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Dow to designt an power supply circuit for that esp32?
quaeke

quaeke

@copilot Dow to designt an power supply circuit for that esp32?
2y

copilot

Designing a power supply circuit for the ESP32-WROOM-32 module involves providing a stable power source that matches the module's requirements. The ESP32 operates at 3.3V, and it's crucial to ensure that the power supply can deliver a sufficient current, typically around 500mA, to accommodate bursts during WiFi transmissions or when driving peripherals.
Here's a basic approach to designing a power supply circuit for the ESP32-WROOM-32:
Components Needed:
  1. Voltage Regulator (U2): An LM1117-3.3 or similar, which can output 3.3V at up to 800mA, enough to power the ESP32 and some additional components.
  2. Capacitors:
    • C1 (Input Capacitor): 10 µF, electrolytic, for input decoupling.
    • C2 (Output Capacitor): 10 µF, electrolytic, for output stabilization.
    • C3, C4 (Bypass Capacitors): 0.1 µF, ceramic, for noise reduction on the power supply lines.
  3. Optional: Additional filtering or protection components like ferrite beads or a TVS diode for protecting against voltage spikes.
Design Steps:
  1. Select a Power Source:
    • Can be a USB power supply (5V), a battery pack, or another regulated power source.
  2. Connect the Voltage Regulator:
    • Input: Connect the power source (+) to U2:Vin (Pin of your voltage regulator, exact naming depends on the specific regulator datasheet).
    • Ground: Connect the power source (-) to U2:GND and ESP32-WROOM-32:GND (Pins 1, 15, 38, 39).
  3. Add Capacitors:
    • Input Capacitor (C1): Connect one side to U2:Vin and the other side to GND.
    • Output Capacitor (C2): Connect one side to U2:Vout and the other side to GND.
    • Bypass Capacitors (C3, C4): Connect C3 near the ESP32-WROOM-32:VDD (Pin 2) and another near any peripherals you are powering. Connect one side to the 3.3V supply line and the other to GND.
  4. Power to ESP32:
    • Connect U2:Vout to ESP32-WROOM-32:VDD (Pin 2).
Connection Summary:
  • Connect U2:Vin to your power source (+).
  • Connect U2:Vout to ESP32-WROOM-32:VDD (Pin 2), C2:1, and C3:1.
  • Connect all GNDs together: ESP32-WROOM-32:GND (Pins 1, 15, 38, 39), C1:2, C2:2, C3:2, C4:2, and your power source (-).
Assumptions Made:
  • Your power source is between 4.5V and 12V, suitable for the LM1117-3.3 regulator. If it's higher, consider a regulator that supports a higher input voltage or adds a step-down module before the LM1117.
  • The ESP32 module's consumption spikes do not exceed the regulator's maximum output current.
This setup should give you a stable 3.3V power supply for the ESP32. Remember, it's crucial to check the recommended operating conditions from the ESP32 datasheet and adjust component values accordingly, especially if you plan to attach more peripherals that draw significant power.
2y
quaeke

quaeke

C1 - shuould it be eletrolyt? I need small smd parts.
2y

copilot

For a compact and surface-mount design, you can opt for ceramic capacitors instead of electrolytic. Ceramic capacitors are widely used in SMD (Surface-Mount Device) applications due to their small size and reliability. They also have better frequency characteristics and stability than electrolytic capacitors.
Given the requirements, you could use a ceramic capacitor for C1 with the same capacitance value. Here's a revised approach:
Revised Component for C1:
  • C1 (Input Capacitor): Use a 10 µF, ceramic capacitor with an appropriate voltage rating (at least 1.5x the input voltage for safety). Be mindful of the capacitor's voltage rating, especially if your input voltage approaches or exceeds the common 6.3V or 10V ratings of many SMD ceramic capacitors.
Adjusted Design Steps:
  1. Capacitors: Replace the electrolytic capacitor suggestion with ceramic capacitors for both input and output stabilization.
    • C1 (Input Capacitor): Choose a 10 µF, X5R or X7R dielectric ceramic capacitor for better performance across temperature ranges. Connect one side to U2:Vin (the input pin of LM1117-3.3) and the other side to GND.
    • C2 (Output Capacitor): Similarly, use a 10 µF ceramic capacitor. Although the LM1117 datasheet might recommend an electrolytic capacitor for stability, modern ceramic capacitors, especially those with X5R or X7R dielectric, are typically sufficient for such low-dropout (LDO) applications.
Connection Summary with SMD Recommendations:
  • U2:Vin to Power source (+).
  • U2:Vout to ESP32-WROOM-32:VDD (Pin 2), and one side of C2 (with the other side to GND).
  • C1: Connect one side to U2:Vin and the other side to GND.
  • All GNDs should be connected together: ESP32-WROOM-32:GND (Pins 1, 15, 38, 39), one side of C1, one side of C2, and your power source (-).
By opting for ceramic capacitors, you can achieve a smaller, more reliable SMD-based design. Remember to check the soldering recommendations for the SMD capacitors you select, as larger capacitance values in smaller packages may require careful soldering to manage mechanical stress.
2y
quaeke

quaeke

LM1117-3.3 ist not suituble for lipo based project. could you recommend an alternative?
2y

copilot

For a LiPo (Lithium Polymer) battery-based project, it's important to select a voltage regulator that can efficiently handle the typical voltage range of a LiPo battery, which is usually between 3.7V (discharged) and 4.2V (fully charged), and provide a stable output voltage of 3.3V for the ESP32. The LM1117-3.3, being a low-dropout regulator, might not be the most efficient choice given its dropout voltage, especially when the LiPo battery voltage gets close to 3.7V.
A better alternative would be to use a buck-boost or just a buck converter (if the lower input voltage limit is acceptable) that can maintain a stable 3.3V output over the whole range of the LiPo battery voltage. A buck-boost converter is especially useful as it can increase (boost) or decrease (buck) the input voltage as needed.
Recommended Alternative: TPS63020
The TPS63020 from Texas Instruments is an excellent choice for this application:
  • Input Voltage Range: It supports an input voltage range of 1.8V to 5.5V, covering the entire range of a single-cell LiPo battery from fully charged to fully discharged.
  • Output Voltage: It can be configured to output a stable 3.3V, which is ideal for the ESP32.
  • High Efficiency: It offers high efficiency across a wide range of load currents, which is beneficial for battery-operated devices.
  • Package: It comes in a small QFN package, which is suitable for compact, SMD-based designs.
Circuit Design Adjustments:
  1. TPS63020 Connections:
    • VIN Pin: Connect to the positive terminal of the LiPo battery.
    • GND Pin: Connect to the negative terminal of the LiPo battery and the ESP32-WROOM-32's GND pins.
    • VOUT Pin: Set to 3.3V following the recommended circuit configuration from the datasheet, and connect to ESP32-WROOM-32:VDD (Pin 2) and the input of any bypass capacitors you're using.
  2. Input and Output Capacitors:
    • For the TPS63020, Texas Instruments recommends specific values for the input and output capacitors to ensure stable operation. Refer to the datasheet for these values, but typically a 10 µF ceramic capacitor on both input (VIN to GND) and output (VOUT to GND) should be sufficient for most applications.
  3. Feedback Components:
    • The TPS63020 typically requires feedback resistors to set the output voltage. For a 3.3V output, you'll need to select resistor values as recommended in the datasheet.
Example Connection Summary with TPS63020:
  • Connect LiPo (+) to TPS63020:VIN.
  • Connect TPS63020:VOUT to ESP32-WROOM-32:VDD (Pin 2), and to the positive sides of the output capacitors (e.g., a 10 µF ceramic capacitor).
  • Connect all GNDs together: LiPo (-), ESP32-WROOM-32:GND (Pins 1, 15, 38, 39), and both sides of the input and output capacitors.
This recommendation considers the need for efficient power conversion over the entire LiPo battery voltage range. The TPS63020 integrates both buck and boost operations to maintain a constant voltage output, making it an ideal solution for LiPo battery-operated projects, including those utilizing the ESP32 module.
2y
quaeke

quaeke

which voltage regulator is used in Lilon32?
2y

copilot

The Lolin32, a popular development board based on the ESP32, is designed to be compatible with Li-ion and LiPo batteries directly, which typically have a nominal voltage of around 3.7V but can range from about 3.0V when almost depleted to 4.2V when fully charged. To accommodate this range while providing a stable 3.3V output for the ESP32 and other onboard electronics, the Lolin32 uses a specific voltage regulator capable of efficiently converting the battery's voltage.
The Lolin32 uses the Advanced Monolithic Systems AMS1117-3.3 voltage regulator. The AMS1117-3.3 is a popular, low dropout (LDO) voltage regulator that outputs a fixed 3.3V, suitable for ESP32-based applications. It has the following key features:
  • Fixed Output: It provides a fixed output voltage of 3.3V, which is ideal for powering the ESP32 and other 3.3V logic devices.
  • Input Voltage Range: The operational input voltage of the AMS1117-3.3 generally ranges from 4.2V to 15V, making it compatible with a fully charged LiPo or Li-ion battery as well as other higher-voltage sources.
  • Current Capability: It can deliver output currents up to 800mA or 1A (depending on the specific model and thermal conditions), sufficient for the ESP32 along with peripherals.
  • Low Dropout Voltage: It has a low dropout voltage typically around 1.1V (at full load), which means the input voltage needs to be only slightly higher than the 3.3V output to maintain regulation.
However, it’s important to note that the dropout voltage may limit the LDO’s ability to provide a stable 3.3V as the battery voltage approaches its lower limit. Since LiPo and Li-ion batteries can dip below 3.7V under load or as they discharge, towards the lower end of the battery’s life, the effective output voltage might slightly drop below 3.3V before the battery is deemed depleted. This is generally acceptable for the ESP32, which can operate down to about 2.7V according to its datasheet, but it’s something to consider for other components with stricter voltage requirements.
For new designs or applications where the battery voltage can get close to or below the output voltage, a buck-boost regulator (as mentioned previously, like TPS63020) might be more suitable, as it can maintain a constant output voltage even when the input voltage drops below the desired output level.
2y
1
U1
C1
Capacitance
10uF
J1
C2
Capacitance
10uF
IC1
Not Recommended for New Designs
U2

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