High Amplitude Arbitrary/Function Generator Simplifies Measurement in Automotive, Semiconductor, Scientific and Industrial Applications Application Note
Figure 1. Measurement setup with external amplifier.
A number of electronic design applications require stimuli with amplitudes that exceed the capabilities of most arbitrary/function generators available in the market today. These applications include power semiconductors, such as MOSFETs and IGBTs widely used in automotive electronic systems and switching power supplies, amplifiers for gas chromatography and mass spectroscopy detectors, and others in science and industry.
This application note describes the conventional approach of generating high amplitude signals with an external amplifier. It then discusses typical applications and shows the benefits of using a novel arbitrary/function generator with integrated high amplitude stage. Applications described in this note include measuring the timing and switching characteristics of power semiconductors for automotive applications and the characterization of amplifiers for gas chromatography detectors.
Commonly, arbitrary/function generators provide amplitudes of up to 10 Vpp into 50 Ω loads and 20 Vpp into open circuits. The devices mentioned above often operate over an input range that is twice as large. Until now, testing these devices over their full operating range commonly required an amplifier to boost the signal provided by a standard generator. This increased the complexity of the test set-up, created uncertainty about the effective amplitude at the amplifier output, and added equipment cost.
The Conventional Approach
Figure 1 shows the typical measurement setup of a standard arbitrary/function generator with additional amplifier to boost the amplitude to the required level. The generator output is connected to the amplifier input. Some amplifiers allow the inputs and/or outputs to be configured to match different source and/or load impedances. Commonly, boost amplifiers do not feature a display so that the effective output amplitude must be monitored with an oscilloscope or other measurement device. This adds to the complexity of the measurement setup and requires additional time, especially when amplitude levels need to be adjusted and verified before and during the test.