How to measure regulator output delay time by using DGT

Introduction

In evaluation of regulator circuit, There is a case to evaluate output delay time.

You can measure output delay time with high precision by measuring regulator output with high precision using DGT(Digitizer) in CloudTesting(TM) Service.

This document explains how to measure output delay time of regulator using CloudTesting(TM) Service.

Case

As an example, this document explains how to measure “tDelay” of following picture.

Required IPs

Analog Output Verification IP This is an algorithm IP that measures by synchronizing voltage output from a target to be measured to the pattern program.
It sets a limit value for each measure value to judge Pass/Fail.

Generic Search IP

This is an algorithm IP that searches Pass/Fail transition point by result of specifying the measurement item and the variable using in its item and changing the variable value. It sets the limit and judges Pass/Fail transition point.

Measurement Procedure

1. Define a variable

Define a variable that changes at Generic Search IP.

Setting example

In the following example, define a variable named “tDelay”.

2. Make the testitem that measures output voltage by Analog Output Verification IP

In Analog Output Verification IP, The voltage sampling point is set by pattern address.

Acquire the voltage of analog output at pattern address [n+1] after that the trigger channel turned to High(starting voltage of analog output).

Setting example

1.set acquiring point by pattern address

Set output voltage acquiring point by pattern address in DGT Conditon tab of Analog Output Verification IP like a following example.

2.Specify rise-up timing by expression

For changing rise-up-timing by Generic Search IP,
Set rise-up-timing of the trigger channel by expressions as following picture.

3.Set the voltage range of judgement

Set the judgement range of the output voltage as following picture.

3. Measure measure output delay time by Generic Search IP

Generic Search IP searches Pass/Fail changing point of the specified measurement item by changing the value of variable in that item.

It measures output delay time like a following example.

  1. Shift forward the rise-up-timing of the trigger channel with Generic Search IP.

  2. The output voltage changes according to the changing of rise-up-timing of the trigger channel. The value of rise-up-timing of the trigger channel will be the time from when the trigger channel becames High to when the output voltage reaches a desired voltage.

Setting example

1.Set the condition

As shown below, Set the variable to be changed with Condition tab.

2.Excute the test

Execute the test.

3.Confirmation of measurement result

Confirm measurement result in data log.

Caution

  • In the case of performing output delay time measurement in Flow Execution, it does not have to perform “the test item that measures the voltage” as below.

Updated at
January 01, 2017