MLAB
Module
control dcmotor h-bridge

MPC17511HB01

The module uses two MC17511A H-Bridges. Power supply is 2.0-6.8V, current 1A, max 3A (per bridge)

This is an open-source hardware design, one of the modules from the MLAB labolatory system.

MPC17511HB01

H‑Bridge motor driver module (2×) using NXP/Freescale MPC17511A.

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Overview

  • Two independent full H‑bridges (U1, U2) for driving two DC motors
  • Separate supplies for logic (VDD) and motor power (VM)
  • Designed for battery‑powered robots and small mechatronics
  • Supports PWM up to 200 kHz (modulation on INx or ENx)

Electrical specifications

Parameter Value Notes
Motor supply (VM) 2.0 – 6.8 V Absolute max 8.0 V
Logic supply (VDD) 2.7 – 5.7 V Absolute max 7.0 V
Output current (per bridge) 1 A continuous Up to 3 A peak
HS+LS on‑resistance \~0.45 Ω typ. Per bridge path
Logic current ≤ 3 mA No load
PWM frequency 0 – 200 kHz DC (static) operation allowed
Module size (W×D×H) 40 × 30 × 15 mm Height over base

Signals & connectors

Each bridge (A/B) exposes the following signals.

  • VM — Motor supply input (2.0–6.8 V)
  • VDD — Logic supply input (2.7–5.7 V)
  • PGND, LGND — Power/logic grounds (tie at the module)
  • OUT1x, OUT2x — Motor outputs (channel x = A/B)
  • IN1x, IN2x — Direction inputs
  • ENx — Enable input (can be PWM’d)
  • GIN#, GOUT — Gate‑drive I/O for an optional external high‑side N‑FET (not populated on the module)

Note: The IC separates VM and VDD, allowing direct battery drive for the motor while powering the controller from a regulated VDD.

Control (functional summary)

  • ENx = H, IN1x = H, IN2x = L → Forward (OUT1x = H, OUT2x = L)
  • ENx = H, IN1x = L, IN2x = H → Reverse (OUT1x = L, OUT2x = H)
  • ENx = H, IN1x = H, IN2x = H → Brake (low‑side conduction)
  • ENx = H, IN1x = L, IN2x = L → Coast (outputs off/high‑Z)
  • ENx = L → Bridge disabled / low‑power

Refer to the MPC17511A datasheet for the complete truth table and timing.

Application notes

  • Motor EMI suppression: Place a 4.7 nF ceramic directly across the motor terminals. If needed, add small series chokes in both motor leads.
  • Power domain isolation: Keep motor current loops short. Feed the controller from VDD via an RC/LC filter and regulator. Star‑connect grounds; join the controller ground to module ground, not directly at the battery.
  • Reverse‑polarity & back‑EMF: Input diodes protect against reversed supply. A Zener clamp on VM limits voltage if the motor back‑drives the bridge (e.g., someone spins the motor by hand). Keep VM < 8 V at all times.
  • Defined input state: The IC does not include internal pull‑downs on IN1x/IN2x. To prevent a floating state at power‑up, populate 100 kΩ pull‑downs from each IN1x and IN2x to GND (four resistors total across both bridges).

Assembly notes

  • SMD components are on the bottom; pin headers and mechanical hardware are on the top.
  • Solder fine‑pitch ICs first; use minimal solder and appropriate SMD flux. Diode cathodes and capacitor positive pads are rounded in the silkscreen for orientation.

Typical use

  1. Power VDD and VM with current‑limited supplies; slowly raise VM to \~5 V during bring‑up.
  2. Drive IN1x/IN2x/ENx per the functional summary and verify motor direction and braking.
  3. Apply PWM (0–200 kHz) on INx or EN as required by your control strategy.