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| What DCDC VRegs have a constant current limit feature? Its hard to search for it |
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| Psi:
I'm looking for a little monolithic DCDC VReg chip but I'm having trouble finding an all-in-one IC solution that fits my requirements. Anyone know a chip that has the following specs? - My main requirement, (the one causing issues), is a built-in constant current regulation feature. I want it do CC mode at around 3A with the output going down to a few volts in CC mode. I have found some chips that have CC mode, but they sense current in the ground line. For my application input and output ground must be common. - Built-in switching mosfet - Input 12/24v system, so needs to be spec'ed to run up to 32V - Output regulated to 15V (if Vin high enough) - Step-down (or could be step-up/down) - Ideally automotive rated spec - Price per chip can be high-ish, if needed. $8 each at 100pcs is not out of the question. Any recommendations welcome. |
| daqq:
Could this work? https://www.analog.com/media/en/technical-documentation/data-sheets/3477fd.pdf edit: See page 14 for higher voltage operation. |
| Psi:
--- Quote from: daqq on November 02, 2020, 10:49:17 am ---Could this work? https://www.analog.com/media/en/technical-documentation/data-sheets/3477fd.pdf edit: See page 14 for higher voltage operation. --- End quote --- Sadly the circuit on page 14 that allows higher voltage operation removes the common ground between input and output. |
| tom66:
You could implement this function by driving the FB line of many conventional DC-DC converters with an external op-amp. That op-amp could use a high side current sensor (e.g. Zetex ZXCT10xx) to monitor output current. If you use a diode to OR your feedback signal, then you could have CV/CC operation. I appreciate this is more complex than an off-the-shelf solution but it may end up giving you the most availability. |
| Psi:
--- Quote from: tom66 on November 02, 2020, 10:59:18 am ---You could implement this function by driving the FB line of many conventional DC-DC converters with an external op-amp. That op-amp could use a high side current sensor (e.g. Zetex ZXCT10xx) to monitor output current. If you use a diode to OR your feedback signal, then you could have CV/CC operation. I appreciate this is more complex than an off-the-shelf solution but it may end up giving you the most availability. --- End quote --- yes, this is my fallback option. I just really want something that's ready to go and am willing to pay a bit more for it. For this project being able to take the example schematic from the datasheet and know it will work first time will be a big time saver. It will require less testing and validation. |
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