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TMS320F28377S-Q1: Hibernate Wake-up Circuit Advise

Fikret Yildirim
Prodigy 105 points
Part Number: TMS320F28377S-Q1
Other Parts Discussed in Thread: TMS320F28377S

Tool/software:

Hi,

I am currently working on a design that uses the TMS320F28377S microcontroller. Since power consumption is a critical factor in my application, I need to put the system into a low-power state for extended periods. Based on the device datasheet, I found that the HIB (Hibernate) mode significantly reduces power consumption and is well-suited for my use case.

According to the documentation, waking the device from HIB mode requires a brief LOW pulse followed by a HIGH level on the GPIO41 (GPIOHIBWAKE) pin. I would like to implement a hardware circuit that can generate this wake-up signal in a simple, stable, and ultra-low-power manner.

My initial idea is to use a basic RC circuit: when an external HIGH signal is applied, it goes through a series resistor to GPIO41. A 1 µF capacitor is connected between GPIO41 and GND. Upon receiving the HIGH signal, the capacitor slowly charges, keeping GPIO41 LOW for a short period (defined by the RC time constant), and then gradually allowing it to rise to HIGH. This satisfies the HIB wake-up requirement.

While this solution appears simple and functional, I’m uncertain about its long-term stability and performance under varying temperature conditions. I would greatly appreciate it if you could share any recommendations or alternative circuit ideas you might have for achieving a more robust or power-efficient wake-up mechanism.

Thank you in advance for your time and support.
Looking forward to your valuable input.

  • 0
    Prodigy 105 points

    Hi , I was try this circuit on LTspice . Is  enaugh for wake MCU from hibernate mode .

  • 0 in reply to Fikret Yildirim
    TI__Expert 4630 points

    Hello,

    Your initial idea of using a basic RC circuit is a good starting point.

    Here are some alternative ideas and recommendations to consider:

    Use a dedicated wake-up IC: There are specialized ICs designed specifically for wake-up applications. These devices can generate a clean, precise wake-up signal with minimal power consumption.
    Implement a capacitor charging circuit: Instead of using a resistor-capacitor (RC) circuit, you can use a capacitor charging circuit to generate the wake-up signal. This approach can provide a more stable and predictable timing.
    Utilize a timer-based wake-up circuit: Design a circuit that uses a timer to generate the wake-up signal. This can be achieved using a dedicated timer IC or a microcontroller-based solution. This approach can provide a more accurate and reliable timing.
    Optimize the RC circuit: If you still want to use an RC circuit, you can optimize its design to minimize power consumption and maximize stability. Use a smaller capacitor value, a larger resistor value. For capacitor, use Negative-Positive 0PPM/°C (NP0/C0G) capacitors as these have better stability over temperature and across input frequencies than other types of capacitors

  • 0 in reply to Stevan Duraskovic
    Prodigy 105 points

    Hİ,

    As part of my current design, I have followed your recommendation to use NPO/COG capacitors due to their stability and low temperature coefficient characteristics. I have selected capacitors in the range of 10nF to 100nF. I would like to confirm whether this value range is considered optimal for general-purpose timing or filtering applications, or if any adjustments are recommended based on practical experience. Additionally, in your previous suggestions, you mentioned implementing a capacitor charging circuit. I would greatly appreciate it if you could share an example or reference design related to this concept, particularly one that could be applicable for low-power or precision analog applications.

    Thank you in advance for your guidance and support.

  • +1 in reply to Fikret Yildirim
    TI__Expert 4630 points

    Hello,

    You've chosen a good range of capacitor values for general-purpose timing or filtering applications. However, the optimal value depends on the specific requirements of your design, such as the desired time constant, frequency range, and voltage rating.

    For low-power or precision analog applications, a capacitor value between 10nF to 100nF is a good starting point. Here are some general guidelines:

    • For low-frequency applications (e.g., HIB mode wake-up), a higher value capacitor (e.g., 100nF) might be more suitable to provide a longer time constant and a more stable output.
    • For high-frequency applications, a lower value capacitor (e.g., 10nF) might be more suitable to provide a faster response time and a more accurate timing.