Control Systems
OBR Control Systems Inc
OBR Control Systems Inc
Telephone : +1 (248) 672-3339
32233 West 8 Mile Road
www.obrcontrolsystems.com
Livonia, Michigan 48152
USA
45 / 92
9.5 High Power PWM Outputs
This section gives access to:
Naming of output
Set inrush current threshold
Set time interval for inrush current
Set the normal fused threshold
Set the number of retries once a fault is detected before switching off
Set the time interval for fault resetting
Set frequency for pulse width modulation (PWM)
Define duty cycle map
2 high power outputs are available with PWM capability applying frequencies up to 25 kHz and of
supplying a maximum continuous current of 26..50 A each channel. Please observe that our
default maximum current level for each channel is set in accordance with Deutsch’s current limit for
the size AWG16 contacts in the Autosport 20-16 connector. The driver stages can deliver
significantly more current, but it is important to avoid overloading the wiring and contacts in the
connector.
WARNING: Do NOT connect any PWM output in parallel with any other output!
9.5.1 Half Bridge – Full Bridge
These PWM outputs are true half bridge drivers, having a top and bottom transistor.
Contrary to conventional outputs the PWM outputs are connected to ground when switched off.
By combining 2 PWM outputs you can create a full bridge which for example could be used to drive
a DC motor, turning it clockwise or anti clockwise. In this example you connect one PWM output to
one of the DC motor terminals, a second PWM output to the other DC motor terminal. Depending
on which output you activate you can make the DC motor rotate.
You can configure the PWM drivers as either digital outputs or as frequency, duty cycle controlled
outputs. In this configuration you will be able to control the speed at which the motor rotates.
The control can be extended to included position control via an analogue or digital input or by the
current draw.
9.5.2 Current Draws
Current draw can be measured on all outputs.
Outputs are protected by three current thresholds and three timers:
- OCH is the high current threshold of 100 A.
- OCL is the user defined continuous current threshold, selectable as 15, 20 or 25..50 A.
- OCS is the software selected current threshold.
