IBT-2 BTS7960 motor driver
The IBT-2 module: two BTS7960 half bridges under a heat sink, for one big brushed motor at 5.5 V to 27.5 V. Aliases: BTS7960, IBT-2, 43A.
It is the board for a car wiper motor, a scooter motor or a winch, where an L298N would melt. Each motor terminal has its own half bridge with its own PWM input and enable.
Pins
| Pin | What it does |
|---|---|
RPWM |
Drives M+: high is its high side on, low its low side on. |
LPWM |
Drives M- the same way. |
R_EN, L_EN |
Each half bridge's enable. Low switches both its transistors off. |
R_IS, L_IS |
Current sense outputs (not simulated). |
VCC |
5 V for the 74HC244 buffer the inputs go through. |
GND |
Ground. The same ground as B-. |
B+, B- |
The motor supply. |
M+, M- |
The motor. |
The truth table
| R_EN | L_EN | RPWM | LPWM | Motor |
|---|---|---|---|---|
| H | H | PWM | L | forward |
| H | H | L | PWM | reverse |
| H | H | same | same | brake |
| L | L | any | any | coast |
Tie R_EN and L_EN together to one pin (or to 5 V) and put analogWrite on
RPWM for one way and LPWM for the other, the other held low.
While it runs
The face shows what the motor is being told: off, fwd, rev or brake.
What the model gets right
From Infineon's BTS7960B datasheet:
Each half bridge's table. On-resistance: 7 mΩ high side and 9 mΩ low side,
typical at 25 °C, so a stalled motor meets almost nothing but its own winding.
The supply: off under 5.5 V and from 27.6 V, the chip's overvoltage lockout.
The buffer: the inputs are read as a 74HC chip reads them, at half its 5 V
VCC, so a 3.3 V board switches it. The 74HC244 only promises a high from 3.5 V,
so 3.3 V logic is outside its guarantee. An unwired input is not a level, so that
half bridge is off.
What it does not model
The current limit: 43 A typical on the low side (34 A at least) and 60 A on the
high side, past which the chip chops. The current sense: R_IS and L_IS give
about one 8500th of the load current while the high side is on and 4.5 mA on a
fault; here they are left alone. The module's resistors on them are not published.
Heat, the thermal shutdown and its latch. Which chip each header pin reaches is read
from what the pins do, as no schematic of the module is published.
See it in action
IBT-2 BTS7960 big motor driver ramps a 12 V motor on a lead-acid battery both ways from an Uno. Open it at /templates.
The IBT-2 motor speed control with a knob runs the same motor from a potentiometer: stop in the middle, forward one way, reverse the other, with a dead band and a ramp.