Switching Power Supply Using the LMZ14202H

Using the LMZ14202H power switching controller, can be designed a very simple switching power supply circuit that can provide a fixed output voltage covering a wide range of voltages .

Switching Power Supply Circuit diagram

This power switching power supply electronic project will provide a fixed output voltage between 5 and 30 volt from an input voltage between 8 and 42 volt at a maximum output current of 2 ampere . This circuit project power supply require few external electronic parts and can be configured very easy . In the table bellow you can see components value that are required for different output voltage

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230 V AC To 400 V DC Power Supply Circuit Diagram

Description

               A lot of students are who dont know how to convert 230 volt AC to 400 DC. So today I am published   230 V AC to 400 V DC circuit diagram on my blog. Working principle of this circuit diagram is very simple. You already knew the working principle of a bridge rectifier. This circuit is same as bridge rectifier and the working principle is also same. The fuse is used to protect the circuit, if the current is greater than 1 A.


Parts List

Component No:	Value
F1	1 A
B1	IN4007
C1	470MF/450V
V1	230 V AC

Source by : link

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Mains Supply Failure Alarm

Whenever AC mains supply fails, this circuit alerts you by sounding an alarm. It also provides a backup light to help you find your way to the torch or the generator key in the dark. The circuit is powered directly by a 9V PP3/6F22 compact battery. Pressing of switch S1 provides the 9V power supply to the circuit. A red LED (LED2), in conjunction with zener diode ZD1 (6V), is used to indicate the battery power level.

Resistor R9 limits the operating current (and hence the brightness) of LED2. When the battery voltage is 9V, LED2 glows with full intensity. As the battery voltage goes below 8V, the intensity of LED2 decreases and it glows very dimly. LED2 goes off when the battery voltage goes below 7.5V. Initially, in standby state, both the LEDs are off and the buzzer does not sound. The 230V AC mains is directly fed to mains-voltage detection optocoupler IC MCT2E (IC1) via resistors R1, R2 and R3, bridge rectifier BR1 and capacitor C1.

Illumination of the LED inside optocoupler IC1 activates its internal phototransistor and clock input pin 12 of IC2 (connected to 9V via N/C contact of relay RL1) is pulled low. Note that only one monostable of dual-monostable multivibrator IC CD4538 (IC2) is used here. When mains goes off, IC2 is triggered after a short duration determined by components C1, R4 and C3. Output pin 10 of IC2 goes high to forward bias relay driver transistor T1 via resistor R7.

Circuit diagram:

Mains Supply Failure Alarm Circuit Diagram

Relay RL1 energises to activate the piezo buzzer via its N/O contact for the time-out period of the monostable multivibrator (approximately 17 minutes). At the same time, the N/C contact removes the positive supply to resistor R4. The time-out period of the monostable multivibrator is determined by R5 and C2. Simultaneously, output pin 9 of IC2 goes low and pnp transistor T2 gets forward biased to light up the white LED (LED1).

Light provided by this back-up LED is sufficient to search the torch or generator key. During the mono time-out period, the circuit can be switched off by opening switch S1. The ‘on’ period of the monostable multivibrator may be changed by changing the value of resistor R5 or capacitor C2. If mains doesn’t resume when the ‘on’ period of the monostable lapses, the timer is retriggered after a short delay determined by resistor R4 and C3.

 

 

Source: EFY Mag

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1 25V to 25V To DC power supply

This is a DC power supply circuit.This circuit is based on LM317 Variable Regulator.This Regulator needs at least 28v(DC).Then it will out put 1.25v to 25v DC.So I suppose this would be an important circuit for you all.# 5K ohm Change If you want to change the out put voltage
# This circuit supplies 1.3A.

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Switch Mode 555 Supply

This switch-mode power supply is built around a 555 timer IC. It provides a maximum output voltage of 40 V with a 12-V input voltage. The voltage can easily be set using a Zener diode, and it must be higher than the input voltage (the minimum output voltage is always 12 V). The NE555 is used in an unconventional way here. In the normal configuration, the output of the oscillator IC is low longer than it is high. With the configuration used here, the output can be high for a shorter time than it is low. The NE555 switches FET T1 on and off.When T1 is conducting, energy is stored in L1. When T1 stops conducting, this energy is transferred to C1 and C2 via Schottky diode D1, so the voltage on these capacitors rises.

The voltage is limited by Zener diode D2.If the voltage rises above the Zener voltage,the current through the Zener diode causes T3 to conduct. This reduces the voltage on pin 5 of the NE555, which in turn decreases the relative duration of the high level on pin 3. T1 thus conducts for a shorter interval, so less energy is stored in L1 and the output voltage is stabilised.Current limiting is provided by R6, R5 and T2. If the voltage across R6 is more than 0.6 V, T2 starts to conduct. This drives T3 into conduction, causing the voltage to decrease in order to limit the current.

C5 and R7 provide a soft-start effect.The value of R1 can range from 22 kΩ for an output voltage of 15 V to 10 kΩ for an output voltage of 40 V.For the sake of safety, limit the Zener voltage to a maximum of 40 V. T1 and T2 can be rated for a maximum of 50 V. The FET is not critical; you may already have one in your spare parts bin that can switch enough current. If the coil becomes warm,the core is too small or the wire is too thin.The Schottky diode is the only component that is actually critical. Do not use an ordinary diode, since it will become much to

hot. You’re bound to find a Schottky diode in an old computer power supply (just check for a forward voltage of 0.2 V on the diode range of your multimeter).The supply shown here can deliver approximately 200 W. The input supply voltage can range from 7 V to 15 V.Don’t forget that the maximum voltage the NE555 can handle is 15 V.Finally, this power supply is not short circuit proof. A slow-blow fuse on the 12-V side is recommended.

Author : Martijn Geel Copyright :elektor elector

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UPS Power Supply

This circuit is a simple form of the commercial UPS, the circuit provides a constant regulated 5 Volt output and an unregulated 12 Volt supply. In the event of electrical supply line failure the battery takes over, with no spikes on the regulated supply.
 

Notes:
This circuit can be adapted for other regulated and unregulated voltages by using different regulators and batteries. For a 15 Volt regulated supply use two 12 Volt batteries in series and a 7815 regulator. There is a lot of flexibility in this circuit.
TR1 has a primary matched to the local electrical supply which is 240 Volts in the UK. The secondary winding should be rated at least 12 Volts at 2 amp, but can be higher, for example 15 Volts. FS1 is a slow blow type and protects against short circuits on the output, or indeed a faulty cell in a rechargeable battery. LED 1 will light ONLY when the electricity supply is present, with a power failure the LED will go out and output voltage is maintained by the battery. The circuit below simulates a working circuit with mains power applied: 

Between terminals VP1 and VP3 the nominal unregulated supply is available and a 5 Volt regulated supply between VP1 and VP2. Resistor R1 and D1 are the charging path for battery B1. D1 and D3 prevent LED1 being illuminated under power fail conditions. The battery is designed to be trickle charged, charging current defined as :-
 

(VP5 - 0.6 ) / R1
where VP5 is the unregulated DC power supply voltage.

D2 must be included in the circuit, without D2 the battery would charge from the full supply voltage without current limit, which would cause damage and overheating of some rechargeable batteries. An electrical power outage is simulated below:
 

 

Note that in all cases the 5 Volt regulated supply is maintained constantly, whilst the unregulated supply will vary a few volts.

Standby Capacity
The ability to maintain the regulated supply with no electrical supply depends on the load taken from the UPS and also the Ampere hour capacity of the battery. If you were using a 7A/h 12 Volt battery and load from the 5 Volt regulator was 0.5 Amp (and no load from the unregulated supply) then the regulated supply would be maintained for around 14 hours. Greater A/h capacity batteries would provide a longer standby time, and vice versa.

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