Power net portal is a special schematic object used to define a power or ground net. Power ports allow you to conveniently indicate a power net at any location in the design. Power nets of the same designator automatically connect throughout your design #portal #power
A generic fixed inductor for rapid developing circuit topology. *You can now change the footprint and 3D model at the top level anytime you want. This is the power of #generics
Yes, protecting a USB port is crucial for the longevity and reliability of both the device containing the USB port and the devices connected to it. Based on your project, which already includes some protection elements, there are several strategies to enhance USB port protection further:
ESD Protection: Your design already incorporates an ESD protection IC (U3: NUF2221W1T2G by onsemi), which is a great start. ESD protection devices help to protect sensitive electronic components from electrostatic discharges during handling or in the event of a static shock.
Overcurrent Protection: Implementing a fuse or a Positive Temperature Coefficient (PTC) resistor can protect the USB port from current overloads. A resettable fuse (PTC) is beneficial as it returns to normal operation once the overcurrent condition ceases.
Connect a PTC fuse in series with J1:VBUS.
Overvoltage Protection: Overvoltage can be detrimental to devices connected to the USB port. A Transient Voltage Suppression (TVS) diode can be added to protect against voltage spikes.
Connect a TVS diode across the VBUS and GND pins of the USB receptacle (J1) to clamp voltage spikes to safe levels. Make sure the TVS diode's working voltage is slightly above 5V and can handle the transient power.
Reverse Voltage Protection: To prevent damage from reverse voltage connection, a Schottky diode can be placed in series with the VBUS line to block negative voltages.
Connect a Schottky diode in series with J1:VBUS pin, ensuring the cathode of the diode faces the internal circuitry, to provide reverse polarity protection.
Data Line Protection: While ESD protection on data lines is covered by U3, considering additional filtering or protection components can further improve resilience. For high-speed data lines, ensure that any added components do not significantly degrade the signal integrity.
Quality USB Connectors: Using high-quality USB connectors with better mechanical construction and materials can also enhance durability and provide better shielding against electromagnetic interference (EMI).
Implementing a Self-Powered Design: For devices that can afford it, designing the USB interface to be self-powered (rather than bus-powered) can offer an additional layer of protection from issues related to the host's power stability.
Remember, the key to effective protection is not just about adding components but ensuring they are correctly rated and properly integrated into your design. Always verify with simulations or calculations where possible, and consult datasheets or application notes for specific components to make informed decisions.
10mo
@copilot What is CC1 and CC2 in this schematic means
In the context of your schematic, CC1 and CC2 refer to the Configuration Channel pins of the USB-C connector. These pins play a crucial role in the USB Type-C specification for detecting cable orientation and managing power delivery and data roles between devices. Here's a breakdown of their functions:
CC1 and CC2: Each USB-C connector has two Configuration Channel pins, labeled CC1 and CC2. The presence of two such pins allows the USB-C cable to be reversible. When a USB-C cable is connected, the orientation (which side is up) is determined by which of these pins makes contact. This flexibility is one of the key improvements of USB-C over previous USB connectors.
These pins are used for several purposes:
Determining the orientation of the cable connected to the port.
Initiating the Power Delivery (PD) protocol if the devices on either end support it. This can negotiate higher power levels than standard USB connections, allowing for fast charging and powering of larger devices.
Identifying the attached device or cable type, which helps in determining the data roles (host or device) and the available modes of operation (for example, DisplayPort, Thunderbolt, or USB data).
In your project:
CC1 is connected through a resistor (labelled R1), likely for cable orientation detection or as part of a USB Power Delivery communication circuit.
CC2 is similarly used, with a resistor (labelled R2), indicating a mirrored setup to support either orientation of the USB-C plug.
These connections suggest your design supports basic USB-C functionality with considerations for orientation detection and possibly power negotiation, depending on the connected devices and cable.
VDD is a label typically used to denote the positive supply voltage in a circuit. The terminology comes from MOSFET terminology, where "V" stands for voltage, "D" for Drain, and the second "D" indicates that this is the voltage at the Drain with respect to the substrate.
In your project, VDD is likely the power supply for the EMI Filter (U3) and the LDO Voltage Regulator (U2). It's also connected to capacitor C2. The exact voltage level would depend on the specifications of these components and the requirements of your design.
The typical value for VDD can vary greatly depending on the specific IC and the technology used. However, here are some common values:
For many modern low-power ICs, such as those used in battery-powered devices, a common VDD value is 1.8V.
For many CMOS logic ICs, common VDD values are 3.3V and 5V.
For some older or high-power ICs, VDD might be as high as 12V, 15V, or even 24V.
However, the exact value you should use for VDD in your circuit depends on the specifications of the specific components you're using. For instance, the LDO regulator in your circuit (ME6206A33XG) outputs a fixed 3.3V, suggesting that any connected components are likely operating at this voltage. Always refer to the datasheets for your components to determine the appropriate supply voltage.
In the context of your circuit, with a USB-C connection, VDD would typically be the power supply rail for digital logic, which would usually be at 3.3V or 5V.
However, since you have an LDO regulator (ME6206A33XG) in your circuit that outputs a fixed 3.3V, the VDD in this circuit would be 3.3V. This is assuming that the USB-C power supply is providing a voltage higher than 3.3V (such as the standard 5V from a USB power source), which is then being regulated down to 3.3V by the LDO for use in your circuit.
Please confirm this information from the datasheet or from your circuit design requirements.
In this circuit, VDD is the unregulated voltage input from the USB VBUS pin, while 3V3 is the regulated 3.3V output from the LDO regulator (U2: ME6206A33XG).
They are separated in the netlist because they represent different voltages in the circuit.
VDD is connected to the input of the LDO regulator and the EMI Filter VDD pin.
3V3 is the output from the LDO regulator which provides a stable 3.3V power supply to other components in the system.
The separation of these nets helps ensure that the higher, unregulated voltage from VDD doesn't interfere with the components that require a stable 3.3V supply, and it allows for better tracking of power flow and fault isolation in the circuit.
Hey, I'm copilot! I can help you with all kinds of stuff in your project. Reach me at any time by tagging me on comments or in the chat with my handle, @copilot.
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Passive Components
Resistor Power Rating
Beta
Checks that the power traveling across a given resistor is under its rating with 50% headroom.