StepStick DC Driver V2

A dual DC/H-bridge driver, designed as a drop-in replacement for a standard stepstick.
Can drive two DC motors, or be used as four independent half-bridges.
Designed around the TB67H453FNG IC. Datasheets can be found here.

Specs

• Dual H-Bridge : Can drive two DC loads in both directions, or four DC loads unidirectionally
• 3.3A Max per channel
• Accepts an input power voltage from 4.5v to 44v
• Based around a 4 layer PCB, to improve heat dissipation (a heat sink and active cooling is highly recommended)
• The maximum intensity can be configured with the trimmer, by adjusting Vref
• Can be enabled or disabled with the en pin, just like a standard stepstick
• Compatible with both 5v and 3.3v logic voltage (If using 5v to power VCC, you must adjust the trimmer so that Vref stays below 3.3v!)

Pinout

You can use the Pololu_Breakout_A4988 symbol from the default KiCad library, with its accompanying default footprint. Here is a pinout correspondence for the pins :

StepStick DC Driver	Pololu A4988
OB1	1B
OB2	1A
OA2	2A
OA1	2B
IA2	DIR
IA1	STEP
IB2	RESET
IB1	MS3
MSB	MS2
MSA	MS1
VCC	VDD
NC	SLEEP

Warning

You need to add a 100uf capacitor between the VM and GND pins.

Configuration

If the resistors on the BOM are respected, the maximum intensity per channel can be configured by setting the Vref voltage :
Imax(A)=Vref(v) The driver will regulate the intensity to prevent it from getting higher.

The configuration is common to both H-bridge.

Control

Channel A and B are both controlled by their own two pins Ix1 and Ix2.
They are 3 ways to control the outputs, configured respectively by MSx :

MSx	Mode
L	Phase/Enable control
H	PWM control
Hi-z/Open	Individual half bridge control

Phase/Enable control (MSx=Low)

Ix1	Ix2	Ox1	Ox2	Mode
L	L/H	L	L	Short Brake
H	L	L	H	Reverse
H	H	H	L	Forward

PWM control (MSx=High)

Ix1	Ix2	Ox1	Ox2	Mode
L	L	Hi-Z	Hi-Z	Coast
L	H	L	H	Reverse
H	L	H	L	Forward
H	H	L	L	Short brake

Individual half bridge control (MSx=Hi-z/Open)

Ixx	Oxx	Mode
L	L	Short Brake
H	H	Reverse

Note

Current limiting does not work in half bridge mode, so beware of currents!

All

If left open, a pin will be pulled down (considered L). If you do not want to use one of the channels, you can simply not connect the output to anything.

Fabrication notes

The constraints have been set up for Aisler's Beautiful Boards service.
It is advised to use a .8mm total thickness instead of the standard 1.6mm to improve the thermal dissipation.

Real world testing

To be done.

StepStick DC Driver V1

See here.