® QP0-2-EVAL1 QUIETPOWER ™ Evaluation Board for QPO-2 Active Output Filter converter. The RSL resistor shown in Figure 4 of the product datasheet (not on the evaluation board) can be used to limit the correction current sourced from the Adjust+ circuit if needed during start-up preventing the converter from tripping OVP. The QPO-2-EVAL1 board provides an easy to use evaluation platform for testing the QPO-2 in a lowvoltage system. A filtered voltage range of 0.3 Vdc to 5.5 Vdc at output load currents up to 20A can be accomplished. A low current bias supply is required at the VAUX input in the range of 7 to 12 volts respectively to the output voltage range. The board comes with a QPO-2LZ and some essential external components pre-mounted. Please refer to the QPO- 2 datasheet for product details. Terminals for horizontal or vertical mounting are also provided. The user must mount and select component values for RHR, RSC, RSL and RSA based on their system needs. RHR is the headroom voltage setting resistor that will determine the voltage dropped across the QPO-2. The RSA resistor is for the slope-adjust option, which can be used to reduce the amount of voltage across the QPO-2 depending on load current. This reduced drop in voltage will result in a lower power loss across the QPO-2 providing greater efficiency but lower attenuation. An optional capacitor, CHR, can be added to extend the lowfrequency attenuation range of the QPO-2. RCP will preset the QPO-2’s reference voltage to a value close to the desired steady-state value. This reduces the time required for the QPO-2’s output to reach the steadystate output voltage. There is a provision for a startup circuit (Q1 RDLY D1 CDLY) if the initial headroom voltage needs to start from zero and increase gradually to the set headroom voltage. Remote sense components (CRS RRS), Figure 3 of the product datasheet, are mounted on the evaluation board. The RP resistor connects the QPO-2’s peak detection circuit to the input voltage rail. The peak detector will adapt the headroom voltage by adding half the peak-to-peak ripple voltage to the headroom. Internally, the QPO-2 has a 0.1uF capacitor on its peak detector pin that allows the user to filter out the converter’s ripple with an appropriate RP resistor value, disabling the peak detector. This filtering is enabled by using a low resistance value for RP, such as a zero ohm that comes pre-installed on the QPO-2 Eval board. When remote sensing is not used RSC is the current programming resistor that determines the current sourced by the QPO-2’s Adjust+ pin to drive the TRIM pin of a J1 VAUX QPO_IN QPO_OUT RCP RP 0 CRS 15 µF D1 J8 SENSE+ J5 ADJUST/SC MA111 RRS 51.1 QPO_OUT CDLY 0.1 µF Q1 IRLML6401 15 PEAK IN ADJUST 16 ADJUST+/19 GND 20 GND J4 GND VREF PEAKIN VAUX QPO OUT QPO OUT QPO OUT QPO OUT SC SET 1 17 8 7 6 5 QPO_OUT J2 QPO–OUT J3 QPO–OUT SCSET RSC 2 3 REFGND RDLY 20 K SLOPE ADJ QPO_IN QPO IN QPO IN QPO IN QPO IN QPO IN VREF/RUP 11 12 13 14 18 RCP/RDN 10 9 Low Voltage Start-up Circuit GND J7 QPO–IN VAUX J6 QPO–IN 4 J9 GND J10 GND RSA RHR CHR VREF Figure 1 - Evaluation board schematic Picor Corporation • www.picorpower.com QPO-2-EVAL1 Data Sheet Rev. 1.2 Page 1 of 2 Figure 2 - Figure 2 – Evaluation Board Layout * Note: Components Q1, D1, RDLY and CDLY are for an optional start-up circuit. Ordering Information Part Number Description QPO-2-EVAL1 Evaluation board for QPO-2LZ Vicor’s comprehensive line of power solutions includes high-density AC-DC & DC-DC modules and accessory components, fully configurable AC-DC & DC-DC power supplies, and complete custom power systems. Information furnished by Vicor is believed to be accurate and reliable. However, no responsibility is assumed by Vicor for its use. No license is granted by implication or otherwise under any patent or patent rights of Vicor. Vicor components are not designed to be used in applications, such as life support systems, wherein a failure or malfunction could result in injury or death. All sales are subject to Vicor’s Terms and Conditions of Sale, which are available upon request. Specifications are subject to change without notice. Vicor Corporation 25 Frontage Road, Andover, MA, USA 01810 Tel: 800-735-6200 Fax: 978-475-6715 Picor Corporation • www.picorpower.com • QPO-2-EVAL1 Data Sheet Email Vicor Express: [email protected] Technical Support: [email protected] P/N 30642 Rev. 1.2 4/09