Dual USB Power Supply Controller Using ISL6185

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This is a very simple dual USB power supply controller using the isl6185 USB power controller family. Dual USB power supply electronic project that provides fully independent overcurrent (OC) fault protection for two or more USB ports.

Dual USB Power Supply Controller Circuit Diagram:

This product family consists of sixteen individual functional product variants and three package options and is operation rated for a nominal +2.5V to +5V range and specified over the full commercial and industrial temperature ranges.

Each ISL6185 type incorporates in a single package two 71mΩ P-channel MOSFET power switches for power control and features internal current monitoring, accurate current limiting and current limited delay to turn-off for system supply protection along with control and communication I/O.
The ISL6185 family offers product variants with specified continuous output current levels of 0.6A, 1.1A, 1.5A or 1.8A. Due to all integrated features this power supply circuit is very easy to be designed and require few electronic parts.

12V / 230V 50Hz Square Wave Inverter Using by 555

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The DC/AC power inverter can be useful anywhere where you do not have mains outlet, for example a car, trailer or cottage. It can power mains appliances like radios, tape recorders, DVD players, televisions, electric shavers, fluorescent lamps or cell phone charger. The maximum load depends on the transformer, transistors, and the size of the heatsink.

The source of 50 Hz frequency is a well known 555 timer. The frequency is set by the resistance of Rx and capacitor Cx. As the switches two N-type MOSFETs are used. One is driven directly from the 555 IC, the other through an logic inverter with BC547. Transformer is a mains one with two secondary windings 12V and must be designed for the maximum load required. The heat sink of the two power transistors must have heatsink according to the load.

12V / 230V 50Hz Square Wave Inverter Circuit Diagram:

They are mounted on isolation pads. You can also use separate heatsink for each transistor and no isolation pads, but then the heatsinks must not touch each other and must not be grounded. The 12V supply must be sufficiently hard, the supply voltage should be in the range of about 11 - 14V. Use the proper fuse in series with the power input! In products that are not dependent on the frequency of 50Hz, it is possible to use a higher frequency, about 100 - 300Hz. This reduces the standby power.

case TO220 MOSFET pinout - (same for all transistors)

The frequency can be adjusted by changing the values of Rx and Cx. It is also easy to modify the system from 50Hz to 60Hz just by reducing the Rx value by 1/6 (from 120k to 100k). MOSFET can be IRFZ44 for loads up to 200W, IRFZ48 up to 350W or IRF3205 up to 600W. For output above 600 watts is possible to combine multiple transistors IRF3205 in parallel. Very good parameters has also IRF1405. This type of DC/AC power inverter has non-stabilized output voltage, square wave.

Warning:
When working with the power inverter be careful - the output voltage is lethal, although input is safe voltage. Output voltage is isolated from the ground, but if you touched both output terminal the voltage is similarly dangerous as the mains voltage. Everything you do at your own risk. Author does not take responsibility for any of your harm.

2 Watt Switching Power Supply

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Build a simple and small 2 Watt Switching Power Supply Circuit. In this small switching power supply, a Schmitt trigger oscillator is used to drive a switching transistor that supplies current to a small inductor. Energy is stored in the inductor while the transistor is on, and released into the load circuit when the transistor switches off.

2 Watt Switching Power Supply Circuit Diagram:

The output voltage is dependent on the load resistance and is limited by a zener diode that stops the oscillator when the voltage reaches about 14 volts. Higher or lower voltages can be obtained by adjusting the voltage divider that feeds the zener diode. The efficiency is about 80% using a high Q inductor.

Varying Brightness AC Bulb

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How to build varying brightness AC bulb circuit. In this circuit, an SCR is used to slowly vary the intensity of a 120 volt light bulb by controlling the time that the AC line voltage is applied to the lamp during each half cycle.

Varying brightness AC Bulb Circuit Diagram:

Caution:

The circuit is directly connected to the AC power line and should be placed inside an enclosure that will prevent direct contact with any of the components. To avoid electrical shock, do not touch any part of the circuit while it is connected to the AC power line. A 2K, 10 watt power resistor is used to drop the line voltage down to 9 volts DC. This resistor will dissipate about 7 watts and needs some ventilation.

Operation:

A couple NPN transistors are used to detect the beginning of each half cycle and trigger a delay timer which in turn triggers the SCR at the end of the delay time. The delay time is established by a current source which is controlled by a 4017 decade counter. The first count (pin 3) sets the current to a minimum which corresponds to about 7 milliseconds of delay, or most of the half cycle time so that the lamp is almost off. Full brightness is obtained on the sixth count (pin 1) which is not connected so that the current will be maximum and provide a minimum delay and trigger the SCR near the beginning of the cycle. The remaining 8 counts increment the brightness 4 steps up and 4 steps down between maximum and minimum. Each step up or down provides about twice or half the power, so that the intensity appears to change linearly. The brightness of each step can be adjusted with the 4 resistors (4.3K, 4.7K, 5.6K, 7.5K) connected to the counter outputs.

The circuit has been built by Don Warkentien (WODEW) who suggsted adding a small 47uF capacitor from ground to the junction of the current source transistor (PNP) to reduce the digital stepping effect so the lamp will brighten and fade in a smoother fashion. The value of this capacitor will depend on the 4017 counting rate, a faster rate would require a smaller capacitor.

Build a Low Power Variable Voltage Converter

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Using electronic diagram below can be made a voltage converter that allows laps positive voltage of existing power sources, or convert it into a negative voltage.

New supply is electrically isolated from the source through the ferrite transformer wound on a torus G2-3FT12. Primary winding consists of 30 turns. Number of turns in the secondary, n, is calculated using the equation: n = 30 Uo / Ui, where Uo is the desired voltage and Ui is the input voltage. Add to compensate pieriderior 20.05.10 turns. If the output voltage is higher, it can always reduce Pi. Both coil windings can be enamelled copper wire with a diameter of 0.3 mm.

Low Power Variable Voltage Converter Circuit Diagram:

The transformer is controlled by a gate CMOS Schmitt trigger and Do with transformed into a rectangular signal generator R1 and C1.

Additional current to charge C1 is provided by R2 and Pi, which controls the duty cycle of the rectangular signal. The signal frequency is about 220 kHz and fill factor or should be less than 0.5.

When T1 is opened, some of the energy is transferred to the secondary winding and some is stored in the magnetic circuit. When T1 conduction ceases, the magnetic field energy transfer in the secondary winding.

The current through Q1 will increase dangerously if secondary task is too big. Average current through the primary should not exceed 150. The report gave the scheme, secondary task can not be less than 80 ohms.
Besides excessive loads should also avoid working without load.

Converter efficiency at a supply voltage of 15 V is about 65%. The low current load, it decreases to about 50%. Efficiency also decreases when the supply voltage is lower than indicated. The current drawn from the source of 15 V for a load of 80 ohms is about 165 mA.

LED Flasher Using Transistor

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This simple LED flasher using transistor, an LED flasher can be made that can be used for example to simulate the existence of an alarm mounted in a vehicle driver.

LED Flasher Using Transistor Circuit Diagram:

The circuit is a relaxation oscillator built around transistor T1 Unijunction that provides repeated pulses with a duration of a few milliseconds, Darlington transistor T2. When the contact is closed the LED is blocked through T3.

The circuit has a current actual consumption of only 2 mA. Resistors R1 and R3 will be resized to compensate for higher tolerances resulting from manufactured Unijunction transistors. Do not use in the assembly of high power LEDs (current peaks should not exceed 250 mA).

Bicolor LED Driver Uses Two Leads

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This circuit detects the correct closed condition of the left and right side bags in a motorcycle companion. The bag has two locks that you must close for protection.

Bicolor LED Driver Uses Two Leads Circuit Diagram:

When you push the two momentary SPDT (single-pole/double-throw) switches, they sense the correct closed bag. One bicolor red-and-green LED indicates the bag’s status, with the red color showing the open-bag condition. To illuminate the LEDs, you must reverse the polarity of the applied voltage to the LED to change the color (Table 1).

Diodes D₁ and D₂ and resistor R₁ form a discrete OR gate. When either pushbutton switch connects to 12V, the voltage at Point A is positive with respect to Point B. Transistor Q₁ conducts, letting current illuminate the red LED. When neither switch connects to 12V, neither diode conducts. The base of Q₁ pulls low through R₁ and R₄, indicating that the bags are closed. Thus, the green LED illuminates as current passes through it and through R₁ and R₂.

The diode, transistor, and resistor values are not critical, and you can adjust them according to your needs. You can also replace the bicolor LED with two discrete LEDs of different colors placed back to back.

Soft Start For Switching Power Supply

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The output voltage from the input voltage is an interesting property is appreciably lower switching power supply: It's produced by the current is smaller than the output current. However, input power (UI), of course, is higher than the output power. On the switch when low input voltage is too low, the regulator try to draw full current will need to be looked at another aspect.

Supply can not cope with it, if it fails or the fuse blows. It (On / Off by input) switch to disable the regulator reduced, so is advisable. Related capacitor is charged until. If the regulator starts to draw current, charging current overload voltage source which is not already on a level declined.

Soft Start For Switching Power Supply Circuit Diagram:

The circuit in the diagram provides an output voltage of 5 V and is supplied by a 24 V source. The regulator need not be disabled until the capacitor is fully charged: when the potential across the capacitor has reached a level of half or more of the input voltage, all is well. This is why the zener diode in the diagram is rated at 15 V. Many regulators produced by National Semiconductor have an integral on/off switch, and this is used in the present circuit.

The input is intended for TTL signals, and usually consists of a transistor whose base is accessible externally. This means that a higher switching voltage may be applied via a series resistor: the value of this in the present circuit is 22 kΩ. When the voltage across the capacitor reaches a level of about 17 V, transistor T1 comes on, whereupon the regulator is enabled.

Electronic Fuse for DC Short Circuit Protection

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Make a simple and easy electronic fuse for dc short circuit protection. This is an electronic fuse that protects the load against short circuit. Relays must be chosen with a voltage value equals to the input voltage. Don’t omit using the 100uF capacitor with appropriate voltage value with respect to the input voltage. If you can’t provide, you can use C106 instead of BRX46.

Electronic Fuse for DC Short Circuit Protection:

You can adjust the current with using 10K potentiometer. If you will use the fuse with very high currents, lower the 0R6 5W resistor value (ex. 0R47, 0R33, 0R22 or 0R1). Watt value of the resistor should be increased also.

Flat Battery Indicator

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This small circuit was developed to monitor the battery in a model hovercraft. The lift in the model is produced by an electric motor driving a fan. To avoid the possibility of discharging the rechargeable battery pack too deeply, the design lights a conspicuous LED mounted on the model when a preset threshold voltage is reached. The circuit only uses a few components, which helps keep the total weight of the model down. The circuit connects to the model only across the two points where the voltage to be monitored can be measured. These also supply power to the circuit.

The best place to connect the circuit is not at the battery terminals, but rather at the motor connections. The circuit is suitable for use with nominal battery voltages of 4.8 V to 9.6 V (four to eight 1.2 V cells). For example, if there are six cells in the battery, its nominal terminal voltage will be 7.2 V. A discharge threshold voltage of around 1 V per cell is appropriate, which means that for six cells the threshold is 6 V. We now need to set the voltage UZ across the adjustable Zener diode D1 (an LM431) to about 0.5 V less than the threshold voltage at which we want LED D2 to light.

Flat Battery Indicator Circuit Diagram:

This voltage is controlled by the choice of the value of resistor R1. As indicated in the circuit diagram, this is done with the help of a trimmer potentiometer (R1.A) with a fixed resistor (R1.B) in series. Using the suggested values (10 kΩ for both the potentiometer and the fixed resistor) allows the discharge threshold voltage to be set between about 5.5 V and 8 V. For lower or higher voltages R1.B should be made correspondingly smaller or larger. Once the desired value of UZ has been set the total resistance (R1.A plus R1.B) can be measured and a single fixed-value resistor of this value substituted at R1.

In the example mentioned of a six-cell battery, a voltage of 7.2 V will appear at the emitter of T1 when the battery is charged. At its base is UZ, which should be 5.5 V (6 V – 0.5 V) in the case of a discharge threshold voltage of 6 V. As long as the battery voltage remains at least 0.5 V higher than UZ, T1 will conduct and T2 will block, with the result that LED D2 will not light. If the battery voltage should fall below about 6 V (UZ + 0.5 V), T1 will block, T2 will conduct and LED D2 will light. To ensure stable operation of the circuit R6 provides a small amount of switching hysteresis. By adjusting the resistor value between 100 kΩ and 220 kΩ the amount of hysteresis can be varied.

The current drawn by the circuit itself is less than 5 mA (as measured with a battery voltage of 7.2 V). When the LED lights an additional 10 mA (the LED current) is drawn, for a total of around 15 mA. The adjustable Zener diode can be replaced by a ﬁxed Zener with a voltage 0.5 V less than the desired threshold. Resistors R1 and R2 can then be dispensed with. A ﬂashing LED can be used for D2 (without series resistor R7). An acoustic alarm can be provided by replacing D2 and R7 by a DC buzzer with a suitable operating voltage.

Simple and Easy Build PIR Motion Detector

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A very simple PIR motion detector circuit can be designed using this diagram. This project PIR sensor PIR motion detector circuit, operational amplifier, a sound generator circuit and use some other common electronic components.

The op-amp IC1D shapes the frequency response to amplify those frequencies produced when motion is detected and rejects all others, such as those due to noise or slow temperature changes. As motion is detected, the voltage at the output will change and trigger either IC1C or IC1B.The op-amps IC1A, IC1B and IC1C are configured as voltage comparators.

PIR Motion Detector Circuit Diagram:

When IC1D outputs a voltage lower than 1.41V, it will force pin 2 of IC1 high. When IC1D outputs a voltage higher than 1.67V, it forces pin 8 and pin 2 of IC1 to go high. A high in with one of these cases causes the output to go low and allows C9 to discharge through IC1A. The discharging of C9 will pull pin 6 of IC2 low and trigger the sound generator.

The Passive Infrared Sensor (PIR) used in this alarm circuit can be LHI-954 , KDS245 or other similar type .As sound generator you can use a HT2810 or HT2812 sound generator integrated circuit .This motion detector alarm circuit requires two DC voltage 5 volts for almost all power connections and 9 volts for the sound generator circuit .

How to Build a Automatic Lighting Controller

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How to build a automatic lighting controller circuit. The governor following is intended to regulate the light intensity incandescent 220 V. The components in a relatively few, which means it can easily be mounted onto a small plate. After the build, we recommend you place it inside the box which is flush mounted switch ON / OFF the lamp. Setting the switch to ON, the lamp will light after about 400 msec, a delay is probably negligible.

Automatic Lighting Controller Circuit Diagram:

But when the state enters the ON OFF, then mesolathei a period of 20 sec, the brightness of the lamp remains unchanged to start falling out soon after. The last feature is particularly useful when we want to have a little time from the moment you 'close' switch. Once the switch S1 set to ON, the capacitor C2 begins to charge through R1, C1 and bridge D1-D4. The Zener diode D5 limits the voltage across the capacitor to about 15 n. After awhile, the diode D6 LED illuminates, causing the appearance of a significant drop in voltage across R3.

The change in voltage results in stimulation of Triac TR1, which in turn lit the lamp is connected to K2. We note that the resistor R3 is a type of LDR, the price that depends on the intensity of light falling on it. When the switch is moved to OFF, the capacitor C2 will discharge through R 1, R2 and D6. During discharge, the LED D6 reduces the brightness continuously, which causes a gradual decrease in voltage across R3. The increasing resistance of R3 is causing in turn change the firing angle of the Triac, which eventually results in a smooth decrease in brightness of the lamp.

The time required for complete extinction of the lamp is defined by the regulatory P1 and directly dependent on the time constant R2-C2. The circuit works properly only if it falls on the R3 only light diode O6 rather diffuse room light. The type of LDA is not critical. Choose a length with a 5mm.

Full Fault Protection 5 Volt Regulator Using by NCP3155

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This is a very simple 5 volt regulator circuit project using by NCP3155 DC DC synchronous switching regulator with fully integrated power switches and full fault protection. The switching frequency of 1 MHz and 500 kHz allows the use of small filter components, which results in smaller board space and reduced BOM cost.

5 Volt Regulator Using by NCP3155 Circuit Diagram:

This is a very simple 5 volt regulator circuit project drives high−side and low−side N−channel power MOSFETs. The NCP3155 incorporates an internal boost circuit consisting of a boost clamp and boost diode to provide supply voltage for the high side MOSFET gate driver. This regulator also integrates several protection features including input under-voltage lockout (UVLO), output under-voltage (OUV), output overvoltage (OOV), adjustable high−side current limit (ISET and ILIM), and thermal shutdown (TSD).

This circuit requires few external electronic parts and can be configured very easy. In put voltage that is required by this power supply circuit must be between 10.8 and 24 volts an can provide a fixed output voltage between 1.2 volts up to 5 volts by changing a simple resistor.

Note:

The maximum current that can be provided by this regulator circuit is up to 3A.