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Here, this Boost converter, says that it can boost the input voltage from 2.5 V to 10 V.

My input is from a 7.4 V, 7.5 Ah battery. Output is 9 V. The maximum load current is 3 A.

Ideally, for my OVP feature to work, I need to keep the resistor divider such that the OVP threshold value is more than 9 V, right? But according to the electrical characteristics table, the maximum value of OVP is 6.3 V.

Does it makes sense, or am I missing something here?

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  • \$\begingroup\$ Yes, so make sure your divided value at 9+ V is 6.3 at the OVP pin? \$\endgroup\$
    – winny
    Commented Apr 3, 2023 at 10:13
  • \$\begingroup\$ @winny, could you please explain a little more? If my output voltage is higher than the 6.3V, it doesn't make sense to have the OVP feature, right? How will OVP work then if its maximum value is only 6.3V, when my output is 9V? \$\endgroup\$
    – user220456
    Commented Apr 3, 2023 at 10:18
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    \$\begingroup\$ Because your voltage divider will divide it down, effectively raising the OVP to something higher than 6.3 V. \$\endgroup\$
    – winny
    Commented Apr 3, 2023 at 10:29
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    \$\begingroup\$ Refer to the OVP section on page 8 of the datasheet, it explains it quite clearly. \$\endgroup\$
    – Finbarr
    Commented Apr 3, 2023 at 11:16

2 Answers 2

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Ideally, for my OVP feature to work, I need to keep the resistor divider such that the OVP threshold value is more than 9V, right? But according to the electrical characteristics table, the maximum value of OVP is 6.3V.

The OVP threshold is typically 5.6 volts and might be as high as 6.3 volts or, as low as 5.25 volts. So, to prevent the normally expected 9 volt output tripping the OVP (a safety mechanism to protect the output and load), you need to ensure that the resistive divider from the 9 volt output to the OVP input is just below 5.25 volts: -

enter image description here

So, if the output rose to (say) 9.05 volts, the OVP would trip. However, because you cannot be sure of the OVP threshold, the output might have to rise to 10.8 volts. So, you have to decide whether 10.8 volts on the output is too much and, if it is, you'll have to use select-on-test resistors in the resistive divider to ensure the OVP trip comes in at slightly above 9.0 volts. From the data sheet: -

enter image description here

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    \$\begingroup\$ Thank you very much for the answer. Let me just check on this and come back. \$\endgroup\$
    – user220456
    Commented Apr 4, 2023 at 5:51
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Here you go. The OVP divider is no different from the FB divider, just a higher setpoint:

schematic

simulate this circuit – Schematic created using CircuitLab

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  • \$\begingroup\$ Thank you for your answer. I think the datasheet isn't very clear on the OVP pin as much as the FB pin, right? \$\endgroup\$
    – user220456
    Commented Apr 4, 2023 at 5:51
  • \$\begingroup\$ @Newbie What struck me was the extremely wide tolerance on the OVP setpoint in the datasheet. \$\endgroup\$
    – winny
    Commented Apr 4, 2023 at 6:39
  • \$\begingroup\$ Yes, I feel the datasheet is quite misleading on this point. \$\endgroup\$
    – user220456
    Commented Apr 4, 2023 at 7:20

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