PI3110-01-EVAL1 Vicor

USER GUIDE UG:301 PI31xx-xx-EVAL1 ZVS Isolated DC-DC Converter Evaluation Board Chris Swartz Principal Applications Engineer Contents Page Introduction Introduction 1 The PI31xx-xx-EVAL1 evaluation board allows the user to test the basic operating principles of the PI31xx Series PI31xx series of high-density DC-DC power converters and experience the performance and value of this solution compared to alternate conventional solutions. Each evaluation board is populated with Product Description 2 the components that could be used in a final design. It is not designed or intended to be used in Board Connections 2 end-product applications. Please read this document prior to the connection of test equipment and refer to the product data sheet for device specifications, descriptions and characteristics. Remember to Thermal Considerations 4 follow good lab safety practices and use safety glasses at all times. Ordering Information 14 The PI31xx-xx-EVAL1 is configured to support one single input and one single output. Each board offers pin-strap options for trimming the output voltage up and down, turning the converter on and off and adding EMI system Y capacitors. Additional parts are included to compensate for line impedance associated with long leads from the bench power supply to the converter. Additional component footprints are made available to allow the user to test different design configurations that may be required to meet their end needs. Kelvin-type test points are included to allow for easy and convenient connections of testing instruments for evaluation of efficiency, line/load regulation and transient response. A low-impedance oscilloscope connection using a Johnson jack is included for ripple measurement and evaluation of the output voltage during transient events. Each demo board is equipped with a heat sink to allow high-power operation with a small amount of air flow and to allow operation of the board over various temperature extremes. Figure 1 PI31xx-xx-EVAL1 Evaluation Board UG:301 Page 1PI31xx Series Product Description The PI31xx operates over a wide-range input, delivering 50 or 60W output power depending on the individual model number. The PI31xx series is available in a space-saving surface-mountable 0.87 x 0.65 x 0.265in Power-System-in-a-Package (PSiP), achieving ~50% space reduction versus alternative solutions. The switching frequency of 900kHz allows for small input and output filter components which further reduces the total size and cost of the overall system solution. The output voltage is sensed and fed back to the internal controller using a proprietary isolated magnetic feedback scheme which allows for high bandwidth and good common-mode noise immunity. The PI31xx series requires no external feedback compensation and offers a total solution with a minimum number of external components. A rich feature set is offered, including +10%, 20% output voltage trim capability (depending on the model number), remote enable, overvoltage protection, adjustable soft start, overcurrent protection with auto restart to protect against both short-circuit and overload, and over and under input voltage lockout. A unique temperature monitor and protection circuit is included that provides an analog voltage proportional to the internal die temperature, as well as overtemperature shut down, restart and overtemperature-fault alarm signal. Board Connections 1. Connect Test Equipment a. Connect the input DC power supply to the target board as shown in Figure 6. The negative terminal should be wired to IN and the positive terminal should connect to the positive terminal of the DMM wired as a DC Ammeter. Be sure that the proper sized wires are used to allow minimum voltage drop for a maximum input current of up to 4A. Use ring lugs mated to the included fasteners on the evaluation board. If your input power supply has remote sense capability, it can be wired to the INN and INP test points if desired. Connect the positive terminal of the DMM to the +IN lug on the evaluation board. b. Connect the primary side DMM (for measuring the input voltage) to INN and INP respectively. c. Connect the oscilloscope as shown in Figure 6 if you are planning to measure both primary and secondary signals at the same time. If you do not have an isolated differential amplifier, it is important to note that simultaneous measurement of both primary and secondary referenced signals using an oscilloscope with a grounded chassis is not recommended, as it will short circuit the primary to secondary isolation barrier. Floating the oscilloscope is also not recommended due to the large capacitance introduced by this long standing practice. The best practice is to use an isolated differential amplifier or use an oscilloscope with isolated channels. That is, the input returns are isolated from each other and earth ground. d. Connect the output DC DMM to the test points OUTN and OUTP. These test points are done in a Kelvin type manner so that they have no high current flowing in them. e. Connect the DC Load to the output lugs OUT+ and OUT. It is critical for this connection to be low inductance. UG:301 Page 2