3.22EjemploDRM007 Co..
3.22EjemploDRM007 Co..
3.22EjemploDRM007 Co..
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Hardware Design <strong>Co</strong>nsiderations<br />
Voltage Feedback<br />
4.11 Voltage Feedback<br />
Bus voltage is scaled down by a voltage divider consisting of R25, R10,<br />
and R9. The values are chosen such that a 500-volt maximum bus<br />
voltage corresponds to 5 volts at output V_SENSE. So,<br />
V_SENSE = V_BUS / 100.<br />
For V_BUS FAULT there are two different values, depending on the<br />
reference board. For the 115 Vac reference design board, the value is<br />
chosen for 250 Vdc maximum, and 400 Vdc maximum for the 230 Vac<br />
reference design board. The LM393 is used for the voltage FAULT<br />
signal, which is shared with the current FAULT signal of the circuit shown<br />
in Figure 4-12. The voltage feedback circuitry and voltage FAULT<br />
detector (V_LIMIT_OC) is shown in Figure 4-13.<br />
C20<br />
10pF<br />
V_SENSE<br />
R25<br />
500K 1%<br />
R10<br />
500K 1%<br />
R9<br />
10K 1%<br />
V_BUS<br />
VCC<br />
R14<br />
15K<br />
R11<br />
10k 1%<br />
C43<br />
68pF<br />
2<br />
3<br />
+15V<br />
+<br />
-<br />
8 4<br />
1<br />
LM393D<br />
IC7A<br />
V_LIMIT_OC<br />
R12<br />
(10k 1% @ 127VAC) (2.5k 1% @ 230VAC)<br />
C21<br />
22pF<br />
C3<br />
0.1uF<br />
Figure 4-13. Voltage Feedback and Fault Detector<br />
BLDC Motor <strong>Co</strong>ntrol Board for Industrial and Appliance Applications<br />
DRM007<br />
MOTOROLA Hardware Design <strong>Co</strong>nsiderations 67
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