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TPS92830-Q1: Enable/Disable switching

Vaibhav Khatri
Prodigy 160 points
Part Number: TPS92830-Q1

Tool/software:

Hello,

I am planning to design a headlamp with TPS92830-Q1. I do not intend to use the Analog/PWM dimming functionality. I want to use each of the three channels individually and enable/disable them through a 12V signal.

As per my interpretation of the datasheet, I don't see any individual Enable/disable pin for the three channels. What I have seen in the datasheet is that, you can achieve 100% duty-cycle if you tie FD pin to VCC. I intend to use 100% duty-cycle.

I was wondering if PWMx pins can be tied to VCC through a MOSFET so that individual channels can be turned ON/OFF.

Is it possible to use PWMx pins for Enable/disable functionality?

Thanks

Vaibhav Khatri

  • 0
    TI__Prodigy 480 points

    Hello Vaibhav,

    Your interpretation of the data sheet is correct. The PWMx pins will directly enable and disable the output channel. You can use a MOSFET to drive these inputs but they might be unnecessary if the signal can reach above the maximum value for V_IH(PWMx) and stay below the recommended PWMx maximum.

    If you have any other questions, please let me know.

    Kind Regards,

    Nicholas Alexander

  • 0 in reply to Nicholas Alexander
    Prodigy 160 points

    Hi Nicholas,

    As mentioned in the datasheet on page 7, VIH(PWMx) must not exceed 1.248V, so if I provide a voltage higher than that would it not damage the PWMx pins?

    It is also mentioned of page 6 PWMx inputs can sustain input voltages upto VIN.

    So can I provide any voltage higher than 1.248V on pins PWMx?

    Thanks,

    Vaibhav Khatri

  • +1 in reply to Vaibhav Khatri
    TI__Prodigy 480 points

    Hello Vaibhav,

    VIH(PWMx) is the voltage level when the internal logic for PWMx will go from low to high. You can exceed this voltage. This value is given because the PWMx input pins have an internal Schmitt Trigger.

    The recommended operating conditions, shown below, is the value that the PWM pins can handle before risking damage to the device.

    In other words, a logic low will be a value from 0 to VIL(PWMx) and a logic high will be a value from VIH(PWMx) to V(IN) for each PWMx input.

    Best,

    Nicholas Alexander