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Power Supply Circuits
Battery Charger Circuits
Battery Charger Circuits
AA Battery Solar Charger
This almost trivial circuit may be used to charge a pair of AA or AAA sized rechargeable battery cells from sunlight. The circuit has been used to keep a Palm Pilot and walkman radio running perpetually. This is an unregulated charger, proper charging is achieved by placing the unit in the sun for a known amount of time, this time varies...
Switching regulator charges NiMH batteries
In Figure 1, an MC34063A switching regulator and an MC33342 NiMH battery-charger IC combine to generate from an unregulated power supply a 600-mA battery charger for one to four NiMH cells.
Microcontroller controls battery charger
Figure 1 is a generalized block diagram of a multichemistry battery charger. A COP8ACC5 µC handles its key charging features. The µC is available in a 20-pin (15 I/O pins) SOIC or a 28-pin (23 I/O pins) SOIC/DIP. It contains 4 kbits of internal ROM.
Li-ion battery charger
The circuit in Figure 1 can solve this problem by providing a constant 300-mV drop between VIN and VOUT at currents as high as 3A. The accuracy of the 300-mV drop is nearly as good as the accuracy of the input voltage, which in this case is approximately 1%. This circuit requires an input voltage that is fixed, regulated, and preferably...
12 VOLT GEL CELL CHARGER
When a discharged gel cell is connected, the charger goes into a fast charge mode at a fixed rate of 400 ma. After the chip detects the voltage leveling off or when 4 1/2 hours has elapsed. (which ever happens first.) the fast charge will stop. After the fast charge has ended, the IC goes into a trickle charge rate of about 50 ma. This trickle...
Charge indicator gauges lead-acid batteries
A simple circuit measures the open-circuit voltage, such as the expanded-scale voltmeter circuit in Figure 2, which follows the curve in Figure 1. Sealed lead-acid batteries are available in several sizes, from a single D size (2.5 Ahr) to multicell rectangular battery packs.
Car Battery Charger
This charger will quickly and easily charge most any lead acid battery. The charger delivers full current until the current drawn by the battery falls to 150 mA. At this time, a lower voltage is applied to finish off and keep from over charging. When the battery is fully charged, the circuit switches off and lights a LED, telling you that the...
This circuit was specifically designed to recharge alkaline cells. The unusual connection of the transistor in each charging unit will cause it to oscillate, on and off, thus transferring the charge accumulated in the capacitor to the cell. The orange LED will blink for around 5 times a second for a 1.37V cell. For a totally discharged cell the...
Sealed Lead-Acid Charger
Here`s how to make a good charger for a sealed lead-acid battery (this will NOT work with NiCad batteries) that`s faster (because it allows more current into the battery initially) and safer (because it uses lower voltage when the charging is finished). The battery can be left plugged into this charger indefinitely, and it won`t bother it in the...
Temperature Controlled NICD Charger
This circuit is for a temperature controlled constant current battery charger. It works with NICD, NIMH, and other rechargeable cells. The circuit works on the principle that most rechargeable batteries show an increase in temperature when the cells becomes fully charged. Overcharging is one of the main causes of short cell life, hot cells pop...
Nicad Battery Charger
This simple charger uses a single transistor as a constant current source. The voltage across the pair of 1N4148 diodes biases the base of the BD140 medium power transistor. The base- emitter voltage of the transistor and the forward voltage drop across the diodes are relatively stable. The charging current is approximately 15mA or 45mA with...
This application note presents practical design considerations for battery chargers employing Green Mode FPS (Fairchild Power Switch). It includes designing the transformer and output filter, selecting the components and implementing constant current / constant voltage control.
Dual Smart Battery Charger
Figure 1 shows a typical dual battery charger. This circuit can charge batteries with up to 4A and switch continuously down to zero load currents. This circuit takes advantage of ceramic capacitors space saving features without producing any audible noise. The high 300kHz switching frequency allows the use of small low cost 10µH inductors.
CHARGER WITH ANALYSER
Nowadays maintenance-free lead-acid batteries are common in vehicles, inverters, and UPS systems. If the battery is left in a poor state of charge, its useful life is shortened. It also reduces the capacity and rechargeability of the battery. For older types of batteries, a hygrometer can be used to check the specific gravity of the...
MOBILE CELLPHONE CHARGER
Charging of the cellphone battery is a big problem while travelling as power supply source is not generally accessible. If you keep your cellphone switched on continuously, its battery will go flat within five to six hours, making the cellphone useless. A fully charged battery becomes necessary especially when your distance from the...
MOBILE PHONE BATTERY CHARGER
Mobile phone chargers available in the market are quite expensive. The circuit presented here comes as a low-cost alternative to charge mobile telephones/battery packs with a rating of 7.2 volts, such as Nokia 6110/6150.
Li-Ion Charge Termination IC
Rechargeable lithium-ion batteries are rapidly becoming the battery of choice for many battery-powered products. These products include notebook computers, PDAs, video camcorders, digital cameras, cellular phones, portable test equipment and others. Compared to other rechargeable power sources, Li-Ion batteries have higher energy density...
Li-Ion Charge Termination Using the LT1505
Li-Ion batteries are normally charged with a current limited constant voltage for a fixed length of time. At the end of this time period, the voltage must be removed to prevent internal chemistry changes in the battery. At a minimum, a timer is needed to terminate the charging process after the maximum amount of time required to fully...
Li-Ion Linear Charger
Linear battery chargers are typically smaller, simpler and less expensive than their switcher-based counter parts, but they have one major disadvantage: excessive power dissipation when the input voltage is high and the battery voltage is low (discharged battery).
High Efficiency Lithium-Ion Battery Charger
The LT®1510 current mode PWM battery charger is the simplest, most efficient solution for fast charging modern rechargeable batteries including lithium-ion (Li-Ion), nickelmetal- hydride (NiMH) and nickel-cadmium (NiCd) that require constant current and/or constant voltage charging. The internal switch is capable of delivering 1.5A DC...
4-Cell Ni-Cad Regulator/Charger
The new LTC1155 Dual Power MOSFET Driver delivers 12V of gate drive to two N-channel power MOSFETs when powered from a 5V supply with no external components required. This ability, coupled with its micropower current demands and protection features, makes it an excellent choice for high side switching applications which previously required...
Circuit Charges Lithium-Ion Cells
The charger is built around a single LTC®1541, which contains a voltage reference, op amp and comparator. The high accuracy voltage reference (±0.4%) regulates the battery float voltage to ±1.2%, as required by most Lithium-Ion battery manufacturers.
New Charger Maximizes Charging Speed
The block diagram in Figure 1 shows the basic functions performed by a battery charger IC using this patented topology*. The LT1511 is a high efficiency 200kHz switching regulator IC in a step-down configuration suitable for charging lithium-ion batteries. It contains multiple feedback loops for constant charge voltage, constant charge...
Smart Battery Charger
Typically such applications require low power from the battery. With this in mind, every feature of the LTC4100 Smart Battery charger exists to reduce board real estate and profile requirements. The LTC4100 is a Level 2 (slave) Smart Battery charger that is compliant with both Smart Battery Charger V1.1 and SMBus V1.1 standards.
Standalone NiMH/NiCd Battery Charger
The LTC®4010 and LTC4011 are NiCd/NiMH battery chargers that simplify Nickel-based battery charger design and include power control and charge termination for fast charging up to 16 series-connected cells using a synchronous buck topology. The LTC4011 provides a full feature set in a 20-lead TSSOP while the LTC4010 comes in a 16-lead TSSOP.
Charge Monitor for 12V Lead-acid Battery
The circuit possesses two vital features: First, it reduces the requirement of human attention by about 85 per cent. Second, it is a highly accurate and sophisticated method. Input from the battery under test is applied to LM3914 IC. This applied voltage is ranked anywhere between 0 and 10, depending upon its magnitude.
Battery Charger & DC/DC Converter
The LTC1980 manages both battery charging and generaton of the regulated system bus voltage via a unique bidirectional pulse-width modulator design (Figure 3). When the wall adapter is present, power passes directly to the system load DC/DC converters and to a pulse widthmodulated battery charger formed by M1, M2, T1 and the LTC1980.
Charge current: I=0,45V/R2 Power-dissipation by R2: (0,45 * 0,45 / R2) ! Please adjust 13,8V by R5 without connected battery.
Simple Lead Acid Battery Charger
The above pictured schematic diagram is just a standard constant current model with a added current limiter, consisting of Q1, R1, and R4. The moment too much current is flowing biases Q1 and drops the output voltage. The output voltage is: 1.2 x (P1+R2+R3)/R3 volt. Current limiting kicks in when the current is about 0.6/R1 amp. For a 6-volt...
Simple Li-Ion Battery Charger
Charging current is about 100+mA, which is the internally-limited maximum current of the LP2951. For those wondering, this is compatible with just about any single-cell li-ion battery since li-ion can generally accept a charging current of up to about 1c (i.e. charging current in mA equivalent to their capacity in mAh, so a 1100mAh li-ion cell...
Mobile Phone Charger with CA3130
The circuit described here provides around 180mA current at 5.6V and protects the mobile phone from unexpected voltage fluctuations that develop on the mains line. So the charger can be left ?on? over night to replenish the battery charge. The circuit protects the mobile phone as well as the charger by immediately disconnecting the output when...
Lead Acid Battery Charger with LED indicator
The above circuit is a precision voltage source, and contains a temperature sensor with a negative temperature co?ficient. Meaning, whenever the surrounding or battery temperature increases the voltage will automatically decrease. Temperature co?ficient for this circuit is -8mV per °Celcius. A normal transistor (Q1) is used as a temperature...
Free Energy Circuits
AC-DC & DC-DC Circuits
Solar Cell Circuits
Current Limiting Circuits
Micro Power Circuits
High Voltage Circuits
Switching Power Supply Circuits
Ultrasonic distance finder circuit
The circuit described here uses ultrasonic oscillations and operates based on the propagation velocity of these oscillations in the air. Thus, we can easily determine the distance of two points if the time within which the wave travels this distance is measured. There are three main categories of distance measurement methods in use: a) By...
Simple Metal detector circuit with CD4030
Sometimes the precious metals are hidden too deep and are not detected except with complicated devices. In many cases, however, small pieces of precious metal buried near the surface can be detected by relatively simple means. Everyone is very attractive to find something potentially valuable, hidden a few centimeters below the soil. So many...
Fully automatic watering circuit for flower pots
Many times for various reasons we forget or can not water the plants that we have in our homes. And many humidity sensors units just notify us with a beeping sound or with a flashing light, that the pot needs watering. But what if we are away from home? This circuit comes as a solution to this problem. Depending on humidity of the pot at...
Simple deep searching metal detector circuit
The principle behind a metal detector is really very simple. Proof of this is the circuit that follows, in which it proves that the construction of a metal detector can be done in the minute, with few components that we find very easily everywhere. With the circuit of this metal detector, it is possible to detect a metal coin in depth of 90 to...
Sub-Harmonic Bass Converter for Electric Guitars
The sub-harmonic bass generator is a sound producing unit for guitars. The sound it produces looks very much like that of the bass guitar. The octave generator is sometimes quite unusual since it does not produce any of the usual ways of coloring the sound, such as filtering or distortion. Instead, a frequency division system produces outputs...
Echo Depth Sounding Sonar for Boats
In the past the sounding (sea bottom measurement) was done with the "bullet", that is, with a heavy lead object that the seamen plucked into the sea hung from a calibrated rope. As soon as the "bullet" reached the bottom, the depth appeared directly from the calibration of the rope. This arrangement still exists in some yachts. The big...
100W HiFi Audio Amplifier Circuit
This Amplifier was designed to have the following specifications: Distortion less than 0.1% at full power of 100W even at 20KHz. Power has to be attributed to an extended bandwidth. The output transistors must be protected against short circuits. The power supply must be symmetrical so that no electrolytic capacitors are needed at the outlet....
Plant-Pot Water Level Indicator Circuit
A series of LEDs serve to alert the gardener when plants need water. Using two conventional digital integrated LEDs and a series of LEDs, we make a very useful device for gardening. The device detects the amount of water in the pot and alerts the grower. The circuit of the device is shown in Figure 2. The water detection is made from the bottom...
Analogue Sound Preasure dB-Meter Circuit
The best human ear can capture sounds from 20Hz to 20KHz. These limits are known to be the broadest that can exist. Normally the normal limits range from 100Hz to about 13KHz and depend on the age and health of the individual. We for our measurements and to have a good accuracy we will get the limits of 20Hz to 20KHz. A sound to be heard does...
DIY HV Variable Capacitor
DIY PMA Alternator Plans
Digital Signal Integrity