Hi,
I need a DC/DC step-up chip from 3.7V, coming from a LC26650 battery, to 5V. The load needs 5V, and the current varies from 80mA to 220mA. I thought this step-up converter, XC9142B50, would do the job, but I can't make it work. I have changed the XC9142B50 chip, the caps, and the inductor but it doesn't work. I get the 3.7V of the battery at the output. I have checked the wiring like 10 times and nothing. The wiring is very simple, so I don't know what's wrong. The load works fine with 5V coming out of a power supply.

Can you please recommend another chip that I could use? Any help is greatly appreciated. Thanks.

 

Your schematic clip from the datasheet does not show what you are doing with the CE (Chip Enable) pin. Please tell me that you did not leave it floating.

 

Your schematic clip from the datasheet does not show what you are doing with the CE (Chip Enable) pin. Please tell me that you did not leave it floating.

No, I connected CE to the battery.

 

Post a clear photo of your construction.

 

According to Table 1 in the datasheet you may need a load on the output.

 

According to Table 1 in the datasheet you may need a load on the output.

When I put the load nothing happens.

 

Post a clear photo of your construction.

It just the schematic I posted above with Vbat connected to CE. The battery is the LC26650 .

 

Data sheet or part number for the inductor, please.

 

Data sheet or part number for the inductor, please.

These power boosters have kicked me in the rear so many times, and most of the time, the problem is with the inductor I'm using. This time I am using a cheap inductor that is not wirewound, I found in my drawers. I'm ordering the two inductors recommended in the datasheet. I'll keep you posted.

 

the problem is with the inductor I'm using.

Very often on the forms people pick a 4.7uH inductor without looking at any other specification. It should not saturate at the max current of the "switch" in the IC. (this is not the output or input average current) This type of supply the input current is high than the output current. I think you are on the right track now.

 

Hmm, I used the inductor recommended in the datasheet and the booster output voltage went up to 5V. The datasheet says that the booster can provide up to 500mA. My load has a maximum current load of 220mA.

I smoked the booster chip with my first trial with the recommended inductor. Even though the booster can have a load of 500mA, I smoked the chip with a load of 220mA. The load is very inductive, so I'm only guessing that might be the problem. The load works fine with a regular power supply.

I put a diode between the LC26650 battery and the inductor in the schematics I posted before, and the chip doesn't get fried. When I connect the load, the output voltage goes down to 1.3V. If I disconnect the load with the diode still connected, and the output voltage goes up to 5V.

These DC/DC boosters don't like me too much . What do you recommend? How can I make the load less inductive, assuming that is the problem? Thanks.

 

Okay, I keep burning these boosters. Now, I tried a TPS613222ADBVR booster from Texas Instruments. This booster can take a load of up to 1.8A. To my surprise, when I connected the load, this chip got fried. My load is a DLP-RFID2, which is an NFC 13.56MHz RFID module. The load works as expected when connected to a regular power supply. I'm thinking that these boosters don't like a very inductive load.

What do you think might be the problem? I'm just using the typical recommended circuit with the recommended inductor. I have no clue what the issue might be other than the load being too inductive with rapid changes in load current. Any help or clues are highly appreciated.