Motor Driver Guide (IBT-2) - EEET2610

Overview

The IBT-2 motor driver (based on BTS7960 chip) is a high-current H-bridge that allows bidirectional control of DC motors. Understanding how it works is essential for motor control.

IBT-2 Specifications

Key Features

Chip: BTS7960 dual H-bridge
Supply Voltage: 5.5V - 27V
Motor Voltage: 6V - 27V
Max Current: 43A continuous (per motor)
Peak Current: ~100A (brief surges)
PWM Frequency: Up to 25kHz
Logic Voltage: 3.3V or 5V compatible
Protection: Over-current, over-temperature, under-voltage

How H-Bridges Work

An H-bridge allows motor direction control by switching which motor terminal is connected to power/ground:

Motor Direction Control:

Forward:          Backward:         Brake:
┌─[+12V]         ┌─[+12V]          ┌─[+12V]
│                │                 │
S1 ON            S1 OFF            S1 OFF
│                │                 │
├─[M]─┤          ├─[M]─┤           ├─[M]─┤
│     │          │     │           │     │
S4 ON S2 OFF     S4 OFF S2 ON      S4 ON S2 ON
│     │          │     │           │     │
└─[GND]          └─[GND]           └─[GND]

Current: →       Current: ←        Current: 0

Four switches form an “H” shape around the motor, hence “H-bridge”.

IBT-2 Pin Configuration

Power Pins

Pin	Function	Connection
B+	Motor Power (+)	12V battery positive
B-	Motor Ground (-)	12V battery negative / GND
M+	Motor Terminal +	Motor wire 1
M-	Motor Terminal -	Motor wire 2

Logic Pins

Pin	Function	Connection	Notes
RPWM	Right PWM	ESP32 GPIO (e.g., GPIO 4)	Forward direction PWM
LPWM	Left PWM	ESP32 GPIO (e.g., GPIO 16)	Reverse direction PWM
R_EN	Right Enable	3.3V or 5V	Enable right side (can connect to GPIO for enable/disable)
L_EN	Left Enable	3.3V or 5V	Enable left side
R_IS	Right Current Sense	Optional	Analog output proportional to current
L_IS	Left Current Sense	Optional	Analog output proportional to current
VCC	Logic Power	5V from ESP32	Powers control logic
GND	Logic Ground	ESP32 GND	MUST connect to ESP32 GND

Critical: Connect GND between ESP32 and IBT-2! Otherwise PWM signals won’t work correctly.

Wiring Diagram

Basic Connection

ESP32                    IBT-2 Driver              DC Motor
                                                   
GPIO 4  ─────────────→  RPWM                      
GPIO 16 ─────────────→  LPWM                      
3.3V    ─────────────→  R_EN                      
3.3V    ─────────────→  L_EN                      
5V      ─────────────→  VCC                       
GND     ─────────────→  GND                       
                                                   
                         B+   ←──── 12V Battery (+)
                         B-   ←──── Battery (-)    
                         M+   ────→  Motor (+)     
                         M-   ────→  Motor (-)     

With Enable Control (Optional)

ESP32                    IBT-2                     
                                                   
GPIO 4  ─────────────→  RPWM                      
GPIO 16 ─────────────→  LPWM                      
GPIO 17 ─────────────→  R_EN  (enable/disable control)
GPIO 17 ─────────────→  L_EN  (same GPIO for both)
5V      ─────────────→  VCC                       
GND     ─────────────→  GND                       

Control Methods

Method 1: Dual PWM (Recommended)

Control speed AND direction with two PWM signals: Forward:

RPWM: PWM signal (0-255)
LPWM: 0 (LOW)

Backward:

RPWM: 0 (LOW)
LPWM: PWM signal (0-255)

Brake:

RPWM: 0
LPWM: 0

// Function to drive motor
void driveMotor(int speed) {
  // speed: -255 (full reverse) to +255 (full forward)
  
  if (speed > 0) {
    // Forward
    ledcWrite(RPWM_CHANNEL, speed);
    ledcWrite(LPWM_CHANNEL, 0);
  }
  else if (speed < 0) {
    // Reverse
    ledcWrite(RPWM_CHANNEL, 0);
    ledcWrite(LPWM_CHANNEL, -speed);  // Make positive
  }
  else {
    // Stop / Brake
    ledcWrite(RPWM_CHANNEL, 0);
    ledcWrite(LPWM_CHANNEL, 0);
  }
}

Method 2: Sign-Magnitude (Alternative)

One PWM for speed (magnitude)
One digital pin for direction (sign)

Not recommended for IBT-2 as it wastes one PWM-capable pin.

Example Code

Complete Motor Control

#include <Arduino.h>

// Pin definitions
#define RPWM_PIN  4
#define LPWM_PIN  16
#define R_EN_PIN  17
#define L_EN_PIN  17  // Can use same pin for both enables

// PWM configuration
#define RPWM_CHANNEL  0
#define LPWM_CHANNEL  1
#define PWM_FREQ      5000  // 5kHz
#define PWM_RES       8     // 8-bit (0-255)

void setupMotorDriver() {
  // Configure PWM channels
  ledcSetup(RPWM_CHANNEL, PWM_FREQ, PWM_RES);
  ledcSetup(LPWM_CHANNEL, PWM_FREQ, PWM_RES);
  
  // Attach pins to channels
  ledcAttachPin(RPWM_PIN, RPWM_CHANNEL);
  ledcAttachPin(LPWM_PIN, LPWM_CHANNEL);
  
  // Enable pins
  pinMode(R_EN_PIN, OUTPUT);
  pinMode(L_EN_PIN, OUTPUT);
  digitalWrite(R_EN_PIN, HIGH);  // Enable driver
  digitalWrite(L_EN_PIN, HIGH);
  
  // Start stopped
  ledcWrite(RPWM_CHANNEL, 0);
  ledcWrite(LPWM_CHANNEL, 0);
}

void setMotorSpeed(int speed) {
  // Constrain to valid range
  speed = constrain(speed, -255, 255);
  
  if (speed > 0) {
    ledcWrite(RPWM_CHANNEL, speed);
    ledcWrite(LPWM_CHANNEL, 0);
  }
  else if (speed < 0) {
    ledcWrite(RPWM_CHANNEL, 0);
    ledcWrite(LPWM_CHANNEL, -speed);
  }
  else {
    ledcWrite(RPWM_CHANNEL, 0);
    ledcWrite(LPWM_CHANNEL, 0);
  }
}

void setup() {
  Serial.begin(115200);
  setupMotorDriver();
  Serial.println("Motor driver initialized");
}

void loop() {
  // Test sequence
  Serial.println("Forward slow");
  setMotorSpeed(100);
  delay(2000);
  
  Serial.println("Forward fast");
  setMotorSpeed(200);
  delay(2000);
  
  Serial.println("Stop");
  setMotorSpeed(0);
  delay(1000);
  
  Serial.println("Reverse slow");
  setMotorSpeed(-100);
  delay(2000);
  
  Serial.println("Stop");
  setMotorSpeed(0);
  delay(2000);
}

PWM Frequency Selection

Frequency Trade-offs

Frequency	Pros	Cons	Use Case
1-5 kHz	Quiet motor	Visible PWM flicker	Good default
10-20 kHz	Very smooth	Audible whine	Silent operation
25+ kHz	Ultrasonic (silent)	Higher switching losses	Professional

Recommendation: Start with 5kHz, adjust if needed.

#define PWM_FREQ  5000  // 5kHz - good balance

Current Sensing (Optional)

IBT-2 has R_IS and L_IS pins that output voltage proportional to current:

Current (A) = V_IS / 0.00044  (approximately)

#define R_IS_PIN  34  // ADC pin

void readMotorCurrent() {
  int adc_value = analogRead(R_IS_PIN);
  float voltage = adc_value * (3.3 / 4095.0);
  float current = voltage / 0.00044;  // Approximation
  
  Serial.print("Motor current: ");
  Serial.print(current);
  Serial.println(" A");
}

Current sensing calibration varies by board. Measure with multimeter to verify.

Thermal Management

Heat Dissipation

BTS7960 chips can get HOT (60-80°C) during operation: Cooling Methods:

Ensure airflow around drivers
Don’t enclose in sealed box
Add heatsinks if running high current
Monitor temperature during testing

Thermal Shutdown:

BTS7960 has built-in thermal protection
Shuts down if overheating (~150°C junction temp)
Automatically recovers when cooled

Protection Features

Over-Current Protection

Automatic current limiting
No external fuse needed
Protects both motor and battery

Under-Voltage Lockout

Prevents operation below ~5.5V
Protects against brownout conditions

Diagnostic Outputs

R_IS and L_IS can indicate faults
Very high voltage = over-current event

Troubleshooting

Motor doesn't spin

Check:

Power connected (B+, B-)
Motor connected (M+, M-)
Enable pins HIGH (R_EN, L_EN)
PWM signal present (measure with oscilloscope or LED)
Common ground ESP32 ↔ IBT-2

Debug:

digitalWrite(R_EN_PIN, HIGH);
ledcWrite(RPWM_CHANNEL, 128);  // 50% duty
// Motor should spin

Motor spins wrong direction

Solution:

Swap M+ and M- motor wires
OR swap RPWM/LPWM in code

Motor stutters or jerks

Causes:

PWM frequency too low
Voltage drop under load
Loose connections

Solutions:

Increase PWM frequency (10-20kHz)
Use thicker wires for power
Add bulk capacitor near driver (1000µF, 16V+)
Check all connections

Driver gets very hot

Normal if:

Running high current (>2A)
Continuous operation

Reduce heat:

Add heatsink
Improve airflow
Reduce motor load
Use lower PWM frequency (reduces switching loss)

Driver shuts down

Causes:

Over-current protection triggered
Over-temperature protection
Under-voltage

Solutions:

Reduce motor load
Improve cooling
Check battery voltage (should be >11V under load)
Wait for driver to cool, then retry

Safety Practices

Important Safety Rules:

Never connect/disconnect while powered
Verify polarity before applying power
Start with low PWM (20-30%) for testing
Monitor current draw (should be <3A per motor typically)
Have emergency stop method ready
Keep clear of moving parts during testing

Comparison with Other Drivers

Driver	Max Current	Voltage	Cost	Notes
IBT-2 (BTS7960)	43A	5.5-27V	~$7	Best for this project
L298N	2A	5-35V	~$3	Too weak for 12V motors
DRV8833	1.2A per channel	2.7-10.8V	~$5	Too weak
VNH5019	12A	5.5-24V	~$15	Good alternative
ESC (Electronic Speed Controller)	Varies	Varies	$10-30	For brushless motors only

Why IBT-2? High current capacity, low cost, easy to use, perfect for our 12V DC motors with encoders.

Next Steps

DC Motor Control

Implement closed-loop motor control with PID

Unit Testing

Test motor driver systematically

Hardware Reference

Detailed motor driver specifications

Code Examples

Complete PID controller code

References

[1] BTS7960 Datasheet: https://www.infineon.com/dgdl/Infineon-BTS7960-DS-v01_00-EN.pdf [2] DroneBot Workshop - DC Motor Drivers: https://dronebotworkshop.com/dc-motor-drivers/ [3] IBT-2 Guide: https://www.14core.com/wiring-the-ibt-2-h-bridge-motor-driver/

WP1: MATLAB Simulation

WP2: Prototyping

WP3: Embedded Systems

WP4: ROS2 Setup

WP4: Robot Description

WP4: Control

WP4: Localization

WP4: Mapping

WP4: Navigation

WP4: Sensors

WP5: Integration & Presentation

​Overview

​IBT-2 Specifications

​Key Features

​How H-Bridges Work

​IBT-2 Pin Configuration

​Power Pins

​Logic Pins

​Wiring Diagram

​Basic Connection

​With Enable Control (Optional)

​Control Methods

​Method 1: Dual PWM (Recommended)

​Method 2: Sign-Magnitude (Alternative)

​Example Code

​Complete Motor Control

​PWM Frequency Selection

​Frequency Trade-offs

​Current Sensing (Optional)

​Thermal Management

​Heat Dissipation

​Protection Features

​Over-Current Protection

​Under-Voltage Lockout

​Diagnostic Outputs

​Troubleshooting

​Safety Practices

​Comparison with Other Drivers

​Next Steps

DC Motor Control

Unit Testing

Hardware Reference

Code Examples

​References

Overview

IBT-2 Specifications

Key Features

How H-Bridges Work

IBT-2 Pin Configuration

Power Pins

Logic Pins

Wiring Diagram

Basic Connection

With Enable Control (Optional)

Control Methods

Method 1: Dual PWM (Recommended)

Method 2: Sign-Magnitude (Alternative)

Example Code

Complete Motor Control

PWM Frequency Selection

Frequency Trade-offs

Current Sensing (Optional)

Thermal Management

Heat Dissipation

Protection Features

Over-Current Protection

Under-Voltage Lockout

Diagnostic Outputs

Troubleshooting

Safety Practices

Comparison with Other Drivers

Next Steps

References