OPENLPPOL-EVB Silicon Labs

Open-Loop POL-EVB OPEN-LOOP POL EVALUATION BOARD USERS GUIDE 1. Kit Contents The Open Loop Point of Load (POL) Evaluation Board contains the following items: Open-Loop Evaluation Board featuring: Si8234 ISOdriver Si8512 AC Current Sensor Si8540 DC Current Sensor 1.1. Hardware Overview The Open Loop POL Evaluation Board implements a single-phase POL (an architecture similar to that found in switch-mode power supplies, motor control, inverters, and ballast lighting) whose switching frequency can be varied from 100 to 500 kHz. Its duty cycle can be varied from 20 percent to 80 percent. Figure 1 illustrates a high- level schematic overview. This variability provides a convenient means to fully evaluate the various products featured on the board. The Open Loop POL evaluation board shown in Figure 2 uses Silicon Laboratories Si8234 ISOdriver to drive the high-side and low-side FETs. It uses two Si8512 ac current sensors to monitor the switching currents in the high-side and low-side FETs respectively. The board also uses the Si8540 dc current sensor to monitor the dc current being delivered to the load. Refer to the Si85xx, Si823x, and Si854x family data sheets for more information concerning their operation. +12 V Si8512 High Side AC Current Sensor HS FET Si8540 DC Current PWM Si8234 Sensor Source ISODriver LS FET Si8512 Low Side AC Current Sensor Figure 1. Open Loop POL High-Level Schematic Rev. 0.3 9/10 Copyright 2010 by Silicon Laboratories Open-Loop POL-EVBOpen-Loop POL-EVB Figure 2. Open Loop POL Evaluation Board 2. Required Equipment The following equipment is required: 1 digital multi-meter 2 multi-meter test leads (black and red) 1 oscilloscope (Tektronix TDS 2024B or equivalent) 1 BNC splitter 5 BNC cables 1 dc power supply (HP6024A, 15 V dc, 05 A or equivalent) 2 banana to banana wires (black and red) 1 electronic load simulator (Kikusui PLZ164WA or equivalent) 1 Agilent 33220A 20 MHz function/arbitrary wave generator or equivalent Open-Loop POL Evaluation Board (board under test) Open-Loop POL Evaluation Board Users Guide (this document) 2 Rev. 0.3