Keithley unveils portable battery/charger tester
Keithley Instruments has introduced the Model 2308 portable battery/charger simulator, a dual-channel battery- and charger-simulating power supply for testing portable battery-powered devices
The Model 2308 is optimised for ultra-fast test times, allowing manufacturers to lower their cost of test.
Unlike conventional power supplies, the Model 2308 features fast recovery even when load currents change by a factor of 10 or greater.
If the load pulse is too short, the conventional power supply may never return to its stable output level during the pulse.
Even with long test leads, the Model 2308 maintains a stable output voltage in response to pulse loads with a transient voltage drop of under 90mV and a transient recovery time of under 35us.
This is critical for mobile phones with pulsed-mode operation.
Maintaining a constant output voltage ensures that the device under test (DUT) does not turn off during testing and that it draws sufficient power to operate properly.
An excessive overshoot voltage transient can damage components leading to premature device failures.
The 2308 also saves test time by making fast load current measurements.
An optimised command structure minimises range changes and current measurement times for production testing.
The 2308 can change range and make a power line cycle measurement in 27ms.
With four current ranges spanning 5A to 5mA, and resolutions from 100uA to 0.1uA, test engineers can monitor small changes in load current measurements for tight quality control on production runs.
Load currents, even pulses as narrow as 50us, are measured with integrating A/D technology.
With a sampling A/D, information between samples is lost, which reduces the accuracy of the overall measurement.
In addition, the lower noise inherent in integrating A/D converters generates the most stable current readings.
In production applications, the Model 2308 employs four-wire sourcing and remote sensing for precision voltage sourcing, even when the DUT cannot be close to the power supply.
The source accuracy enables a Model 2308 channel to act as a calibration source for battery monitoring circuitry used in mobile phones and other portable devices.
With two channels packed into one half-rack instrument, one channel can simulate the battery and the other can simulate a charger.
In addition, each channel can act as a load as well as a source.
Thus, the battery channel can sink current to simulate a discharged battery so that the DUT's charger control circuit can be tested.
In addition, the Model 2308 can simulate the performance of a battery by simulating the battery's internal resistance with a programmable output resistance.
Similar to a battery, the Model 2308's output resistance can change while voltage is being sourced to simulate the increase in the battery's internal resistance as the battery discharges.
The 2308 contains two power supply channels, a DVM for voltage measurements on the DUT and digital control ports for relay control.
It is well-suited for design and test of low-power, battery-operated devices, such as 3G mobile phones, smart phones, MP3 players, Bluetooth headsets, PDAs, and portable GPS receivers.
Publication date: 25.09.2008