Pololu 2756 - Dual MC33926 DC Motor Driver for Raspberry Pi (assembled)

Description

The Pololu 2756 Dual MC33926 Motor Driver is an expansion board designed for Raspberry Pi single-board computers equipped with a 40-pin GPIO connector, such as Raspberry Pi A+, B+, Pi 2, or Pi 3. The module allows control of two bidirectional brushed DC motors using MC33926 H-bridge motor driver ICs from Freescale. The driver circuits operate within a voltage range of 5 V to 28 V and can deliver up to 3 A of continuous current per channel and up to 5 A peak current for short durations.

The driver uses Raspberry Pi hardware PWM signals to control motor speed and DIR signals to change the rotation direction. The default configuration uses six GPIO pins for motor control and two additional pins for reading status outputs from the driver ICs. The controller supports PWM signals up to 20 kHz, enabling smooth and quiet motor speed regulation.

                      Example usage with Raspberry Pi Model B+                                                                                  Cuttable traces

Additional logic circuitry on the board simplifies motor control in drive/brake mode, allowing a more linear relationship between PWM duty cycle and motor speed. Built-in indicator LEDs show the state of the motor outputs, enabling quick verification of operation even when no motors are connected.

The module includes reverse polarity protection on the motor power supply, undervoltage protection, and output short-circuit protection. The MC33926 driver ICs also provide internal current limiting and thermal protection, which reduce output power if current or temperature limits are exceeded.

The board maintains the mechanical format compatible with the Raspberry Pi HAT standard, although it does not include the EEPROM used for HAT identification. A footprint for installing such an EEPROM is available on the board, allowing expanded functionality in more advanced projects.

Features

• Driver IC: 2 × MC33926
• Driver type: dual H-bridge for brushed DC motors
• Compatible devices: Raspberry Pi A+, B+, Pi 2, Pi 3
• Motor supply voltage range: 5 - 28 V
• Continuous current: 3 A per channel
• Peak current: 5 A per channel
• Maximum PWM frequency: 20 kHz
• Control method: PWM + DIR
• Number of motors supported: 2
• Reverse polarity protection
• Short-circuit protection
• Thermal protection
• Undervoltage protection
• Status flag outputs (SF)
• Motor activity indicator LEDs
• GPIO connector: 2 × 20 pin (2.54 mm pitch)
• Motor and power connectors: 5 mm terminal block

Kit includes

• Pololu Dual MC33926 Motor Driver for Raspberry Pi x1
• M2.5 mounting standoff set
• Mounting screws and nuts