Electronic Schematic / circuit added 4/02) |
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Car Battery Charger: quickly and easily charge most any
lead acid battery, automatically turns charging off when ready (Electronic circuit added 5/02) |
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Car Converter for 12 Volt to 9V: (added 3/’03) |
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Car NiCd Charger: This circuit provides up to20-Volt
output from a regular13.2V automotive battery, to enable constant current charging of NiCd battery packs up to15 cells @1.2V (18V total).
(Electronic circuit added 5/02) |
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Ceramic output capacitors enhance internally
compensated switchers: 7/20/06 EDN - Design Ideas / (added 10/06) Restore switching regulator stability when
you change output-capacitor compositions. |
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Change Improves Regulators’ Reliability: 05/12/94
EDN-Design Ideas / (Electronic Circuit diagram added 03/03) The standard circuit for adjustable, 3-terminal regulators (LM317, LM350, etc) in
Fig 1a suffers from a designed-in fault: If the potentiometer R2’s wiper loses contact, the regulator’s output goes high. Because the
potentiometer is the most unreliable part in the circuit, consider using the circuit in Fig 1b. Now, if the potentiometer’s wiper loses
contact, the circuit’s output goes low, and R3 limits the output-voltage excursion even if the potentiometer shorts out. (DI #1416) Fig
1—A simple change in the topology of a 3-terminal regulator’s circuit.... |
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Circuit improves on Bias for GaAs FETs: 12/06/01 EDN
Design Ideas / (added 1/05) It's important to properly sequence the bias applied to an RF/microwave GaAs FET or a MMIC
(monolithic-microwave-IC) amplifier. These devices are extremely sensitive to drain and gate voltage levels as well as to the order in which
these biases turn on and off. A GaAs-FET amplifier that uses two bias voltages-a negative supply, VGG, on its gate and a positive supply, VDD,
on its dra... ... |
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Circuit provides ADSL frequency reference: 05/25/00
EDN-Design Ideas / (added 2/06) |
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Circuit provides leading edge Blanking: 05/29/03 EDN
Design Ideas (adden 02/05) In isolated switch-mode power supplies using peak-current-mode control, generally the current-sense resistor
senses the current on the primary side of the power converter. Figure 1 shows a typical circuit, in which R2 is the current-sense resistor
that monitors the current. The current-sense signal goes to the input of the PWM comparator—in this case, the PWM comparator's input
(ISENS...... |
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Circuit provides reference for multiple ADCs: 01/24/02
EDN Design Ideas / (added 1/05) The achievable accuracy for systems with multiple ADCs depends directly on the reference
voltages applied to the ADCs. Medical-ultrasound-imaging systems, for example, commonly include a large number of ADCs in the system's
beam-former electronics, with the ADCs usually organized in groups of 16, 24, 32, and so on. ... |
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Compact Step-Up Converter Conserves Battery Power: DN358 - Design
Notes (Linear Technology) (app note added 2/06) |
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Constant Current Battery Charger: (circuit added 7/02) |
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Create a Virtual Ground with the LT1118-2.5 Sink/Source Voltage Regulator:
DN115 - Design Notes (Linear Technology) (app note added 2/06) |
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Current sensing scheme improves PFC on/off sequences:
06/27/02 EDN Design Ideas / (added 1/05) PFC (power-factor-correction) preconverters typically use the step-up, or boost,
configuration, because this type of converter is relatively easy to implement (Figure 1). However, this topology requires the output voltage
to be higher than the input voltage. When this condition is not the case—for example, with on/off sequences or under load conditions—some
inrush current flows thro...... |
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