Motor Driver Module Symbol
Definition: The Motor Driver Module symbol represents an integrated PWM motor controller IC or module — such as the TB6612FNG or DRV8833 — that accepts low-current logic control signals (IN1, IN2) and a power supply (VCC) to drive a DC motor's positive (M+) and negative (M-) terminals with bidirectional, PWM-controlled current, as used in robotics, embedded systems, and motor control circuit diagrams.
Also known as: H-bridge module, DC motor driver, PWM motor controller, TB6612 module, DRV8833 module, dual H-bridge driver.
What the Motor Driver Module symbol means
The Motor Driver Module symbol in a circuit diagram represents a self-contained module or IC that interfaces a microcontroller's low-power logic signals to a DC motor requiring higher current. The module contains an H-bridge circuit (or dual H-bridge for two-motor control) that switches the motor supply voltage to the M+ and M- motor terminals in a direction and speed determined by the logic states of IN1 and IN2 and the duty cycle of any PWM signal applied.
The symbol communicates that this block is the power-stage intermediary: the microcontroller cannot drive a motor directly due to insufficient current capability, so the motor driver module acts as a current amplifier and directional switch. The VCC pin powers the motor supply rail; the logic supply is often derived separately or from the same VCC.
How to identify the Motor Driver Module symbol
The Motor Driver Module symbol is drawn as a rectangular block with five key pins: IN1 and IN2 at the top left and centre (logic control inputs), VCC at the top right (motor power supply), M+ at the bottom centre-left (motor positive output), and M- at the bottom centre-right (motor negative output). The block is labelled 'Motor Driver', 'H-Bridge', or with the IC part number (e.g. 'TB6612' or 'DRV8833').
Function in a circuit
The motor driver module accepts two logic-level control signals (IN1, IN2) from a microcontroller and uses them to configure the H-bridge switching transistors, allowing current to flow through the connected DC motor in either direction. When IN1=HIGH, IN2=LOW: motor spins forward (current flows M+ to M-). When IN1=LOW, IN2=HIGH: motor spins reverse. When IN1=IN2=HIGH or both LOW: motor brakes or coasts. A PWM signal on one input controls motor speed by varying the average voltage. The VCC pin supplies the motor power rail (typically 2.5 V–13.5 V for TB6612; 1.8 V–7 V for DRV8833); output current is up to 1.2 A continuous (TB6612) or 1.5 A (DRV8833).
Standards: IEC vs ANSI
| IEC 60617 | Motor driver modules are represented in IEC 60617 schematic practice as a general functional block (rectangle) with labelled pins. No specific IEC 60617 sub-symbol exists for motor driver ICs; they follow IEC 60617-02 general binary logic block conventions with labelled input/output pins. |
|---|---|
| ANSI/IEEE 315 | ANSI Y32.2 / IEEE 315-1975 does not define a specific motor driver IC symbol; the rectangular functional block with labelled pins is standard ANSI practice for complex ICs and modules. Pin functions are determined by the part number and datasheet. |
| Key difference | Both IEC and ANSI/IEEE use identical rectangular block representations for motor driver modules with labelled pins. There is no glyph difference between standards; the IC part number or function label identifies the block. |
Terminals / pins
| Pin | Name |
|---|---|
| in1 | IN1 |
| in2 | IN2 |
| vcc | VCC |
| motor_a | M+ |
| motor_b | M- |
Typical values
TB6612FNG: VM (motor voltage) 2.5–13.5 V, VCC (logic) 2.7–5.5 V, output current 1.2 A continuous / 3.2 A peak per channel; DRV8833: VM 2.7–10.8 V, output current 1.5 A continuous / 2 A peak; typical PWM frequency 100 kHz max.
Where the Motor Driver Module symbol is used
- Arduino and Raspberry Pi robotics: motor driver modules bridge 5 V GPIO outputs to drive 6–12 V DC robot drive motors
- Autonomous vehicle projects: dual H-bridge modules (TB6612, L298N) drive two DC motors for differential steering
- Camera gimbal and pan-tilt mechanisms: motor driver modules provide precise bidirectional control of small geared DC motors
- 3D printer extruder and axis motors: motor driver ICs (DRV8825, A4988) drive stepper motors with microstepping control
- Conveyor and actuator control in embedded systems: motor driver modules control linear actuators and conveyor drives from a PLC or microcontroller
- Battery-powered toys and consumer electronics: compact motor driver ICs control DC motors in low-voltage, battery-constrained designs
Example
In an Arduino-based robot car schematic, the Motor Driver Module symbol (rectangular block, TB6612FNG) has IN1 and IN2 connected to Arduino digital pins D5 and D6; VCC connects to the 9 V battery positive; M+ and M- connect to the right-side DC drive motor terminals. By applying a PWM signal on IN1 and holding IN2 low, the Arduino controls motor speed and direction, while the TB6612 handles the 600 mA motor current that the Arduino pin cannot supply directly.
Key facts
- The Motor Driver Module symbol represents an H-bridge IC or module that enables a microcontroller to control DC motor direction and speed using logic-level signals.
- The five standard terminals are IN1 (direction control 1), IN2 (direction control 2), VCC (motor power supply), M+ (motor positive output), and M- (motor negative output).
- Motor direction is set by IN1 and IN2 logic levels: IN1=H/IN2=L → forward; IN1=L/IN2=H → reverse; both same → brake or coast.
- The TB6612FNG handles 1.2 A continuous (3.2 A peak) at 2.5–13.5 V motor voltage; the DRV8833 handles 1.5 A continuous at up to 10.8 V.
- PWM speed control is achieved by applying a PWM signal to one of the IN pins, varying average motor voltage and thus speed without heat-generating series resistance.
- Motor driver modules contain an internal H-bridge (four transistors in an H configuration) that routes current bidirectionally through the motor load.
- The L298N is a classic (though less efficient) motor driver IC; modern alternatives (TB6612, DRV8833, DRV8871) offer higher efficiency via MOSFET H-bridges rather than bipolar transistors.
Frequently asked questions
What does the motor driver module symbol mean in a circuit diagram?
The motor driver module symbol means the block is an H-bridge controller that accepts logic signals (IN1, IN2) from a microcontroller and supplies sufficient current to drive a DC motor bidirectionally. It is the power interface between a low-current logic device and a high-current motor load.
What does the motor driver module symbol look like?
The motor driver module symbol is a rectangle labelled 'Motor Driver' or with the IC part number (e.g. TB6612). Pins IN1 and IN2 are on the top left for control inputs, VCC on the top right for power, and M+ and M- on the bottom for the motor output connections.
How do IN1 and IN2 control a DC motor?
IN1=HIGH and IN2=LOW causes the motor driver to apply voltage from M+ to M- (forward rotation). IN1=LOW and IN2=HIGH reverses polarity (reverse rotation). IN1=IN2=HIGH engages motor braking; IN1=IN2=LOW causes the motor to coast (free-spin).
What is the difference between TB6612 and L298N motor drivers?
The TB6612FNG uses a MOSFET H-bridge (lower voltage drop, less heat, 1.2 A continuous) while the L298N uses a bipolar H-bridge (higher voltage drop, more heat, 2 A continuous). TB6612 is preferred for battery-powered and microcontroller-based designs; L298N is a legacy part still common in educational kits.
What voltage does a motor driver module support?
The TB6612FNG motor driver supports motor supply voltage (VM) from 2.5 V to 13.5 V and logic supply (VCC) from 2.7 V to 5.5 V. The DRV8833 supports VM from 2.7 V to 10.8 V. Always check the specific module datasheet for the maximum motor voltage.
Can a motor driver module control stepper motors?
Some motor driver ICs (DRV8825, A4988, TMC2208) are specifically designed for stepper motor control with microstepping. H-bridge drivers like TB6612 can control unipolar steppers with appropriate wiring, but dedicated stepper driver ICs are preferred for microstepping accuracy.
What standard defines the motor driver module symbol?
Motor driver modules follow IEC 60617-02 general IC block conventions (rectangle with labelled pins) since no dedicated IEC sub-symbol exists for motor driver ICs. ANSI Y32.2 / IEEE 315-1975 also uses a labelled rectangular block for complex ICs.
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