How does STEVAL-ISV020V1 provide LDOs when the PV panel hasn't sunlight?

RCarv.3 · ‎2021-05-24

I am working with STEVAL-ISV020V1 and I have a PV pannel and a battery connected with 3.3 V close to the maximum capacity.

When we don't have power supply on PV panel, shouldn't the battery voltage supply the system?

for example, shouldn't it have 1.8V and 3.3V in LDOs output as long as it has battery power?

Thanks!

Rui

Peter BENSCH · ‎2021-05-25

The LDOs are supplied from the voltage at STORE, which is only connected to the battery when the internal battery switch is closed, indicated by /BATT_CONN = low (see description of SPV1050). In addition to that the LDOs need to be enabled using LDO1_EN and/or LDO2_EN.

Regards

/Peter

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RCarv.3 · ‎2021-05-25

Hi,

But when I haven't sunlight and LDOs enabled there is only voltage at STORE. In same time battery have near of maximum capacity.

My system have really voltage at STORE and LDOs (less at 1.8V and 3.3V) too when there are sunlight other case don't have.

So it is possible config my system to supply STORE and LDOs when sunlight there isn't?

On datasheet of board I don't understand if system can work without sunlight while has battery voltage.

Regards,

Rui Carvalho

Peter BENSCH · ‎2021-05-26

Please check the EOC voltage and the status of /BATT_CONN.

What type of battery is connected to the kit (voltage, capacity)?

Regards

/Peter

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RCarv.3 · ‎2021-05-26

WIth one and two LDOs enable EOC is -0.48V and BATT_CONN is -0,10V.

With only one LDO enable EOC is -0,68V and BATT_CONN is -0,14V.

So I'm enable LDO's with PWM and if we enable one and two LDO and we can measure one positive voltage and other in opposite.

I think the VEOC it is very small but i don't know why....

For this results I haven't any input on PV IN.

I have 3 (AA900mAh 1.2V ni-mh) rechargeable battery in serie.

Regards,

Rui

Peter BENSCH · ‎2021-05-27

Shell I read your voltage levels at EOC as negative voltages or do you mean positive ones?

Just to be sure: are you measuring with reference to GND?

I forgot to ask for the voltage at STORE for your measurements you mentioned above (VBATT+ should be of the same value)?

What else is connected, e.g. to CN4 (EXT_SUP)?

BTW: the schematic still contains a typo and incorrectly designates TP6 as UVP, which should be read as EOC.

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RCarv.3 · ‎2021-05-27

Oh sorry, I meausered wrong.

So with two enables LDOs at same time on EOC measure is 0.49V and STORE 2V.

Should EOC be higher for instance close of STORE value?

On CN4 connector have connect a lamp leds.

Yes i had already seen that TP6 is a EOC, thanks.

Regards,

Rui