The Keithley 2304A 100W High-Speed Precision Readback Power Supply provides both voltage control and power consumption monitoring for automated testing of portable, battery-operated devices. These power supply is optimized for testing battery-operated, wireless communication devices such as cellular phones that undergo substantial load changes for very short time intervals. The2304A exhibits outstanding voltage stability during pulse load changes and can simultaneously measure load currents, even if they are short pulses. In addition, this power supply can sink current and thus, take on the characteristics of a discharged, rechargeable battery for testing chargers and charger-control circuitry.

5A Output Capacity

The 2304A can supply 5A at 20V to serve the peak pulse loading requirements of battery-operated devices. In both instruments, the maximum current of 5A can be delivered continuously; it can also supply up to 20V DC.

Fast Response to Load Changes

Keithley's High Speed Power Supplies are designed to simulate the current drive capacity of a battery. The power supplies simulate a battery's response during a large load change by minimizing the maximum drop in voltage and recovering to within 100mV of the original voltage in 40µs or less.

When a portable device such as a cellular phone switches from standby mode to the full power mode of operation, the current draw on the power supply can change by as much as 1000%. While a battery's voltage will decrease by the value of the voltage drop across the battery's low internal resistance, a conventional power supply will have a significant voltage drop (more than one volt) and take milliseconds to recover to the original voltage level. For portable devices that operate at full power only for short intervals, the full power event is over before a conventional power supply can recover. For example, cellular phones designed in accordance with the GSM cellular phone standard transmit and receive information in 576µs pulses. If the power supply used to test them cannot recover quickly enough, the performance of the deviceunder - test will be compromised by the power supply. If the power supply voltage drops below the threshold of the phone's low-battery detection circuitry for a sufficient amount of time, the phone will turn off during testing, giving a false indication of a failed device.

The 2304A's fast transient response to large load changes will enable test engineers to test their portable products properly and eliminate false failures due to conventional power supplies with slow response times. In this way, the power supply ensures maximum production throughput when testing portable devices.

Fast Measurements for Power Consumption Analysis

As manufacturers of portable devices strive to extend battery life and the length of time between recharges, power consumption has become an important performance indicator. Therefore, in production testing, accurate peak power and average power measurements are critical. These measurements are complicated by the fact that wireless telecommunication devices draw full load current in short pulses. The 2304A's pulse readback measurement mode makes it possible to capture peak and average values on pulses as short as 60µs. This allows the power supply to power a device-under-test and determine its current consumption to qualify the device for its specified power consumption.

In addition to making measurements on short pulses, the 2304A power supply can measure a current pulse peak or a current pulse train that is as long as 833ms. For random pulse trains that have periods longer than 833ms, the power supply has a special, elongated integration mode that can make an average current measurement on up to 60s of data.

Accurate Low-Current Measurement

The 2304A is well-suited for making fast, accurate measurements of sleep and standby mode currents because is is based on Keithley's expertise in low-current measurement technologies. With 100nA resolution, the power supplies offer the precision needed to monitor the low sleep mode currents in today's products and in future products. They can also measure these low-currents with 0.2% basic accuracy.

High-Current Sinking Capacity

The 2404A can act as an electronic load and sink as much as 3A, so it can simulate a discharged rechargeable battery. Therefore, it can be used to verify the performance of a portable device's charger. The power supply's current dissipation capacity allows it to test even high-current fast chargers.

Independent Digital Voltmeter Inputs

While many programmable power supplies offer output readback capabilities, Keithley's power supplies are the only instruments available that also offer a set of DVM inputs. These inputs allow the 2304A to measure signals from 0 to +20V anywhere in the test system with the same rated accuracy as the voltage readback. The DVM and the power source can operate simultaneously. For many applications, the power supply's built-in DVM eliminates the expense and space that a separate voltage measurement instrument would require.