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The Robot Power Simple-H is a low-cost robust H-bridge
circuit suitable for use driving DC motors and other DC loads in the ~25A
and 6V-28V range. A wide range of command sources from switches to 555
timer circuits to microcontrollers, BasicStamps
and Arduinos may be used to control the
Simple-H. The classic "green" Simple-H requires 3V-5V logic
level signals on its command inputs.
The Simple-H does not have any on-board logic to interpret
R/C, serial, analog voltage or other commands. An external signal source
is required to translate command inputs into the switching signals needed
to drive the Simple-H power chips. This flexibility allows the Simple-H
to be driven from from a signal source as
simple as a pushbutton or as complex as a microcontroller or BasicStamp. Even a desktop or laptop PC can be used
through a parallel port or USB port expander. 
The Simple-H HV is a version of the Simple-H that allows
up to 28V input signals. The circuit board footprint and mounting pattern
is exactly the same between the two versions. The indicator LEDs on the
HV have a constant-current driver so their output is independent of
signal voltage and does not load the input signal. These features allow
the Simple-H to be controlled by using switches directly off the 12V or
24V battery voltage rather than requiring a 5V regulator to condition the
input command voltages. Also 12V/24V outputs from PLC modules may now be used
directly to drive a Simple-H.
Unlike many competing products which advertise similar
current ratings, the Simple-H ratings are for a period measured in
minutes or hours not a few seconds or less. One competitor even
advertises a 30A controller where the 30A rating is for "a few
milliseconds". With a Simple-H you can be sure if you need 20A of
current you can get 20A out of it for as long as you need it.
I wanted to inform you that our products passed (UL
Certification) which also means the Simple H passed. One test performed
on the Simple H that may be of interest is the cycling test. They
performed 6000 on/off cycles at full current at two second intervals (one
second on for each channel)...
- Customer Ron P from PA, USA
I just wanted to let you know that I have used the Simple
H-Bridge to overcome a problem with the auto-pilot control unit on my 40'
yacht. The Simrad autopilot installed on my
boat drives an electrically powered hydraulic control ram. The motor can
draw over 15 amps when fully loaded but has an average current of <3
amps. The J3000X control unit installed was rated for 6 amps continuous
and 10 amps for 5 seconds, which was clearly under-rated for the
application and would regularly drop out. Simrad
make a higher power control unit (J300X) with 10 amps continuous and 20
amps for 5 seconds, but it is very expensive as it contains all the
smarts of the autopilot, which I already have in the J3000X unit. So I
used one of your Simple H-Bridges, interfaced appropriately to the J3000X
and it works brilliantly. Naturally I carry a spare! Thanks for
developing a great little product.
- Customer Chris D. from Sydney, Australia
The
Simple-H has the following specifications and features:
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Supply voltage
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5V to 28V (24V
max battery rating)
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Output Current
(continuous)
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20A (25A with
fan)
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Output Current
(surge)
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>45A
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Weight
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1.3 0z
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Power chips
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2 ea. BTS7960B
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On Resistance
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.016 ohm max at
25C
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PWM Frequency
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DC to 20kHz
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Cooling
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Heatsinks and optional 20 CFM 50mm fan
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Logic Interface
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3V - 5V classic
version
4V-28V HV version
min. 2 digital signals required to drive
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Current and Temp
Limiting
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Built in to
power chips
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Current Sense
Outputs
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0.0745V per Amp
- 2.98V at 40A
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Connectors
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8-pos 0.1"
screw terminal, 2-pos fan terminal
4 each screw terminals for power wires
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Enclosure
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None
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A User
Manual and Schematic
diagram are available for more detailed information.
Six command/status connections are provided via an
8-position screw terminal on the Simple-H. The hole spacing allows a
standard 0.1" pin header to be substituted for the screw terminal if
desired. Jumpers allow the user to configure the Simple-H as a single
full H-bridge or two independent 1/2 bridge circuits. The 1/2 bridge
circuits may be ganged together for increased current handling.
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CN1 -
Command/Status Connector Pinout
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1
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PWM A - A-side 1/2
bridge control input
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2
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PWM B - B-side
1/2 bridge control input
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3
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Enable A - A or
A&B-side* enable
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4
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Current A - A or
A&B-side** current sense output
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5
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Enable B -
B-side enable
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6
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Current B -
B-side current sense output
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7
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Battery Negative
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8
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Battery Positive
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* with EA jumper
installed in J1
** with CA jumper installed in J1
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The Simple-H
uses heatsinks and heavy copper areas on the
circuit board to dissipate heat. This results in a current rating higher
than for most motor drives of similar size. To get the maximum possible
current or to run for exetended periods close
to maximum the Simple-H uses an optional cooling fan to further
dissipate heat. The fan itself is a commonly available 12V 50mm square
computer cooling fan. Mounting holes are provided at the correct
spacing to mount the fan directly over the power chips for maximum
cooling efficiency.
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Robot Power offers the Simple-H in
fully assembled units. Check the Web store for
details on prices and special offers.
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