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    Electronic Components
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    2. Electronic Components
    3. Capacitor
    4. Polymer Aluminum Electrolytic Capacitors
    5. Main applications and examples of use
    6. Wireless charging (rapid charging) usage examples
    Polymer Aluminum Electrolytic Capacitors

    Polymer Aluminum Electrolytic CapacitorsWireless charging (rapid charging) usage examples

    Wireless charging market trends and issues

    Image of Wireless charging usage examples
    Image of Market trends and issues

    More smartphones today are using wireless charging, and so there is an increasing need for rapid charging capable of charging devices quicker.
    However, the larger current required of rapid charging can generate noise.
    High-performance wireless charging is therefore required to suppress noise, make charging more pleasant (low noise, with Tx and Rx communication related to power supply conditions), and allow for reliable voice and data communications.

    Issues with wireless charging that can be resolved with capacitors

    • Noise when charging
    • Unreliable voice/data communications (Tx and Rx communications, etc.)

    Features of Murata's polymer capacitor ECAS series

    Murata's polymer capacitors are solid-state layered film polymer aluminum capacitors (ECAS series).
    They have low noise, low ripple noise and high reliability. Additionally, there is no DC bias characteristic for capacitance and the temperature characteristic is stable.
    This contributes to reducing the number of parts as well as the size of the circuit board area.

    Example of applied circuit

    The ECAS series can be used in circuits such as shown in the figure below.

    Image of Example of applied circuit

    Advantages of using the ECAS series

    Low noise

    The ECAS series uses materials that produce less acoustic noise compared with MLCC, contributing to a reduction in environmental noise.

    Conventional capacitor
    Image 2 of Conventional capacitor
    Image 1 of Conventional capacitor

    Please click "▶bottom" to play the recorded acoustic noise (32 sec).

    For human
    Audible frequency: 20-20kHz
    Dissonant noise: 2k-4kHz
    Image of Superimposed signal data(2kHz) on power delivery is audible frequency.
    ECAS series
    Image 2 of ECAS series
    Image 1 of ECAS series
    V_line Cap Recommendation parts: ECAS

    Low acoustic noise
    Low ESR
    Low profile

    Image of ECAS
    5V/9V/15V/20V
    Depend on USB-PD    		 C1in ECASD31E156M040KA0
    (25V/15uF/40mΩ/1.5mm_t)
    Max 20V C2in ECASD31E226M040KA0
    (25V/22uF/40mΩ/1.5mm_t)
    ECASD41E336M040KA0
    (25V/33uF/40mΩ/2.0mm_t)
    Max 20V
    Depend on App    		 Cout ECAS series
    (25-16V/**uF/**mΩ/1.5mm_t)

    You can also view a video showing the main causes of acoustic noise and ways to counteract them. Be sure to watch it to get an idea though images of phenomena that may be difficult to visualize, such as vibration of circuit boards on which chips are mounted.

    • Causes of acoustic noise: Starts at 1:50 seconds
    • Description of countermeasures: Starts at 2:17 seconds

    Low ripple noise

    The ECAS series with its low ESR characteristics has excellent ripple noise suppression performance.
    Therefore, we can realize stable voice and data communication by removing the noise that is generated in the larger currents of rapid power supply.

    When a tantalum capacitor is used Image of When a tantalum capacitor is used
    When the ECAS series is used Image of When the ECAS series is used

    High reliability

    The ECAS has more stable reliability compared to tantalum capacitors, which contributes to stable set operation.

    Graph of Reliability * Test condition: High temperature load

    Comparison with other capacitors

    Comparison with tantalum capacitors

    Low ESR

    The ECAS series has lower ESR compared to tantalum capacitors, which enables the realization of lower ripple noise.

    Graph of Low ESR

    Application notes

    PDF documents of wireless charging application examples are also available.
    Download the documents below to view the materials.

    Wireless charging application notes (PDF: 0.3 MB)

    Download
    1. Electronic Components
    2. Capacitor
    3. Polymer Aluminum Electrolytic Capacitors
    4. Main applications and examples of use
    1. HOME
    2. Electronic Components
    3. Capacitor
    4. Polymer Aluminum Electrolytic Capacitors
    5. Main applications and examples of use
    6. Wireless charging (rapid charging) usage examples
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