# Looking for a quick and easy way to boost +5VDC to +24VDC

I am looking for a simple IC solution how to boost +5VDC to +24VDC 1A. Requirements:

• THT (the project is on a 2.54mm(0.1") experimental breadboard)
• low-cost (this is a hobby project, so arround $5 for the whole converter system) • simple (fewest external elements) • has been around for a while (most recent chips are delivered to my country mainly by the Farnell, charging high transport prices). Is this attainable? What are a part number or two, that I can toss in the local electronics shop and get the device working by the afternoon? • Pretty good discussion. I'm being waiting for the answers. – Standard Sandun Jan 8 '13 at 11:09 • Your 1A requirement makes this sort of non-trivial. It means that the switching element has to switch in the order of 10A! (taking overall efficiency and on-off time into account). That means you need a switcher chip, pass FET, inductor, diode, some assorted support stuff, and a very careful layout. – Wouter van Ooijen Jan 8 '13 at 11:37 • @ Wouter van Ooijen, what alternative would you propose, fitting the above requirements? I have wall power (which I would like to avoid for safety reasons) and a computer PSU(hence the 5VDC). Also, I could tap the +12VDC rail Would this make the design more peasantry?. – Vorac Jan 8 '13 at 12:23 • Yes, absolutely use the 12V rail. It might not be quite non-trivial but it cuts the input current requirements significantly. 24V DC 1A is 24W. If we keep this simply to P=IV and ignore switching efficiency and a saftey margin above 1A for your max output, 24W/5V=4.8A. Using the 12V rail, 24W/12V=2A. Now keep in mind that if you have a 1A load you want to be able to output more than 1A, probably up to 1.5A (36W) to be safe. Switching regulators are generally about 70-90% efficient, so you're losing another ~9W there = 45W total to design for. 45W/5V=9A. 45W/12V=3.75A. – Joe Baker Jan 8 '13 at 17:24 • Why was the question closed? Deriving various voltages from a efficient end cheap(due to economy of scale) computer PSU is an interesting topic. If it is because of the link to a concrete shop - that is for illustrative reasons only, I can remove it, no problem! – Vorac Jan 9 '13 at 9:29 ## 3 Answers Note: This solution can not provide 1 Ampere output while boosting from 5 Volts, as pointed out by @markrages. Also, the product mentioned is not suggested to be operated beyond a step-up ratio of 1:3, i.e. up to 15 Volts from a 5 Volt source. Hence, this answer does not meet the criteria specified in the original question. With the amended 12 Volt source, it would work. As has been pointed out by @Wouter van Ooijen, one is unlikely to find a simple single-IC solution for boosting a 5 Volt DC source to 24 Volts at 1 Ampere. An alternative that fits the specified budget but not the full requirements is a pre-built adjustable DC-DC boost module such as this one on eBay for$4.49 with free international shipping.

The module uses the Texas Instruments LM2577 step-up voltage regulator, and incorporates the required inductor and adjustment preset on the board.

Input voltage ranges from 3.5 to 30 Volts, and output can be adjusted from 4 to 30 Volts, as long as the output is not set to more than 3 times the input voltage.

Searching on eBay and other sites may yield lower prices for these modules.

• That won't supply 24V @1A. The input current is limited to 2A continuous. That's 10W in. So at perfect efficiency, that's 416 mA out. – markrages Jan 8 '13 at 16:50
• ebay page: "Continuous input current: 2A (good ventilation and cooling conditions the output voltage and input voltage ratio is not greater than 3)" – markrages Jan 8 '13 at 18:14
• For a 1A output @24V, you need at least 4.8A input. But the switch in LM2577 is only rated for 3A per the datasheet. – markrages Jan 8 '13 at 18:18
• @markrages Fair point which I had missed entirely... Editing my answer to reflect this. Thanks. – Anindo Ghosh Jan 8 '13 at 18:34
• @RyanWhite 470 uH inductor – Anindo Ghosh Jul 1 '19 at 12:50

I'm pretty impressed at Roman Black's simple +5V to +13V voltage boost circuit that uses only extremely common low-cost components.

It appears to me that replacing the 13V zener with a 24V zener and some relatively minor part value tweaking would produce a +5VDC to +24VDC booster. It also appears to me that all of the components in this circuit are available in through-hole packages (THT) which some people seem to think is easier to assemble. A few people can get a (low frequency) switching regulator working on a solderless breadboard. (Emre, Roman Black, J. B. Calvert, Bob Pease, etc.). Alas, solderless breadboards are notorious for causing problems with switching voltage regulators. ( Bob Pease, again. )

A full 1 A output would require swapping out most of the components with higher-current components, and increasing the current limit by reducing the resistance of R2. It might also need a few heat sinks, since it's "only" 72% efficient. There are several ways to improve the efficiency, but I all the ones I can think of off the top of my head would make it more complicated.

TI's selector gives a variety of choices with those requirements including with a LM3478/88/81. They cost about \$5 in parts, but that isn't in small quantities and with shipping.