pcb-hbridge-cp2119l/README.md

18V 5A H-Bridge breakout board

• For driving DC motors, coils or other inductive loads
• Bi-directional output control
• Input 3.0-18V
• Output up to 5A continuous, up to 9A pulse
• Works with 1.8V to 6.0V logic level inputs
• Overcurrent protection
• Short circuit protection
• Overheat protection
• Integrated flyback diodes
• Pretty idiot-proof
• Uses CP2119L or TMI8260SP integrated circuit

Basic operation

• Logic HIGH on the FORWARD pin makes the motor spin FORWARD (M+ becomes VIN, M- becomes GND)
• Logic HIGH on the REVERSE pin makes the motor spin REVERSE (M+ becomes GND, M- becomes VIN)
• Logic HIGH on BOTH pins makes the motor ACTIVELY BREAK (M+ becomes GND, M- becomes GND)
• Logic LOW on BOTH pins makes the motor FREESPIN (M+ floats, M- floats)

"Analog" control

• The power of the motor can be precisely adjusted (0-100%) by applying a PWM SQUARE WAVE to the FORWARD/REVERSE pins
• Recommended PWM frequency: 100Hz - 5KHz
• "analogWrite()" on Arduino produces a suitable 490Hz square wave with 255 levels of control

PCB assembly / component configurations

For Voltage 3-18V and Current 0-5A (basic configuration)

• Populate the TMI8260 (duh!). Note where pin 1 (marked) goes!
• Populate '2x10uF' with included ceramic capacitors
• Populate '220uF' with included polymer aluminium capacitor. Note where the negative goes!
• Skip the additional flyback diodes
• This works with PWM frequencies up to 5KHz

For PWM frequency > 5KHz

• If the expected current is low (<3A), you can probably just use the basic configuration
• Otherwise, add 4x flyback diodes on the PCB
• SS54 or SS34 diodes, in SOD-123L package
• They are difficult to solder, sorry!

For Voltage<10V AND Current<2A:

If you don't need the high power of this chip, consider using the DRV8835 module instead. It is cheaper and comes pre-assembled.

For ONE directional control:

If you don't need bi-directional control, consider just using a N-MOSFET and flyback diode instead. Cheaper, simpler.

Built in protections

The TMI8260/CP2119 has protection features that allow it to protect ITSELF

• It cannot protect the connected motor/coil - make sure VIN is a voltage that the motor can handle!
• It cannot fully protect the power source - make sure it can handle the current the motor will take!

Overcurrent / short-circuit protection

• If the connected motor / coil attempts to take more than > 9A, overcurrent protection kicks in
• The device will stop supplying power for approx 50 microseconds, and let the current drop
• After that, the device will automatically retry applying current
• This is very helpful when starting large motors from a standstill - the surge current will be effectively limited, and the motor will slowly spin up instead of taking infinity amperes.
• This does protect the power source by limiting the consumed current to approx 9A
• This feature relies on the inductance of the connected motor/coil. If the inductance is too low, the safety feature will not have time to react before the current becomes too high.

Overtemperature protection

• If the TMI8260 gets too hot (>150C) during continuous operation, it will temporarily stop providing power to the load
• After cooling down, it will automatically return to normal operation

Integrated flyback diodes

• Inductive loads tend to induct reverse voltages that may damage drive circuitry
• The TMI8260 has integrated flyback diodes (inside the chip) that can handle most use cases
• The PCB has space for additional external flyback diodes, for more extreme cases (see "Use cases")

Parts included in the kit:

• Breakout PCB
• TMI8260SP-MS chip
• Polymer aluminium capacitor (SHENGYANG SM227M025E0600 220uF 25V)
• 3x Ceramic capacitors (10uF 25V 0603)

Documentation

TMI8260SP-MS datasheet (in Chinese)

Future improvements

Thermal management

• Most of the heat from the IC seems to be dissipating though the OUT1 / OUT2 pins
• Therefore, the OUT1 / OUT2 polygons should be enlarged, for better cooling
• Maybe the IC should be moved more towards the middle of the board
• Right now the board can barely handle 5A

Solderability

• The large cap is very difficult to solder
  • Some thermal reliefs can make it much easier, while probably not impacting performance in any significant way
• The optional flyback diodes are difficult to solder
  • The footprint should be made hand-solderable (by enlarging the pad by a lot)

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Made at ELAB by Marek Baczynski. Find him on the ELAB slack if you have any questions