2308-900-01 Rev. A / July 2008
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Section Topics
3-25
Model 2308 Portable Device Battery/Charger Simulator User’s Manual
Section 3: Pulse Current Measurements
TLEV values (all rising)
This pulse sequence can be measured using the continuous pulse method (see the programming
example
Continuous pulse train
). Similarly, this pulse train could be measured using the one-shot
method. For the one-shot method, the first step trigger level value could be any value for detecting
the 900 milliamp step.
Timeout setting
TOUT (TimeOUT - timeout setting) specifies the timeout length for detecting a given pulse step.
When the TOUT value is reached, an overflow value for that step reading is returned. Although all
step measurements after the first TOUT step are returned as overflow readings, all step
measurements performed before TOUT was exceeded will have correct readings.
Two timeout settings are used: one for the initial step and another for the rest of the active steps.
The setting for the initial timeout should be set slightly longer than the period of the pulse for
continuous pulse trains. The other timeout setting should cover the longest step duration. Also,
make sure to account for trigger delays when determining timeout settings. There are two possible
trigger delays: the internal trigger delay (10
μ
sec necessary for code execution), and any user
specified trigger delay (optional). The trigger delays occur before the integration process begins
but after pulse detection.
To use the pulse current step method to measure a one-shot pulse train, set the initial timeout to
the maximum setting of 60 seconds. This allows the Model 2308 to be triggered for step
measurements, then a few seconds of delay before generating the one-shot pulse train. The few
seconds of delay are required to ensure the Model 2308 is setup and ready to detect the first step
when it happens along with the rest of the steps.
Integration time
For the pulse current step method, the integration time is required to be at least 400
μ
sec less than
the step duration. This 400
μ
sec allows for the Model 2308 to complete the previous measurement
conversion and become ready for the next pulse edge. With this in mind,
Table 3-8
lists
appropriate integration times. Integration time applies to all active steps when step measurements
are requested — each step has the same integration time.
TLEV1
750 mA (1st pulse)
TLEV3
500 mA (5th pulse)
TLEV2
400 mA (4th pulse)
TLEV4 625 mA (6th pulse)
Table 3-8
Sample integration times
Pulse step duration
Step integration times
3.8 ms
≤
3.4 ms
1.25 ms
≤
0.85 ms
800
μ
sec
≤
400
μ
sec
500
μ
sec
≤
100
μ
sec
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