eChook GPT Documentation
  • Welcome to the eChook nano documentation
  • System Overview
  • The eChook Nano Kit
    • Versions
  • Build Instructions (Kit V1.x)
    • Build Steps Photos
    • First Power On
  • Build Instructions (Kit V2+)
  • Programming the Arduino
    • Install Arduino IDE
    • Arduino Drivers
    • Download the eChook Arduino Code
    • Programming the Arduino
  • Setting up the Bluetooth
    • Pairing with a phone
  • Connecting the eChook to the Car
    • Power and Voltage
    • Current Sensor
    • Throttle Input
    • External Buttons and Brake
    • Temperature Sensors
    • Wheel and Motor RPM
    • PWM Output
  • Calibrating the eChook
    • Wheel Speed and Motor RPM
    • Temperature
    • Voltage
    • Current
  • Using the App
    • Pair eChook to Phone
    • Setting up the App
    • Logging Data
    • Lap Counting
  • Telemetry (Live Data)
    • eChook Live Data
    • Node-Red Integration
    • DIY Web Dashboard
  • Using the Data
  • Circuit Schematics
    • 12 and 24v Inputs
    • Temperature Inputs
    • Bluetooth Module
    • Throttle Input
    • Current Input
    • Button Inputs
    • RPM Inputs
    • PWM Output
    • Power Regulator
    • Expansion Port
  • All about the Arduino nano
    • The eChook nano Code
  • Bluetooth Communication
    • Bluetooth Packet Encoding
    • Bluetooth Packet Decoding
  • Experimental Section
    • GUI Calibration
  • eChook Accessories
  • DIY eChook
  • Spare Parts
  • Troubleshooting
    • Power
    • Arduino
    • Bluetooth
    • Current Sensor
    • Incorrect Data
  • Contributing
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  • Resettable Polyfuse
  • Reverse Polarity Protection
  • 5V Switching Regulator

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  1. Circuit Schematics

Power Regulator

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Last updated 11 months ago

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This schematic shows the resettable polyfuse, reverse polarity protection and the 5V regulator.

Resettable Polyfuse

FS1 is a 250mA polyfuse. If the eChook board draws more than 250mA at 24v, the resistance of this fuse will increase from milli Ohms to a few Mega Ohms, effectively cutting power to the eChook. If there is a short circuit, this will cut off the power supply, limiting any damage. It also plays a role in reverse polarity protection, described below.

Once power is removed from the fuse it resets within a few seconds.

Reverse Polarity Protection

This protects the board against the +24V and Ground being connected the wrong way around. Diode D1 is placed in reverse bias - under normal operation no current will flow through it, however if the input polarity is reversed it becomes a conductor, creating a low resistance current path from the ground rail to the 24v rail. This current all passes through the polyfuse and is considerably above its 250mA cutoff current which will cause it to break the circuit immediately.

5V Switching Regulator

Component U2 is the TRACOPOWER Switching Regulator. It takes any input voltage between 6.5V and 36V and provides a stable 5V output of up to 1A. C1 is a 22uF smoothing capacitor for the input voltage to the regulator, as specified in the datasheet.

NOTE: The regulator is a TSR-1-2450. The reference to TSR-1-24120 below it is the PCB footprint used, which is the same.