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
@copilot can you combine three modules comprises of - 7.4 dc battery charging module, battery BMS, booster module similar to XL6009 with power button circuit
This project involves designing a DC-DC buck converter circuit to efficiently step down a 12V input voltage to a stable 5V output voltage. The converter is suitable for various electronic applications requiring 5V DC supply from a 12V source.
Key Components:
IC1 (TPS5430DDA): This is a step-down switching regulator capable of providing a 5V output from a 12V input. It features low power consumption, high efficiency, and robust protection features. The pin configuration includes bootstrapping, voltage sensing, enable, ground, input, and phase pins.
U1 (S-LMBR340FT1G): A Schottky Barrier Rectifier, which offers fast switching and low forward voltage drop, used to improve the overall efficiency of the converter.
Inductor L1: 10 µH inductor for energy storage and smooth current transitions during the switching process.
Capacitors:
C1: 100µF output capacitor for filtering voltage ripples.
C2: 47µF input capacitor to stabilize input voltage and minimize ripple.
@copilot
Create a step-down buck converter schematics based on IC1 (TPS5430DDA).
Input range: 5.5-24v
output: constant 5V
Output current: 3A
Consider standard values for passive components. Provide instructions for the design and the connections necessary for this requirement.
What should I consider regarding inductor selection, capacitor requirements, and heat dissipation?
Do I need any additional circuitry for protection or stability?
To design a step-down buck converter using the TPS5430DDA, we'll need to select appropriate passive components such as an inductor, capacitors, and possibly some additional components for stability and protection. Here's a breakdown of the design considerations and the connections needed:
Schematic Connections
Inductor (L1) Selection:
Value: Typically around 10-22 µH for a buck converter with this specification. The exact value can be chosen based on ripple current and efficiency needs.
Values for R1 and R2: Use the formula $ V_{\text{OUT}} = V_{\text{REF}} \times (1 + \frac{R1}{R2}) $ where $ V_{\text{REF}} $ is typically 1.221V for TPS5430DDA.
Calculate R1 and R2 for a 5V output. You might use standard values like R1 = 33kΩ and R2 = 10kΩ.
Connect R1 between IC1:VSENSE and the output node.
If you want to have controller enable/disable functionality driven by an external circuit or microcontroller, connect IC1:EN accordingly. If always on, connect it to IC1:VIN or leave it open, depending on your specific startup sequencing requirements.
Considerations:
Inductor Selection: Choose an inductor with a current rating above 3A with low DC resistance to minimize losses. It should handle the peak current without saturation.
Capacitor Requirements: Use low-ESR capacitors to minimize output voltage ripple and improve efficiency.
Heat Dissipation: Use adequate copper area on the PCB and thermal vias under the IC to dissipate heat. The TPS5430DDA features an exposed thermal pad for this purpose.
Protection and Stability: Consider adding input and output capacitors, Snubber circuits on the switch node to dampen voltage spikes, and diode clamping for additional protection.
Additional Circuitry for Protection:
Input Fuse: To protect against overcurrent conditions.
TVS Diode: For input transient voltage suppression.
Overcurrent Protection: Can be integrated into the design or calculated based on the chosen components’ ratings.
Transient Voltage Suppressor (TVS) diodes are used to protect sensitive electronics from voltage spikes induced by events such as lightning strikes, power grid switching, and electro-static discharge (ESD). Below is a general guide on selecting and implementing a TVS diode for input transient voltage suppression:
Selecting a TVS Diode
Stand-off Voltage (V_WM):
Choose a diode with a stand-off voltage slightly above your maximum input voltage to prevent unnecessary clamping during normal operation.
Since your input is 5.5-24V, a TVS with a stand-off voltage around 26-30V could be suitable.
Clamping Voltage (V_C):
This is the voltage the TVS diode will clamp during a transient. It should be low enough to protect your circuit but above the normal operating voltage.
Peak Pulse Current (I_PP):
Ensure the TVS diode can handle the expected peak pulse current of your application, which depends on the anticipated level of transients.
Power Dissipation:
Look for a TVS diode with adequate power dissipation capability to handle the energy of the surge.
Package Type:
Choose a package type that matches your PCB layout and space constraints.
Implementing TVS Diode
Placement:
Place the TVS diode as close to the power input connector as possible. This minimizes the loop area to reduce the inductance and improve the response time to transients.
Connection:
Connect the cathode of the TVS diode to the positive input line (Vin).
Connect the anode to ground.
Example Components
Here are a few examples of TVS diodes that might match your application needs:
SMBJ24A:
Stand-off Voltage: 24V
Clamping Voltage: Around 38.9V at 1A
Peak Pulse Current: 6.7A
Package: DO-214AA (SMB)
SMAJ26A:
Stand-off Voltage: 26V
Clamping Voltage: Around 42.1V at 1A
Peak Pulse Current: 5.8A
Package: DO-214AC (SMA)
P6KE24A:
Stand-off Voltage: 24V
Clamping Voltage: 33.2V
Peak Pulse Current: 22A
Package: DO-15
Additional Considerations
Reverse Standoff Voltage should exceed the working DC voltage.
Ensure the clamping voltage is below the maximum voltage rating of components in your circuit to safely absorb transients.
Use TVS diodes with low leakage current to minimize their effect in normal operations.
Would you like further details on any specific feature, or assistance with selecting a particular TVS part?
Let's review your schematic setup for the step-down buck converter using the TPS5430DDA to ensure it meets the 5V, 3A output requirement. Then, I'll provide suggestions and calculate the output voltage based on the resistor divider network:
Review of Schematic Connections:
Inductor (L1):
Ensure that the inductor is connected between IC1:PH and the output node.
Make sure the inductor can handle at least 3A with some margin to prevent saturation and reduce losses (~10-22µH).
IC1:VSENSE should connect to the junction of the resistor divider R1 & R2.
R1 and R2 are selected to set V_OUT using the formula $ V_{\text{OUT}} = V_{\text{REF}} \times \left(1 + \frac{R1}{R2}\right) $, where $ V_{\text{REF}} = 1.221 , \text{V} $ for this IC.
With R1 = 33kΩ and R2 = 10kΩ:
VOUT=1.221×(1+10k33k)≈5.007V (close to the desired 5V).
Bootstrapping Capacitor (C3):
Connect IC1:BOOT to IC1:PH with a 0.01 µF capacitor.
Enable Pin (EN):
Connect IC1:EN appropriately based on the intended power-on sequence.
Suggestions:
Check Inductor and Capacitor Ratings: Ensure they are rated for the necessary current and voltage.
Thermal Management: Adequately size the PCB copper areas for thermal dissipation; consider thermal vias under the IC.
Noise Considerations: Keep high-frequency switching paths short and wide to minimize electromagnetic interference (EMI).
Calculation of Output Voltage:
Using the resistor divider formula provided:
The calculated V_OUT is approximately 5.007V based on the chosen resistor values (R1 = 33kΩ and R2 = 10kΩ).
Conclusion:
These connections and settings should provide a stable 5V output for your requirements. Ensure that all selected component specifications meet or exceed the design conditions, especially focusing on thermal and transient protections.
If you have any further questions or need additional modifications, feel free to ask!
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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.
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