Specifications

REV.-A
Constant Current Drive Circuit
The constant current drive circuit is shown in Figure 2-33 (for A-phase only), and the waveforms for
each part are shown in Figure 2-34. In Figure 2-33, the reference voltage is indicated by
Vref; this voltage
determines the peak current through resistance
R30. Resistance R59 and capacitance C 15 determine
the OFF time of the chopper.
vcc= +24V
t
II ! +-l + I . /1
1
b
,
IOFF 1
1
c )
“1
COMP1 -
I
@ RSA
C15
L
i ION
J
470p
D5
RS=
R30
Gp
lsll w
Gp Gp
Vref
Figure 2-33. Constant Current Control Circuit
2-29