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1.1 Logic supply voltage (VDD)
It is possible to provide the gate driver control logic supply VDD in three alternative ways to match driver input
threshold with the controlling signals voltage swing:
•
Using the onboard 3.3 V Zener D2 regulator to supply VDD. The Zener is supplied from DC-DC input
voltage VAUX. So only the 5 V VAUX DC-DC supply input is powered to supply the whole system (default
configuration).
• Supplying externally VDD net from J9 or J10 (pin 6) with a voltage between 3 V and 5.5 V.
• Supplying externally VDD and VAUX together (VDD max. 5.5 V).
In case the default option is not used, it is required to modify JP22 according to Table 3 and R17 according to
Table 4 also to avoid regulator components damage.
Table 3. Logic supply voltage selection (VDD)
VDD JP22 Note
3.3 V, onboard (default) 2-3 closed VDD generated from VAUX with Zener diode D2
3.3 V, external Open VDD directly supplied from J9 or J10 (pin 6)
VDD = VAUX, external 1-2 closed VDD and VAUX (DC-DC supply) tied together by JP22
The R17 resistor value has been selected for using 5 V input DC-DC module. If a different VAUX input voltage is
used, follow
Table 4 to modify resistor R17 (which biases Zener D2) to avoid resistor overheating.
Table 4. R17 value selection with a 3.3 V Zener diode D2 regulator
DCDC module supply input voltage VAUX R17 JP22
3.3 V Do not care 1-2 closed
5 V (default) 240 Ω 2-3 closed or JP22 open
12 V 1200 Ω 2-3 closed or JP22 open
15 V 1500 Ω 2-3 closed or JP22 open
24 V 2700 Ω 2-3 closed or JP22 open
UM2754
Logic supply voltage (VDD)
UM2754 - Rev 1
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