H Bridge Matrix

Description

An H-bridge circuit typically provides motor control in robotic designs. Low voltage, low amperage control signals (TTL) are used to control motors. The H-Bridge can interpret these signals into a Motor Go Forward, Motor Go Backward, Motor Stop commands. Often speed can be implemented using PWM (Pulse-width modulation) through a H-Bridge. H-Bridges are extremely important in robotics. It is like the connection between the brains and the muscle of a robot. The brains being a computer or micro-Processor, and the muscles being a motor. This Matrix (when it is somewhat completed) should help you step through the process of selecting an appropriate H-Bridge design for your application.

 Terms

• Ampere  - (symbol A) the unit of measure for electrical current
• BJT - a common often inexpensive transistor
• Ground - the negative part of a battery :)
• Inductance - The magnetic field that is generated when a current is passed through an inductor, typically a wire coil. Important, because a motor which is spinning is also a generator. The current generated from this can (and has) put many H-bridges in Magic Smoke mode.
• Load - the work a motor is doing
  • No-load - is the speed and current drawn by a motor when there is no external load
  • Stalled - is the current and torque of a motor when so much load is put on the shaft, the motor does not turn
  • Rated - maximum load conditions which the motor can be operated continuously
• Magic Smoke - (slang) the smoke released from your circuit, which previously made it work. When a circuit becomes overloaded and components burn, they make magic smoke.
• MOSFET - a silicon switch which is capable of switching a considerable amount of current, typically more than BJTs. Due to the fact that MOSFETs conduct less when heated, they can be ganged together to provide massive current capability. BJTs in contrast conduct more when they get hot, and will destroy themselves in similar conditions.
• Ohm - a unit of measure for electrical resitance
• Ohm's law - a helpful formula for figuring out how much work your circuit can do, before going into "Magic Smoke" mode. I = V/R. Current = Voltage / Resistance
• Shoot Through - a term describing when some of the switches in an h-bridge do not open or close at the appropriate time. Shoot through shorts the power and can lead to circuit destruction. It is a good thing to avoid when possible. Some h-bridges are designed to prevent shoot through, other designs leave it to control circuitry.
• Short - a term describing power from a circuit going directly to ground without resistance. Another good thing to avoid. It can destroy batteries, circuits, and the wire or trace which was shorted.
• VCC, VDD, V+, VS+, PWR, + Positive supply voltage
• VEE, VSS, V-, VS-, GND, - Negative supply voltage
• Volt- (symbol V) the unit of measure for electrical potential/pressure
• Sign Magnitude - a method of using 2 inputs to an h-bridge, in which one input signals direction, and a PWM input gives the magnitude of drive.
• Locked Antiphase - input method where direction and magnitude are a single PWM input. At 50% duty the motor is stopped, lowering the duty percent would increase drive one direction, raising the duty cycle would increase in the opposite direction. Offers true 4 quadrant control of motors (CW driven, CW regenerating, CCW driven, CCW regenerating), but increases switching which increases heat.

How it works

 How to select the appropriate H-Bridge design

Measure resistance of the coil of your motor Image:Motor resistance.jpgTo find the stall current of your motor use Ohm's Law V/R=I (Current = Voltage/Resistance). For example if you measure the resistance of a motors leads at 2.4 Ohms and your battery is 24 volts, your stall current will be : 24 volts / 2.4 Ohms = 10 Amps. So if your motor stalls, your circuit should be protected or capable of handling 10 amps.

 BOA's Brilliant Hybrid H Bridge

BOA's Brilliant Hybrid H Bridge
Description	BaseOverApex's design of a great Hybrid H-bridge. The hybrid is a combination of relays and MOSFETs. The relays are for forward and reverse switching. The MOSFETS can accept a high frequency PWM for speed control. This design has been built (not just theory) and is currently powering one of BOA's great bots. Hopefully he will post a version of the PCB art - although it might be good to rework it so that the PIC is not part of the design, as others might be using different methods of control.
Original Author	BaseOverApex
Built By	BaseOverApex,
Max Current	10 Amps
Max Voltage	12 Volts
Build Time	3 Days?
Pros
Cons	Schematic is completely wrong at the moment - will fix
Max PWM Frequency
Features	forward, reverse, pwm speed control, current overload protection, fuse
Parts List
Schematic
BreadBoard	Image:M Boa B.jpg
Gerber	Image:M Gerber.jpg

 BOA's Brilliant Hybrid H Bridge - Robologist Mod

BOA's Brilliant Hybrid H Bridge - Robologist Mod
Description	BaseOverApex's design of a great Hybrid H-bridge. The hybrid is a combination of relays and MOSFETs. The relays are for forward and reverse switching. The MOSFETS can accept a high frequency PWM for speed control. This design has been built (not just theory) and is currently powering one of BOA's great bots. Hopefully he will post a version of the PCB art - although it might be good to rework it so that the PIC is not part of the design, as others might be using different methods of control.
Original Author	BaseOverApex robologist
Built By
Max Current	15 Amps - limit by relay
Max Voltage	12 Volts to 15 Volts
Build Time	3 Days?
Pros	strong, low cost
Cons	not quicklyswitchable forward to reverse, limit by relay
Max PWM Frequency
Features	reverse flyback diodes, MOSFET driver
Parts List	Desig Qty Part# Each Total Dist Description *K1,K2 2 PB897-ND $4.44 $8.88 Digikey Tyco PCLH-202D1SP,000 12VDC/75 mA coil, 15A relay *Q1,Q2 2 IRFZ44NPBF-ND $1.89 $3.78 Digikey IRF IRFZ44NPBF 49A 55v N-chan FET TO-220 *Q3,Q4 2 P2N2222AGOS-ND 0.36 0.72 Digikey On Semi P2N2222AG 600mA 40v NPN GP BJT TO-92 *D1-D8 8 497-2753-5-ND $1.09 $8.72 Digikey STMicro STPS1545D 15A 45v Schottky rectifier diode *U1 1 TC4427CPA-ND $1.05 $1.05 Digikey Microchip TC4427CPA 1.5A MOSFET driver *C1 1 4035PHCT-ND 0.81 0.81 Digikey Vishay 220 uF 35 v Electrolytic Cap * Total $23.96
Schematic
BreadBoard	Image:M relayhp B.jpg
Gerber	Image:M relayhp gerber.jpg

 SINGLE CHIP N-CHANNEL FET BRIDGE

SINGLE CHIP N-CHANNEL FET BRIDGE
Description	Design which contains a very small amount of components for a very large capacity H-Bridge.
Original Author	GroG
Built By
Max Current	30 Amps
Max Voltage	50 Volts
Build Time	3 Days?
Pros	Very small number of components, includes a under current protection line, will not "shoot through"
Cons	Schematic is completely wrong at the moment - will fix
Max PWM Frequency
Features	forward, reverse, pwm speed control, current overload protection
Parts List
Schematic
BreadBoard	Image:M FET B.jpg
Gerber	Image:M FET Gerber.jpg

 SIMPLE LOW POWER NPN PNP H-Bridge

 SINGLE CHIP CONTOLLERS

 Simple P-channel over N-channel h-bridge

Simple P-channel over N-channel h-bridge
Description	Basic low part count P over N h-bridge
Original Author	robologist
Built By
Max Current	80 Amps?
Max Voltage	12-15 Volts limit by driver and configuration
Build Time	2 hours?
Pros	Very few parts, cheap
Cons	No shoot through protections, uses 4 inputs, untested Could be improved by connecting upper and lower inputs, then adding an inverter attached between right and left sides for lock antiphase single input drive. Test shoot-through with uppers/lowers connected for feasibility.
Max PWM Frequency
Features	forward, reverse, pwm speed control
Parts List	Desig Qty Part# Each Total Dist Description *U1,U2 2 579-TC4427ACPA $1.36 $2.72 Mouser Microchip TC4427CPA 1.5A MOSFET driver *Q1,Q2 2 726-SPP80P06P $3.02 $6.04 Mouser Infineon SPP80P06N P-ch 60V 80A FET TO-220 *Q3,Q4 2 726-IPB080N06NG $2.11 $4.22 Mouser Infineon IPB080N06N G N-ch 60V 80A FET TO-220 *C1 1 647-UVY1E221MED1TA 0.11 0.11 Mouser Nichon 220 uF 25 v Electrolytic Cap *total $13.09
Schematic
BreadBoard
Gerber