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CS3361 Datasheet, PDF (6/8 Pages) Cherry Semiconductor Corporation – Alternator Voltage Regulator FET Driver | |||
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CS3361
REGULATION WAVEFORMS
The CS3361 utilizes proportion control to maintain
regulation. Waveforms depicting operation are shown in
Figures 4, 5 and 6, where VBAT/N is the divided down
voltage present on the Sense pin using R1 and R2 (Figure 7).
A sawtooth waveform is generated internally. The
amplitude of this waveform is listed in the electric parameter
section as proportion control. The oscillator voltage is
summed with VBAT/N, and compared with the internal
voltage regulator (VREG) in the regulation comparator
which controls the field through the output âDevice Driver.â
Figure 4 shows typical steadyâstate operation. A 50%
duty cycle is maintained.
Figure 5 shows the effect of a drop in voltage on (VBAT/N
+ VOSC). Notice the duty cycle increase to the field drive.
Figure 6 shows the effect of an increase in voltage (above
the regulation voltage) on (VBAT/N + VOSC). Notice the
decrease in field drive.
VBAT/N + VOSC
VREG
VBAT/N + VOSC
VREG
VBAT/N + VOSC
VREG
ÃÃÃÃ
Field Driver On
Figure 4. 50% Duty Cycle,
Steady State
ÃÃÃÃÃÃ
Field Driver On
Figure 5. > 50% Duty Cycle,
Increased Load
ÃÃÃÃ
Field Driver On
Figure 6. < 50% Duty Cycle,
Decreased Load
STATOR
RECTIFIER
MR2502
MR2502
MR2502
MR2502
MR2502
MR2502
C3
0.047 µF
S
A
R1
100 kâ¦
R2
50 kâ¦
*C2
10 µF
R3 250 â¦
C1
0.1 µF
R4
18 kâ¦
D1
MR2502
VCC
STATORSC R5
F
Sense
OSC
10 kâ¦
Driver
Logic level
Q1 N Channel
MTB20N20E
C4
0.022 µF
IGN
R6
20 kâ¦
LAMP GND
POWER
GROUND
I
R7 10 â¦
R9
2.4 kâ¦
MPSA13
*Note: C2 optional for reduced jitter.
FIELD
Lamp Indicator
R10
510 â¦
IGNITION
SWITCH
BATTERY
Figure 7. Typical Application DIagram
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