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Thread: Dynamic Braking Control with IFX007T

  1. #1
    New Member New Member jaygeeracing is on a distinguished road
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    Dynamic Braking Control with IFX007T

    I currently have a dynamic braking circuit for a brushed DC motor that has the brake current (and brake strength) controlled by a PWM signal applied to the low side FET. The high side is shut off while braking.

    1. Can the IFX007T be used to perform the same function by holding the IN pin low and applying the PWM signal to the INH pin?

    2. What protections are sacrificed when operating in this mode?

    3. Output timing when coming out of sleep mode isn't specified. With a 1KHz PWM signal applied to the INH pin, is the IFX007T fast enough to vary the output pulse width from 5% to 95%?
    Last edited by jaygeeracing; Nov 7th, 2020 at 11:43 AM. Reason: typo correction

  2. #2

    Infineon Employee
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    Jing.N is on a distinguished road
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    Please see my comments below:
    1. Can the IFX007T be used to perform the same function by holding the IN pin low and applying the PWM signal to the INH pin?
    Yes, it can be used to perform this function by holding IN pin to LOW and applying PWM signal at INH pin.

    2. What protections are sacrificed when operating in this mode?
    When INH is set to LOW, the fault signal won't present at IS pin and the device will enter stand-by mode. Please find the details in the truth table:
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    3. Output timing when coming out of sleep mode isn't specified. With a 1KHz PWM signal applied to the INH pin, is the IFX007T fast enough to vary the output pulse width from 5% to 95%?
    We don't guarantee this duty cycle in - out transfer function since we don't specify this parameter in the datasheet. But you can look into the application note (chapter 5.6), and use figure 53 as a reference. Compare to the timing coming out of stand by mode, the delay on/off time has more significant influence on the duty cycle. This figure shows that the delay on/off time (duty cycle variations) becomes smaller with lower slew rate resistance:
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    In your case, you set IN to LOW and switch on/off LS by applying PWM at INH. It means you don't need to consider the deadtime generation and the timing to switch off HS. Therefore I would assume that the duty cycle transfer function will be better.
    The views expressed here are my personal opinions, have not been reviewed or authorized by Infineon and do not necessarily represent the views of Infineon.

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