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i want to protect At mega 328p from surge current so i am using one lm358 voltag...
1y
A Transient Voltage Suppression (TVS) diode is a device designed to protect electronic circuits from transient voltage spikes, such as those caused by lightning, electrostatic discharge (ESD), or inductive switching. Here are some key points about TVS diodes:
- Operation: A TVS diode remains in a non-conductive state under normal operating conditions. However, when a transient voltage spike exceeds a certain threshold, it becomes conductive, clamping the voltage to a safe level and diverting the excess energy away from the protected components.
- Types:
- Unidirectional: Used for circuits with only one polarity of voltage.
- Bidirectional: Used for AC circuits or DC circuits where the transient could be of either polarity.
- Applications: Often found in communication lines, power supplies, and any other sensitive electronic circuits that need protection from transient voltages.
- Symbol: The symbol for a TVS diode is similar to that of a Zener diode but may have additional markings to indicate its transient suppression capabilities.
TVS diodes are crucial for maintaining the reliability and longevity of electronic systems by protecting them from potentially damaging spikes in voltage.
If you have a particular TVS diode or application in mind, feel free to share more details for targeted advice!
1y
What is tvs diode
1y
@copilot i want to protect At mega 328p from surge current so i am using one lm358 voltage regulator to get constant voltage from 12v to 5v and then i am using this 5 v as a input in buffer of lm358 opamp and get the voltage of 4.99 so according to datasheet of atmega its min requirement of current is srounf 0.5 amp while in this set up i am getting the 0.25 amp in input of power supply of at mega so is it good or i should increase the input current will atmega fail to operate at high operations. It is done to protect atmega from pulse current to protect it is there any different aproach . And also what to do to protect it from reverse current
1y
First, let's clarify a few things about your design, then we can discuss protection mechanisms.
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Voltage Regulation: You're using the LM358 op-amp as a buffer, but I think you might be confusing it with a voltage regulator. The LM358 isn't typically used for voltage regulation. For direct voltage regulation from 12V to 5V, you'd typically use an actual voltage regulator like the LM7805 or a switching regulator like the LM2596.
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Current Requirements: The ATmega328P typically requires around 0.5A (500mA) for stable operation. If you are only providing 0.25A (250mA), the microcontroller might not operate reliably under full load or when all peripherals are being used.
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Surge and Pulse Protection:
- Decoupling Capacitors: Use decoupling capacitors close to the ATmega328P’s power pins. Typically, a 0.1μF ceramic capacitor and a 10μF electrolytic capacitor.
- Transient Voltage Suppression (TVS Diode): Use a TVS diode like (PESD5V0S1UL) on the input to clamp high voltage spikes.
- Series Inductor: Add an inductor in series with the power line to filter out high-frequency interference.
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Reverse Current Protection:
- Use a Schottky diode like the 1N5819 in series with the power supply line to prevent reverse current.
- Alternatively, use a P-channel MOSFET with the correct orientation in the power line as a reverse polarity protection switch.
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Improved Voltage Regulation Setup: Consider a more suitable voltage regulation setup:
- 12V to 5V Regulator: Instead of the LM358, use a proper voltage regulator: LM7805.
- Voltage Protection: Include a PESD5V0S1UL TVS diode and proper decoupling capacitors.
- Reverse Protection: Add a 1N5819 diode.
- Regulation: 12V input to LM7805 outputting 5V.
- Reverse Polarity Protection: 1N5819 diode in series with the 12V input.
- Decoupling: 0.1μF and 10μF capacitors across 5V outputs.
- Surge Protection: PESD5V0S1UL TVS diode across the 5V output.
- Power Input Circuit:
- Connect 12V input to 1N5819 Anode.
- Connect 1N5819 Cathode to LM7805 Input.
- LM7805 Output connects to ATmega328P Vcc pin.
- TVS diode PESD5V0S1UL across the 5V output.
- Place a 0.1μF capacitor close to the ATmega328P Vcc and GND pins.
- Place a 10μF electrolytic capacitor close to the LM7805 output.
Would you like a more detailed schematic? If so, I can help to draw it up in Flux.
1y
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piyush0
copilot
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Reverse Current Protection:
- Use a Schottky diode like 1N5819 in series with the input of the L7805 to prevent reverse current. Schottky diodes have a low forward voltage drop and fast switching.
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Spike Voltage Protection:
- Use transient voltage suppression (TVS) diodes like P6KE6.8A across the power supply input to clamp any spike voltages and protect the circuit.
- Additional capacitors can help filter out high-frequency noise: a 100nF ceramic capacitor close to the ATmega328P and a larger electrolytic capacitor, e.g., 220uF, at the input side of the L7805.
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Current Spikes Protection:
- Use a capacitor at the output of the L7805 to smooth out any current spikes. Typically, a combination of a 100nF ceramic capacitor and a 10uF or higher electrolytic capacitor near the microcontroller can help.
Schematic Connections-
Place D1 (1N5819) in series with the input of the U1(L7805):
- Connect D1:Anode to the power supply input.
- Connect D1:Cathode to U1:VIN.
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Place TVS1 (P6KE6.8A) across the power supply input:
- Connect TVS1:Anode to ground.
- Connect TVS1:Cathode to the power supply input.
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Place a 220uF electrolytic capacitor (C1) across U1:VIN and ground:
- Connect C1:Positive to U1:VIN.
- Connect C1:Negative to ground.
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Place capacitors at the output of U1:
- Connect C2:Positive (10uF electrolytic) to U1:VOUT and C2:Negative to ground.
- Connect C3:Positive (100nF ceramic) to U1:VOUT and C3:Negative to ground.
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Connect U1:VOUT to the Vcc pin of the ATmega328P.
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Place an additional C4 (100nF ceramic capacitor) between Vcc and ground near the ATmega328P for decoupling.
Complete Connections List