TMC5130A DATASHEET (Rev. 1.14 / 2017-MAY-15)
16
3.4.2 Internal Regulator Bridged
In case a clean external 5V supply is available, it can be used for complete supply of analog and
digital part (Figure 3.5). The circuit will benefit from a well-regulated supply, e.g. when using a +/-1%
regulator. A precise supply guarantees increased motor current precision, because the voltage at
5VOUT directly is the reference voltage for all internal units of the driver, especially for motor current
control. For best performance, the power supply should have low ripple to give a precise and stable
supply at 5VOUT pin with remaining ripple well below 5mV. Some switching regulators have a higher
remaining ripple, or different loads on the supply may cause lower frequency ripple. In this case,
increase capacity attached to 5VOUT. In case the external supply voltage has poor stability or low
frequency ripple, this would affect the precision of the motor current regulation as well as add
chopper noise.
Well-regulated, stable
supply, better than +-5%
+5V
VSA
5V Voltage
regulator
5VOUT
4.7µ
10R
VCC
470n
Figure 3.5 Using an external 5V supply to bypass internal regulator
3.5 Pre-Regulator for Reduced Power Dissipation
When operating at supply voltages up to 46V for VS and VSA, the internal linear regulator will
contribute with up to 1W to the power dissipation of the driver. This will reduce the capability of the
chip to continuously drive high motor current, especially at high environment temperatures. When no
external power supply in the range 5V to 24V is available, an external pre-regulator can be built with
a few inexpensive components in order to dissipate most of the voltage drop in external components.
Figure 3.6 shows different examples. In case a well-defined supply voltage is available, a single 1W or
higher power zener diode also does the job.
+VM
+VM
22k
BCX56 or
similar
22k
4k7
Z5.6V e.g.
MM5Z5V6
BCX56 or
similar
100R
VSA
VSA
5V Voltage
regulator
5V Voltage
regulator
5VOUT
5VOUT
470n
16V
470n
16V
4.7µ
4.7µ
2R2
2R2
VCC
VCC
470n
470n
Simple pre-regulator for 24V up to 46V
Simple short circuit protected pre-regulator for 24V up to 46V
Figure 3.6 Examples for simple pre-regulators
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TRINAMIC [ TRINAMIC MOTION CONTROL GMBH & CO. KG. ]
