User Manual

TMCM-1311 V1.2 Hardware Manual (Rev. 1.12 / 2013-JUL-05) 13
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3.3 Power Supply
For proper operation care has to be taken with regard to power supply concept and design. The TMCM-
1311 includes about 40µF of supply filter capacitors. These are ceramic capacitors which have been
selected for high reliability and long life time. Further, the module includes a 48V suppressor diode and
additional varistor for over-voltage protection.
CAUTION!
Add external power supply capacitors!
The module contains a number of capacitors for power supply filtering. Nevertheless,
depending on operation and selected motors the resulting capacity might be not large
enough for proper supply buffering. Note: upper supply voltage limit must not be
exceeded not even for a short period of time! In this context it should be taken into
account that the module will transfer energy from the motor back into the supply rail
when the motor is working as generator e.g. during deceleration or brake conditions.
In case the power supply capacitors are not sufficient for limiting power supply rising,
additional measures have to be considered (e.g. suppressor diodes, brake resistor).
Refer to chapter 3.3.1 for further information about adding electrolytic capacitors.
Do not connect or disconnect motor during operation!
Motor cable and motor inductivity might lead to voltage spikes when the motor is
disconnected / connected while energized. These voltage spikes might exceed voltage
limits of the driver MOSFETs and might permanently damage them. Therefore, always
disconnect power supply before connecting / disconnecting the motor.
Keep the power supply voltage below the upper limit of 52.5V!
Otherwise the driver electronics will seriously be damaged! Especially, when the
selected operating voltage is near the upper limit a regulated power supply is highly
recommended.
There is no reverse polarity protection!
The module will short any reversed supply voltage due to internal diodes of the driver
transistors.
3.3.1 Adding an Electrolytic Capacitor
TRINAMIC recommends connecting an electrolytic capacitor of significant size to the power supply lines
next to the TMCM-1311. As rule of thumb, around 1000µF of capacity should be added for 1A of module
power supply input current.
The additional electrolytic capacitor
- serves for power stabilization (buffer) and filtering.
- reduces voltage spikes, which can occur in consequence of the combination of high inductance
power supply wires and ceramic capacitors.
- limits the slew rate of the power supply voltage at the module. This is reasonable, because the low
ESR (Equivalent Series Resistance) of ceramic-only filter capacitors may cause stability problems with
some switching power supplies.
Power
connector
V
DIGITAL
V
DRIVER
SMBJ48A
4 x 10µF
GND
TMC262 + MOSFETs
(stepper driver)
GND
SK36
SMBJ48A
1µF
GND
Supply of other circuits
via on-board regulators
GND
V
DIGITAL
on I/O connector 0 + 1
GND
48VDC
250A
GND
48VDC
250A
Figure 3.2 TMCM-1311 power supply concept