Hello,
On the datasheet is written that the TPS62237 is able to keep the Ton at 100% in order to have Vout = Vin when Vin is close to the desired regulated output. This can help to use more capacity of a single cell Lithium battery.
On my board the current consumption is 87.3mAdc, when Vin = 3.737Vdc, and Vout = 3.329Vdc.
With the theoretical calculation, the Vout should stay at 3.329Vdc even if Vin is as low as 3.411Vdc :
Vin min = Vout max + Iout max * (RDSon max + RL) = 3,329 + 0,0873 * (0,850 + 0,095) = 3,411Vdc
But the measure is different from the theory :
| Vin (batterie) [Vdc] | Vout (3,3Vdc regulated) [Vdc] |
| 4,31 | 3,325 |
| 3,741 | 3,329 |
| 3,64 | 3,329 |
| 3,61 | 3,302 |
| 3,5 | 3,188 |
| 3,314 | 2,997 |
| 3,005 | 2,679 |
| 2,71 | 2,37 |
Vout starts to decrease when Vin is around 3.6Vdc. Is there something wrong ?
I thank you in advance.
Fred
