I agree it is a win on price but it is NOT what you want. It states: "TPS63020 power module automatic buck 2.5V 3.3V 4.2V 5V lithium battery low ripple" then later it tells you it can be converted but no directions. Nowhere does it tell you it does both concurrently or how to change. You want a Boost Converter which will boost the voltage for you. A buck converter lowers the voltage. A SEPIC (Buck/Boost) does whatever is needed to maintain the output voltage at the setpoint. I normally use SEPIC converters especially when powering with batteries.
I think I have a decent chance of getting it to work. They provide a number of details in the description. The following snip is from the description section:
On the order page you select what 'colour' of module to buy. The options are 2.5v, 3.3v, 4.2v and 5v.
I've dealt with some of these type of aliexpress electronics before, some success, others not. But this seems to have more documentation than normal, which in itself is laughable.
A SEPIC (Buck/Boost) does whatever is needed to maintain the output voltage at the setpoint. I normally use SEPIC converters especially when powering with batteries.
Do you have any recommendations (Cheaper than the Pololu one?)
SIM modules are designed to run on a single LiPo battery. So you're saying you first want to boost a voltage to 5volt, and then drop it to 3.7volt again?
Did you calculate the idle current of a boost converter for two years.
Leo..
I use Allile Express as you say they are cheaper then most. For the most part I have never had problems with the products. The descriptions are the problem. I purchased a bunch of buck/boost converters to only find out when I got them they were boost only. The whole return process took about two weeks. They sent the label via email, I printed it and mailed it about two days later. About a week later I got a notice it had been returned and the next day I found my account had been credited but the notification of that credit took two more days. You have to read the descriptions very carefully and do not assume anything.
I know a lot of people badmouth the chine semiconductors but in reality they are some of the best in the world. Currently China is the world's largest semiconductor market, representing 31.4% of worldwide final sales or US$180billion out of US$574billion in 2022. There manufacturing should reach $200billion by the end of this year.
So you're saying you first want to boost a voltage to 5volt, and then drop it to 3.7volt again?
In this instance, that assumption is incorrect - the module has no 3.3v or 3.7v or other power inputs other than 5v. It has a Vreg on board the module to step it back down to 3.3v but I have no interest in modifying the board to bypass the step down Vreg.
I appreciate your time to respond, but in this instance i'm really only after an answer to the question that I asked.
Did you calculate the idle current of a boost converter for two years.
I did not calculate it, I read it off the datasheet but i'm sure that's what you meant. For the two products that I posted links to, the sleep current is not an issue at all. Although if it was a problem I know I can add a MOSFET in place and turn it off for the sleep cycle.
Cheers
I use Allile Express as you say they are cheaper then most. For the most part I have never had problems with the products. The descriptions are the problem. I purchased a bunch of buck/boost converters to only find out when I got them they were boost only. The whole return process took about two weeks. They sent the label via email, I printed it and mailed it about two days later. About a week later I got a notice it had been returned and the next day I found my account had been credited but the notification of that credit took two more days. You have to read the descriptions very carefully and do not assume anything.
I agree with your opinion, i've had most (90-95%) aliexpress/alibaba products work fine and had a similar experience as you for faulty products. Only two products didnt arrive at all and I was paid my measly $3 back.
I guess if no one has an alternative to suggest, i'll just go and buy these aliexpress ones and
a. Validate that I know how to get what I want out of them (5v & 2A)
b. Torture test them to give some confidence that they'll last 2 years with a total on time of 12.2 hours. (60 seconds per day for 2 years)
Not necessarily a knockoff, and as you said, even if it is, it may still work OK.
What you'd have to look into is whether the module will indeed reliably deliver 2A under your specific operating conditions. Verify with the TI datasheet and order a module to test with.
Note the very high quiescent current with your input voltage.
The only/main thing that worries me are the tantalum caps on that AliExpress module, but a lifespan of 2 years shouldn't be a problem even for those. It if works the first week, I don't doubt it'll work for the remainder of the 2-year period as well.
There are plenty of boost controllers and modules out there; your choice certainly isn't limited to these two. They're a generic item; just shop around a little, purchase a couple to play with and then choose what works best.
But you have specific requirements and a certain expectation w.r.t. service life. Qualification of parts is something that's part & parcel of project management.
I tell ppl to place the regulator in circumstances that are close to the deployment scenario, and test test test as specifications on these tend to be aspirational.
I have a bunch of 3A buck regulators that I would trust to deliver 1A. At 2A they are already too hot, at 3A they oscillate, something shuts them down until they cool off (?) dunno exactly.
So
Validate and
Torture test
for sure. I wish paying more was a guarantee of anything. That said, I have had good luck with units from Pololu, whose specs may still be aspirational. Derate somewhat, but don't get too much over calapaxitt as you might be running the moduke in a less efficient portion of its volts and amps ability.
What I think is happening is the AliExpress vendors purchase from a few vendors and mark them up whatever they want. It appears these vendors also ship the products for them. The description is up to the vendor who generally do not know an electron from a golf ball. A prime example is what you are finding with buck/boost units.
