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USB 5V to 12V DC-DC Step-Up Converter by LT1618

Posted Jan 10, 2012 at 12:45 pm
Figure:1

Figure 1 

This is a 5V to 12V DC-DC step-up (boost) converter circuitry that is especially ideal for the USB powered applications. First of all a USB port has two current supply modes. Before detecting the connected device, it supplies maximum 100mA to the load. After recognizing the device, it increases the output current up to 500mA. In this circuit, controller (LT1618) also provides two input current modes. 100mA and 500mA input modes can be selected by the user.

Output currents are limited due to the increased potential difference at the output. When the demand of the load increases, output voltage will start to decrease. For example, if the circuit operates in the 100 mA input mode, when the load is 35 mA, the output voltage will be kept at 12V. But if the load increases to 50 mA, output voltage will reduce to 8V to maintain the constant 100 mA input current.

Read More Source: http://www.linear.com

Tags: USB, serial,

Comments on this post:

By Lucas 0Score: 

4 years ago:  Can this be bought?

By ping lacson 0Score: 

4 years ago:  I haven't tried this but I think it's worth a try. Maybe I'll just make sure that the zener diode is of good quality just to make sure of no over voltage. Thanks dude!

By Khaled 0Score: 

3 years ago:  Can you customise this to use 5v usb power to drive 12v 3.5" sata HDD?

By josh smith 0Score: 

3 years ago:  which input modes is better for the LT1618? should I choose the higher one or the lower? please advice...

By DANIEL 0Score: 

3 years ago:  hi i got a problem, im trying to make a laptop cooler, and i just did it with 5x 120mm fans each of 12v 170ma. i just did a circuit to convert 5v to 12v and it does work on normal power when i connect it to a 5v adapter it boost it to 12v but when i connect the fan this funs run at 3.5v = to 1/3 of 12v who know why is this happening?

By james 0Score: 

3 years ago:  because you need more power youve overstepped you amperage reduce fans from 5 to 2 or 3

By Evgeni 0Score: 

2 years ago:  Hello everyone can i supply two fans 0.1A 12V from my USB with this

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