20
Advanced features
Charger channel (#2)
Advanced features
Simulating battery impedance
The electronic resistance of batteries varies according to a variety of factors such as chemis-
try, cell construction, number of charge/discharge cycles, temperature, and depth of discharge.
If a battery is used as a source in a circuit with a dynamic load, changes in the voltage across the
load will be produced proportional to the electronic resistance of the battery and other sources
of resistance in the circuit. If the peak load current is high enough or the electronic resistance
of the battery and the resistance between the source and the DUT is large, the voltage drop com-
promises the performance of the device.
This phenomenon occurs in TDMA and GSM cellular handsets where the magnitude of the
“ON/OFF” current during transmission varies by as much as a factor of 20. In the absence of
any filtering capacitance between the battery and the RF power amplifier, the handset will shut
off if the supply voltage is below the operating threshold for periods as short as several micro-
seconds.
Command
Description
SENS2:RANG 5
‘ Select 5A range.
SOUR2:VOLT 15
‘ Set output voltage to 15V.
SOUR2:CURR 0.75
‘ Set current limit to 750mA.
OUTP2 ON
‘ Turn output on.
SENS2:LINT:TEDG RISING
‘ Select rising trigger edge to initiate mea-
surement.
SENS2:LINT:TLEV 0.1
‘ Set trigger level to 100mA.
SENS2:LINT:TIME:AUTO
‘ Set integration time automatically for single
pulse.
SENS2:FUNC “LINT”
‘ Select long integration function.
READ2?
‘ Trigger and return one reading and reading
shown on display.
