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TPL9202 Relay Driver

Other Parts Discussed in Thread: TPL9202

Hello,

I am planning to use two TPL9202's to drive HE751A1200 relays from Hamlin and EV-2M-12 Solenoid Valves from Clippard. I am interfacing the TPL9202 to 5V SPI bus that have individual Chip Selects. I have connected the OUTn pins to the respective Relays and Solenoids. Do I need to use any protection diodes on the output ?

The Relays would consume about 0.15 W and the Solenoids would consume about 0.67 W. I have connected the Exposed PAD to GND plane on my PCB.

A Snapshot of the schematic is as below. I would request you to kindly review the same.

 

 

Thanks and Regards,

Naveen

  • Hello Naveen,

    Add a small capacitor between the TPL9202 5V output and ground, 0.01uF or 0.1uF will suffice.
    The BO (brownout input) must be greater than 1.3V; it can be tied to ~RST pin.

    If it is possible to disconnect the inductive load while it is energized, then more protection is needed.
    Hot plugging or unplugging an inductive load creates a electric spark at the connector and the TPL9202 may not survive.

    There are two protection methods.
    1) Connect a standard general purpose diode on the coil such that it stays on the coil during the hot plug event. (prevents high voltage spike)
    2) Connect a Schottky diode (fast response) from TPL9202 output to coil supply voltage (12V). (redirects high voltage spike.)

    Regards,
    Ron Michallick.