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8-6
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2600S-901-01 Rev. C / January 2008
Section 8: Source-Measure Concepts
Series 2600 System SourceMeter® Instruments Reference Manual
Maximum duty cycle equation
DC
MAX
P
CS
T
DER
–
(
)
V
OA
V
B
–
(
)
V
B
( )
–
V
OA
V
P
–
(
)
I
P
( )
---------------------------------------------------------------------------------
100
×
2
≤
1
NOTE When attempting to determine the maximum duty cycle where the off
state will be 0V or 0A:
• I
B
is 0
• I
P
and V
P
are the voltage and current levels when the
SourceMeter is on.
CAUTION
This maximum duty cycle equation is an approximation. In general, if the
duty cycle calculation yields a number > 90%, then DC under those
conditions should not cause the SourceMeter to overheat. However, if the
calculation yields a number < 10%, the calculated duty cycle should not be
exceeded by more than 0.5% to avoid potential overheating.
Table 8-2
Model 2601/2602 Maximum Duty Cycle equation constants
Constant
100mV range
1V range
6V range
P
HS
56
56
56
V
OA
18
18
18
Table 8-3
Model 2611/2612/2635/2636 Maximum Duty Cycle equation constants
Constant
100mV range
1V range
6V range
P
HS
56
56
56
V
OA
18
18
18
Examples
Example 1:
Using a Model 2611 to charge a 5V battery with 1.5A, while operating at 50°C ambient
temperature; what is the maximum duty cycle?
1. Equations apply to both channels, sinking or sourcing power simultaneously. If a duty cycle less than 100% is required to avoid
overheating, the maximum on time must be less than 10 seconds