CS3351(2002) View Datasheet(PDF) - ON Semiconductor
Part Name
Description
Manufacturer
CS3351 Datasheet PDF : 8 Pages
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CS3341, CS3351, CS387
REGULATION WAVEFORMS
The CS3341/3351/387 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
“Device Driver.”
Figure 4 shows typical steady–state 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
ÎÎÎÎ
Field Driver On
Figure 4. 50% Duty Cycle,
Steady State
ÎÎÎÎÎÎ
Field Driver On
Figure 5. > 50% Duty Cycle,
Increased Load
ÎÎÎÎ
Field Driver On
Figure 6. < 50% Duty Cycle,
Decreased Load
STATOR
RECTIFIER
MR2502
MR2502
S
C3
0.047 µF
*C2
10 µF
R1
100 kΩ
R2
50 kΩ
C4
0.022 µF
R3 250 Ω
C1
0.1 µF
R4
18 kΩ
VCC
Sense
OSC
STATORSC
Driver
IGN
R6
20 kΩ
LAMP GND
R5 10 kΩ
D1
MR2502
2N6284
Power
Darlington
POWER GROUND
R7 10 Ω
R9
2.4 kΩ
MPSA13
or CS299
*Note: C2 optional for reduced jitter.
A
F
FIELD
I
Lamp Indicator
R10
510 Ω
IGNITION
SWITCH
BATTERY
Figure 7. Typical Application DIagram
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