A few months ago we received accidentally some TPS61028DRCR ICs instead of the parts we ordered as a result of a misdelivery. After contacting the supplier we finally got the PCF2129A ICs we ordered and we were allowed to keep the wrongly delivered TPS61028DRCR ICs.
So we decided to actually try to use them. The idea was to be able to run microcontroller circuits on a single 1.5V alkaline cell. The result is the above mini boost converter. We designed our PCB based on the recommended PCB layout in the TPS21028DRCR datasheet.
Please note that the input is not reverse polarity protected. If reverse polarity protection is necessary, you can use a 1N5817 schottky diode or consult application note SLVA139 from Texas instruments if you need a more advanced solution. The battery low indication (marked "Batt" on the PCB) is high when battery level is OK. When the battery level goes below 0.9V, this output switches to ground. Please note that the battery low output only can sink about 100 microamps max. so it is not suited to drive an LED.
If you decide to build this yourself based on our PCB files, please note that the TPS61028DRCR measures only 3 x 3 mm and it can be quite a challenge to solder it to the PCB.
- Can drain a 1.5V alkaline cell to 0.9V while delivering 5V @200mA at the output.
- Can be used to boost a 3.3V rail to 5V @500mA.
- Input voltage range 0.9 - 6.5 V.
- 5V output and 3.3V output version.
- Battery low signal when input voltage drops below 0.9V (optimized for 1.5 V alkaline cell).
- High efficiency, typical 96%.
- Low power consumption when no output load is present.
- Battery powered equipment.
- Solar powered equipment.