The PMIC Load and Line Transient Response Plugin

Figure 1. Test setup for the Load and Line Transients Measurements

The plugin requires the following four instrument types. For each type the PMIC specifications will dictate the model that works best. However, provided it has remote programming capability, the instrument can be ‘mapped’ to be used by the plugin. The four instruments are:

• Source Measure Unit (SMU) or Power Supply to power the input voltage rail of the PMIC and to allow measurement of the input voltage and input current. If the voltage drop between the SMU terminals and the Device Under Test (DUT) input voltage rails is a concern, then an SMU with four wire measurement capability is desirable.
• Pattern Generation/Acquisition Device for configuring the relevant mode of the DUT. The plugin allows a variety of digital protocols including any custom synchronous protocol.
• Source Measure Unit (SMU) or Electronic Load in combination with a suitable fixed load such as a decade resistance box for purposes of establishing the desired load current at the output terminals of the PMIC. The same load may be used for measuring the load current and load voltage etc. There are some applications such as those involving Fully Integrated Voltage Regulators (FIVR) where it is not practical to use an electronic load because the load is some other device than the DUT. In this case, the Pattern Generation/Acquisition device can have a port assigned for configuring the device that is behaving as the load so the desired load profile can be set up.
• An oscilloscope or combination of oscilloscopes to capture the different channel traces that represent the transient response on different output pins.
• For current measurements, oscilloscope current probes are needed on the different current paths being measured.

Figure 2. Front Panel of the Load Transient plugin

The PMIC Load Transient Response plugin takes advantage of the Hardware Abstraction Layer functionality built in to SIVA framework which makes it easy for a test engineer to use measuring instruments from any vendor. The HAL concept is illustrated in Figure 3.

Figure 3. The Hardware Abstraction Layer (HAL) built into SIVA makes it possible for the PMIC Load Transient Response plugin to work with instruments of the same type from any manufacturer.

The Hardware Abstraction Layer encapsulates the instrument driver/API and presents the measuring instrument from any manufacturer appear as a generic device. The front panel controls provided by the HAL allows the test engineer to set up measurement limits and ranges easily and with minimal time.

Figure 4. Test Settings for the Load Transient plugin

The Test Parameters tab contains input fields for setting the range over which the different load and line current/voltage parameters are to be varied and the number of steps.
 

What advantages does using the PMIC Load Line Transient Response SIVA Plugin afford the user over building his or her own test code for Load and Line Transients?
  

• Provides immediate GUI look and feel with quick access to high resolution transient scope shot measurements for overshoot, undershoot, settling time, ripple etc.
• Selectable current or input voltage transition settings
• Avoids user having to tweak oscilloscope settings such as voltage and current scales since the plugin will automatically start with a lower timing and voltage resolution and go finer and finer until a nicely centered high resolution scope shot capturing the transient signature is obtained.
• Access to DUT registers or DUT Bit Fields in an off the shelf manner, which can be exercised during the running of the test or during an automation sweep running in NI TestStand also.
• Input parameter saving, retrieval, management and underlying state machine and UI capabilities are provided by the SIVA framework itself. For any further functionality, clicking on ‘Edit Code’ exits the runtime environment on the Plugin Debug Panel and enters LabVIEW coding mode.
• Off-the-shelf data logging facility with default access to spreadsheet logs and features such as auto-incremented labeling and timestamps already provided Additional data logging plugins can be developed using a template as desired.
• An integrated sequencer operator interface that leverages the powerful NI TestStand for running higher level sweeps.

 
Also available as a separately sold add-on to the PMIC Line and Load Transients Plugin is DIVE, a waveform tagging, learning and analysis tool that uses Machine Learning Models to simplify the waveform analysis for typical PMICs. One can train DIVE to classify the waveform scope-shots from the PMIC output terminals as NORMAL/ANOMALOUS/DEFECT1 etc.Some thematic diagrams and screenshots are shown below.

Figure 5. Workflow and Capabilities of DIVE.

Figure 6. PMIC Switching regulator waveform analysis in progress using DIVE.