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Driving relays..is this acceptable?

colporteur

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Is this acceptable? Are there any downsides?

I am looking to drive three 12V relays. My plan is to replace the single relay in the MOSET circuit with the three relays.

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  • The circuit looks good. As the others mentioned, put a snubber diode on each relay. Ensure the gate voltage provided by the resistor divider is sufficient to saturate the FET at the current it needs to drive the relays. (The gate threshold voltage is not enough) R1 shouldn't be too high a resistance because the gate capacitance will slow down turn-on and cause more power to be dissipated in the FET. R1 shouldn't be too low either to protect the VDRIVE from high current while charging the gate capacitance. If there is a lot of drain current, calculate if a heatsink is needed.

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  • The circuit looks good. As the others mentioned, put a snubber diode on each relay. Ensure the gate voltage provided by the resistor divider is sufficient to saturate the FET at the current it needs to drive the relays. (The gate threshold voltage is not enough) R1 shouldn't be too high a resistance because the gate capacitance will slow down turn-on and cause more power to be dissipated in the FET. R1 shouldn't be too low either to protect the VDRIVE from high current while charging the gate capacitance. If there is a lot of drain current, calculate if a heatsink is needed.

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