Usb Power Socket Circuit Diagram

Today, almost all computers contain logic blocks for implementing a USB port. A USB port, in practice, is capable of delivering more than 100 mA of continuous current at 5V to the peripherals that are connected to the bus. So a USB port can be used, without any trouble, for powering 5V DC operated tiny electronic gadgets. Nowadays, many handheld devices (for instance, portable reading lamps) utilise this facility of the USB port to recharge their built-in battery pack with the help of an internal circuitry.Usually 5V DC, 100mA current is required to satisfy the input power demand. Fig. 1 shows the circuit of a versatile USB power socket that safely converts the 12V battery voltage into stable 5V.

Circuit diagram:

Fig. 1: Circuit of USB power socket

This circuit makes it possible to power/recharge any USB power-operated device, using in-dash board cigar lighter socket of your car. The DC supply available from the cigar lighter socket is fed to an adjustable, three-pin regulator LM317L (IC1). Capacitor C1 buffers any disorder in the input supply.Resistors R1 and R2 regulate the output of IC1 to steady 5V, which is available at the ‘A’ type female USB socket.

Red LED1 indicates the output status and zener diode ZD1 acts as a protector against high voltage. Assemble the circuit on a general-purpose PCB and enclose in a slim plastic cabinet along with the indicator and USB socket. While wiring the USB outlet, ensure correct polarity of the supply. For interconnection between the cigar plug pin and the device, use a long coil cord as shown in Fig. 2. Pin configuration of LM317L is shown in Fig. 3.

Author : T.K. Hareendran - Source : EFY Mag

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Green USB switch

According to the Energy Saving  Trust, if you add up all the current drawn in standby mode by items such as stereos, TVs, VCRs and DVDs over a year in the UK alone, it amounts to 3.1 million tonnes of CO2 released into the atmosphere.This is without factoring in the current drawn by all the PCs,laptops and their associated peripherals left in standby mode. 

Circuit diagram :

Green USB switch Circuit Diagram

It  is  not  necessary  to  spend  a  great deal of money or time to  make a difference on a personal  level. The circuit described here  is designed for use by laptop or  notebook computers. It will automatically switch off all mains  powered peripheral equipment  including monitor, printer, scanner, TV tuner and USB hub etc  when it detects that the notebook  is switched off. The circuit is quite  straightforward; in addition to an  optocoupler it requires a 12 V  double-pole  relay  with  mains  rated contacts and a small power  supply  for  the  optocoupler.  When the laptop is switched on  5 V appears at the USB socket,  activating the relay and switching  through  the  mains  supply  on K3 and K4. The notebook’s  USB socket is still available to be  used as normal but it’s worth remembering that the optocoupler  takes a few milliamps from the  USB supply and this may cause a  problem if a high-current device  is plugged into the USB socket.  In the case where the laptop has  more than enough USB sockets it may be worthwhile us-ing one of them solely for this  circuit, the extension USB connector K2 would then not be  required. 

The circuit is mounted into a  mains plug enclosure which  provides a socket where the  mains extension strip will be  plugged into. With any luck  there will be sufficient space  to fit the entire circuit into the  mains extension strip enclosure and save the need for a  separate enclosure. The slow-blow 6.3-A fuse (F1) protects  the equipment plugged into  the strip. 

In  addition  to  the  optocoupler  and relay the circuit also has a  ‘freewheel’ diode D1 and a relay  driver formed by T1 and its base  bias voltage divider network R2/ R4. The two ‘snubber’ networks  C1/R3 and C2/R5 reduce the  possibility of arcing which can  occur  when  the  relay  contacts  open (especially with inductive  loads). Capacitors C1 and C2  must be class X2 types which  can handle mains voltage plus any  spikes.  The  power  supply  consists of a small mains trans-former  (12 V,  50 mA),  bridge  rectifier and smoothing capacitor C3. 

The laptop’s mains adaptor itself  can also be switched by this circuit when the laptop is fitted with  its rechargeable battery which  allows the computer to boot up  without a mains supply. The en-tire USB switch circuit draws cur-rent even when it is off but this value  is  tiny  compared  to  the  combined standby current of all  the peripherals. 

Note that parts of this circuit are  connected to the (potentially lethal) mains supply voltage; it is  essential to provide protection  to ensure that nothing can accidentally make contact with these  parts of the circuit. It is also important to observe correct separation between parts of the circuit carrying low voltage and  those carrying the high volt-age. Please observe the electrical Electrical Safety guide-lines which are reprinted in  Elektor  Electronics  several  times a year. 

The  circuit  is  less  suitable  for use with desktop PCs be-cause  the  majority  of  these  machines supply 5 V over the  USB socket even though they  have been shut down via soft-ware. The only way to turn off  in this case is to reach around  the back of the machine and  switch off at the main switch. 

http://streampowers.blogspot.com/2012/06/green-usb-switch.html

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Upgrade Your USB Hub

Problems can arise with USB hubs that are powered from a PC when gadgets plugged into them draw too much current. This is often the case with devices fitted with USB cables that are too long or too thin, causing voltage drop. There’s no need to scrap your old USB hub, however, if you upgrade it using this little circuit and an external power supply. Just cut the 5-V power wire of the USB cable inside the hub and solder a diode (D1) in the pass-through direction. Now connect the 5 V wire from the external power supply to the cathode of this diode. D1 prevents any current from the power supply from flowing back into the PC.

Source by : Streampowers

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Green USB switch

According to the Energy Saving  Trust, if you add up all the current drawn in standby mode by items such as stereos, TVs, VCRs and DVDs over a year in the UK alone, it amounts to 3.1 million tonnes of CO2 released into the atmosphere.This is without factoring in the current drawn by all the PCs,laptops and their associated peripherals left in standby mode. 

Circuit diagram :

Green USB switch Circuit Diagram

It  is  not  necessary  to  spend  a  great deal of money or time to  make a difference on a personal  level. The circuit described here  is designed for use by laptop or  notebook computers. It will automatically switch off all mains  powered peripheral equipment  including monitor, printer, scanner, TV tuner and USB hub etc  when it detects that the notebook  is switched off. The circuit is quite  straightforward; in addition to an  optocoupler it requires a 12 V  double-pole  relay  with  mains  rated contacts and a small power  supply  for  the  optocoupler.  When the laptop is switched on  5 V appears at the USB socket,  activating the relay and switching  through  the  mains  supply  on K3 and K4. The notebook’s  USB socket is still available to be  used as normal but it’s worth remembering that the optocoupler  takes a few milliamps from the  USB supply and this may cause a  problem if a high-current device  is plugged into the USB socket.  In the case where the laptop has  more than enough USB sockets it may be worthwhile us-ing one of them solely for this  circuit, the extension USB connector K2 would then not be  required. 

The circuit is mounted into a  mains plug enclosure which  provides a socket where the  mains extension strip will be  plugged into. With any luck  there will be sufficient space  to fit the entire circuit into the  mains extension strip enclosure and save the need for a  separate enclosure. The slow-blow 6.3-A fuse (F1) protects  the equipment plugged into  the strip. 

In  addition  to  the  optocoupler  and relay the circuit also has a  ‘freewheel’ diode D1 and a relay  driver formed by T1 and its base  bias voltage divider network R2/ R4. The two ‘snubber’ networks  C1/R3 and C2/R5 reduce the  possibility of arcing which can  occur  when  the  relay  contacts  open (especially with inductive  loads). Capacitors C1 and C2  must be class X2 types which  can handle mains voltage plus any  spikes.  The  power  supply  consists of a small mains trans-former  (12 V,  50 mA),  bridge  rectifier and smoothing capacitor C3. 

The laptop’s mains adaptor itself  can also be switched by this circuit when the laptop is fitted with  its rechargeable battery which  allows the computer to boot up  without a mains supply. The en-tire USB switch circuit draws cur-rent even when it is off but this value  is  tiny  compared  to  the  combined standby current of all  the peripherals. 

Note that parts of this circuit are  connected to the (potentially lethal) mains supply voltage; it is  essential to provide protection  to ensure that nothing can accidentally make contact with these  parts of the circuit. It is also important to observe correct separation between parts of the circuit carrying low voltage and  those carrying the high volt-age. Please observe the electrical Electrical Safety guide-lines which are reprinted in  Elektor  Electronics  several  times a year. 

The  circuit  is  less  suitable  for use with desktop PCs be-cause  the  majority  of  these  machines supply 5 V over the  USB socket even though they  have been shut down via soft-ware. The only way to turn off  in this case is to reach around  the back of the machine and  switch off at the main switch. 

http://streampowers.blogspot.com/2012/06/green-usb-switch.html

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USB Car Charger Adapter

This USB car charger adapter project is a DC DC power converter that safely converts the 12V car battery voltage into stable 5V. This USB car charger circuit can be used to supply power from a car cigar lighter socket to a portable device that require a 5 volts . This circuit makes it possible to power/recharge any USB power-operated device, using in-dash board cigar lighter socket of your car.

USB Car Charger Adapter Circuit diagram

The DC supply available from the cigar lighter socket is fed to an adjustable, three-pin regulator LM317L (IC1). R1 and R2 resistors regulate the output of IC1 to steady 5V, which is available at the ‘A’ type female USB socket. Red LED1 indicates the output status and zener diode ZD1 acts as a protector against high voltage.As you can see in the circuit diagram , the circuit is very simple and require just few common cheap components .Because this circuit not require many components , you can put all components in the cigar plug socket .

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USB Switch Schematic Circuit

Anyone experimenting or developing USB ported peripheral hardware soon be comes irritated by the need to disconnect and connect the plug  in order to reestablish communication with the PC. This process is necessary for example each time the peripheral equipment is reset or a new version of the firmware is installed. As well as tiresome it eventually leads to excessive contact wear in the USB connector. The answer is to build this electronic isolator which disconnects the peripheral device at the touch of a button. This is guaranteed to reduce any physical wear and tear and restore calm once again to the workplace. 

Circuit image :
 

USB Switch Schematic Circuit Image

The circuit uses a quad analogue switch type 74HC4066. Two of the switches in the package are used to isolate the data path. The remaining two are used in a classic bistable flip-flop configuration which is normally built using transistors. A power MOSFET switches the power supply current to the USB device.  Capacitor C2 ensures that the flip flop always  powers-up in a defined state when plugged  into the USB socket (‘B’ in the diagram). 

The  peripheral device connected to USB socket ‘A’  will therefore always be ‘not connected’ until  pushbutton S2 is pressed. This flips the bistable, turning on both analogue gates in the data lines and switching the MOSFET on. The  PC now recognises the USB device. Pressing  S1 disconnects the device.

Circuit diagram :

USB Switch Schematic Circuit Diagram

The circuit does not sequence the connections as a physical USB connector does; the power supply connection strips are slightly longer than the two inner data carrying strips to ensure the peripheral receives power before the data signals are connected. The electronic switch does not suffer from the same contact problems as the physical  connector so these measures are not required in the circuit. The  simple circuit can quite easily be constructed on a small  square of perforated strip-board. 

The design uses the 74HC(T)4066 type analogue switch, these have  better characteristics compared to the standard 4066 device. The USB switch is suitable for both low-speed (1.5 MBit/ s) and full-speed (12 MBit/s) USB ports applications but the proper ties of the analogue switches and perf-board construction  will not support hi-speed (480 MBit/s) USB operation. 

The IRFD9024 MOSFET can pass a current of  up to 500 mA to the peripheral device with-out any problem.

Source : www.ecircuitslab.com

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