Agilent HP AN 1246 Application Note free download

File name HP AN 1246 Application Note.pdf

Agilent AN 1246 Pulsed Characterization of Power Semiconductors Using Electronic Loads Application Note Electronic Load Improves Power Electronic Loads Semiconductor Measurements An electronic load eliminates the self- An electronic load (see figure) employs a power MOSFET as an electronically variable load that dis- heating problems associated with sipates power. The electronic load senses MOSFET current (Iin), then amplifies it, compares it with measuring the on-state voltage drop a reference, and feeds back the output of an error amplifier to the MOSFET gate. This forms a and transconductance (or current closed-loop current control system. Therefore, the electronic load's input current (IIN) is propor- gain) of power semiconductors. tional to the control reference input. Input current, IIN, loads the DC power source (battery or power supply). On-state voltage drop and transcon- ductance (or current gain) of power Given a fixed control reference, the load acts as a series current regulator. If the control reference FETs, BJTs, and IGBTs are tempera- is proportional to the load input voltage (VIN), the load behaves like a high quality power resistor. Some load manufacturers also offer a constant voltage regulation mode in which the load ture dependent, but are typically behaves like a power zener diode. specified at 25