MIC9131 Evaluation Board Micrel MIC9131 Evaluation Board High Voltage, High Speed Telecom DC to DC Controller General Description Operation Operation requires a 36-72 V 2.5Amp dc power supply. Converter current limit is set at 22 Amps. The optimum orientation of the converter is to have the high power component side facing upwards for better exposure to forced air. Layout/PCB Page 8 displays the PCB layout. The inner layer provides shielding of the control circuitry from the noisy signals associated with the high power components on the topside of the board. The MIC9131 1/4 brick evaluation board is a 48 Volt input/ 3.3 Volt, 20 Amp output, DC-DC converter. The actual current rating depends upon the ambient air temperature and the level of forced air applied to the module. A peak current mode, resonant reset, forward converter, with syncronous recitification topology is used. The design uses Micrel’s low voltage operational amplifiers MIC860 and 1.2Volt reference LM4041 for the secondary opto isolated feedback and compensation circuitry. Included in the design is the option to select two different methods for the syncronous gate drive. The module is manufactured with a direct drive scheme which is easily converted to the gate charge retention scheme. Remote sense pins compensate for load cable voltage drop and a primary side enable pin is included. Specifications Parameter Conditions min typ max Units 36 48 72 V Turn-On Voltage Threshold 32.2 33.8 35.5 V Turn-OffVoltage Threshold 28.3 30 31.6 V Input Characteristics Operating Input Voltage Range Maximum Input Current 2.3 A Output Characteristics Output Voltage Setpoint Output Current Range 3.268 3.301 3.334 V See Note 1 0 20 A Room temperature, no airflow 0 15 A Current Limit Inception 22 A Ripple 50 mV 1 mV Load Regulation No load to full load Line Regulation 20A 0.5 mV Efficiency 10A, 48V 90 % 20A, 48V 85 % 300 kHz Feature Characteristics Switching Frequency On/Off Control Voltage On-State Voltage 1 1.6 2.2 V Off-State Voltage 0.85 1.45 2.05 V Micrel, Inc. • 1849 Fortune Drive • San Jose, CA 95131 • USA • tel + 1 (408) 944-0800 • fax + 1 (408) 944-0970 • http://www.micrel.com November 2001 1 MIC9131 Evaluation Board MIC9131 Evaluation Board Micrel Transient Response Self Driven Syncronous Drive Scheme Output Voltage Response to a step change in load current (100% - 75% - 100%) VIN = 36V IOUT = 20A VDS Q1 (50V/div) (100mV/div) VGS Q3/Q5 (10V/div) 20A - 15A Load VIN = 48V TIME (1µs/div) TIME (400µs/div) Self Driven Syncronous Rectifier Drive Scheme Self Driven Syncronous Drive Scheme VIN = 12V IOUT = 20A VDS Q1 (50V/div) VDS Q1 (50V/div) VGS Q3/Q5 (10V/div) VGS Q3/Q5 (10V/div) VIN = 48V IOUT = 20A TIME (1µs/div) TIME (1µs/div) Efficiency vs. Load Current Current Limit Characteristic 0.95 48V 0.85 0.8 OUTPUT VOLTAGE (V) EFFICIENCY (%) 0.9 3.5 72V 36V 0.75 0.7 0.65 0.6 0 2 4 6 8 10 12 14 16 18 20 LOAD CURRENT (A) MIC9131 Evaluation Board 3 2.5 2 1.5 1 0.5 0 0 2 5 10 15 20 LOAD CURRENT (A) 25 November 2001 MIC9131 Evaluation Board Micrel Conversion to and Advantages of the Gate Charge Retention Syncronous Reticfier Scheme Conversion to the gate charge retention can be achieved by removing the Jumpers JA and JB and installing components CR9, CR10, CR11 and Q6. On some boards JA and JB may actually be circuit board traces that must be cut prior to installing the required components. See layout on page 8. The gate charge retention drive scheme eliminates a number of problems associated with the self driven syncronous gate driv scheme. First of all the scheme removes the need for additional schottky diode, D1, reducing cost and board area. Additionally, when using the gate charge retention scheme multiple converters can be paralleled for n+1 redundantcy. This is not possible with the self driven scheme. Also in the self driven scheme as the converter approaches a short circuit condition, the current diverted through D1 becomes excessive. Gate Charge Retention Scheme Gate Charge Retention Scheme VIN = 48V IOUT = 20A VGS Q3/Q5 (10V/div) VGS (10V/div) VDS Q1 (50V/div) VDS (50V/div) VIN = 72V IOUT = 20A TIME (1µs/div) TIME (1µs/div) Gate Charge Retention Scheme Enable and Turn-On Characteristics VIN = 36V IOUT = 20A VGS Q3/Q5 (10V/div) Output Voltage (1V/div) VDS Q1 (50V/div) Enable (10V/div) VIN = 48V IOUT = 20A TIME (1µs/div) TIME (4ms/div) Gate Charge Retention Scheme Efficiency 90 72V 48V EFFICIENCY (%) 85 80 36V 75 70 65 60 0 2 4 6 8 10 12 14 16 18 20 LOAD CURRENT (A) November 2001 3 MIC9131 Evaluation Board MIC9131 Evaluation Board Micrel Output Noise and Ripple The figures below display the output ripple and noise associated with the output at 48 Volts input and 20 Amp load. This measurement was taken directly across the output capacitors using a ring and tip probe configuration. The first figure was taken with an additional .0047uF common noise capacitor from the output ground to the input ground. Future revisions will include this capacitor on the board. Output Voltage Ripple with common mode cap (4.7nF) Output Voltage Ripple with no external common mode cap (4.7nF) Input = 48VDC IOUT = 20A (20mV/div) (20mV/div) Input 48VDC IOUT = 20A TIME (1µs/div) TIME (1µs/div) MIC9131 Evaluation Board 4 November 2001 November 2001 5 Enable J2 EN J3 VIN return C3 1µF/ 100V R6 37.4k R5 1M C18 0.1µF C4 1µF/ 100V C16 10nF/ 16V R9 560k C15 270pF R22 10k R10 2.61k R20 49k C19 10pF VIN 36V to 72V DC J1 VIN+ R28 20k R19 10k 8 7 6 5 4 3 2 1 CPWR FB COMP SYNC OSC RBIAS VCC LINE VBIAS EN AGND SS UVLO ISNS PGND OUT U1 MIC9131 C11 1µF/25V C13 0.1µF/ 16V CR2 SMAZ18 CR5 1n4148 C21 1000pF C17 22pF R23 15k CR7 1n4148 C7 10nF/ 16V R21 1k CR6 1n4148 R2 10Ω R4 16Ω R25 33k CR13 MM5Z15T1 L2 22µH CR4 ES1D C9 1000pF CR3 ES1D Figure 1. Evaluation Board Schematic 9 10 11 12 13 14 15 16 R24 7.68k CR12 1n4148 R16 1k T2 31334R R3 10Ω V– R11 511Ω R12 100Ω Q7 2N2222 U2 PS2703-1 Q1 SUD20N90 T1 19:3 JA C8 0.1µF CR10 CR9 Q2/Q4 SI4884 JB D1 B530C R13 4.02k C10 N/A D3 R27 33k C23 3.3nF CR11 C20 22nF R26 22k MIC860 Q3/Q5 SI4884 C14 10µF 25V C12 1000pF Q6 L1 1.5µH@ 24A CR8 ES1D C5 0.1µF MIC860 D2 C6 0.1µF R1 10k C22 N/A R18 10Ω C1 220µF/ 10V R17 10Ω R7 5.9k R15 10k R8 10k R19 10k C2 100µF/ 6.3V U5 LM4041 S– V– V+ S+ MIC9131 Evaluation Board Micrel MIC9131 Evaluation Board MIC9131 Evaluation Board Micrel Bill Of Material Item Part Number C2 GRM44-130 X5R 107K6.3 muRata 100uF/6.3V X5 1 C1 594D227X0010D2T Vishay Sprague 220uF/10V 1 C3,C4 GRM44-1 X7R 105K muRata 1.0uF 100V 2 C5,C6,C8, C13,C18 VJ0603Y104KXXAB Vishay Vitramon 0.1uF/25V 5 C20 VJ0603Y223KXXAB Vishay Vitramon 22nF/25V X7R 1 C7,C16 GRM39X7R103M16 muRata 10nF/16V X7R 2 C9 VJ1206Y102KXCAB GHM1525X7R102K Vishay Vitramon muRata 100pF/500V 1 C11 GGRM42-6 X7R105K25 muRata 1uF 25V 1 C12,C21 VJ0603102KXXAB Vishay Vitramon 1000pF/25V 1 C14 GRM235Y5V106Z25 muRata 10uF/25V Y5V 1 C15 GRM39COG271F10 muRata 270pF/10V 1 C23 VJ0603Y332KXXMT Vishay Vitramon 3.3nF/25V 1 C17 VJ0603Y220KXXAB Vishay Victramon 22pF/25V 1 C19 VJ0603Y100KXXAB VishayVictramon 10pF/25V 1 CR13 MMSZ15T1 ON SEMI 15V 0.5W 1 Diodes, inc. 18V 1W 3 CR2,D2,D3 SMAZ18 Manufacturer Description Qty D1 B530C Diodes, inc. 5A 30 V Shottky 1 CR5,CR6, CR7,CR12 LL4148 DL4148 Diodes, inc. Micro component 500mW switching diode 4 CR3,CR4, CR8 ES1D ES1D Diodes inc. Micro component 1 Amp 200V ultra fast 3 T1 HM00-01604A TTI8136-C BI Technologies Transpower Technologies power transformer 1 T2 31334R MIDCOM current sense transformer 1 L1 HM00-01605A TTI8135-C BI Technologies Transpower Technologies Output Inductor 1 L2 CDRH5D18-220NC Sumida inc. Snubber Inductor 1 U1 MIC9131BM Micrel Inc. Control IC 1 U2 PS2703-1 CTR “K” NEC. Corp Opto Isolator 1 U3,U4 MIC860BM5 Micrel Inc. Opmp 2 U5 LM4041DIM-1.2 Micrel Inc. 1.2V reference 1 R11,R16, R21 CRCW06031001FRT1 Vishay Dale 1k,1%,1/16W 3 R11 CRCW06031001FRT1 Vishay Dale 511, 1% 1/16W 1 R2,R3, R17,R18 CRCW060310R0FRT1 Vishay Dale 10, 1%, 1/16W 4 R4 CRCW060316R0FRT1 Vishay Dale 16, 1%, 1/16W 1 R5 CRCW06031004FRT1 Vishay Dale 1M,1%,1/16W 1 R6 CRCW06033742FRT1 Vishay Dale 37.4k, 1%, 1/16W 1 R25,R27 CRCW06033022JRT1 Vishay Dale 33k, 5%, 1/16W 2 R20 CRCW06034902FRT1 Vishay Dale 49k, 1%, 1/16W 1 R9 CRCW06035603JRT1 Vishay Dale 560k, 5%, 1/16W 1 R10 CRCW06032611FRT1 Vishay Dale 2.61k, 1%, 1/16W 1 R7 CRCW06035901FRT1 Vishay Dale 5.9k, 1%, 1/16W 1 R12 CRCW06032000FRT1 Vishay Dale 100, 1%, 1/16W 1 R13 CRCW06034021FRT1 Vishay Dale 4.02k, 1%, 1/16W 1 R1,R8,R14, CRCW06031002FRT1 R15,R19, R22 Vishay Dale 10k, 1%,1/16W 6 MIC9131 Evaluation Board 6 November 2001 MIC9131 Evaluation Board Item Micrel Part Number Manufacturer Description Qty R16 CRCW06032212FRT1 Vishay Dale 22.1k, 1/16W, 1% 1 R23 CRCW06031502FRT1 Vishay Dale 15k, 1/16W,1% 1 R28 CRCW06032002FRT1 Vishay Dale 20k, 1/16W,1% 1 R24 CRCW06037681FRT1 Vishay Dale 7.68k, 1/16W,1% 1 JA, JB CRCW06030000FRT1 Vishay Dale 0 Ohm 2 Q1 SUD20N90 Siliconix 200V 90mΩ MOSFET 1 Q2,Q3, Q4,Q5 SI4884DY Vishay Siliconix 30V 10mΩ MOSFET 4 Q7 MMBT2222LT1 On SEMI NPN Transistor 1 J4,J8 1213-680-6 Zierick Surface Mount Pins 2 Vin+, Vin-, EN,S+, S- 81-500-6 Zierick Surface Mount Pins 5 Gate Charge Retention Option Bill of Materials (with JA and JB removed or cut) Item Manufacturer Description CR9,CR10, LL4148 CR11 DL4148 Part Number Diodes, inc. Micro component 500mW switching diode 3 Q6 On SEMI 20V 750mA 1 MGSF1N02LT1 Qty Manufacturer, Phone; website BI Technologies, (714) 447-2759; www.bitechnologies.com Diodes Inc., (805) 446-4800; www.diodes.com International Rectifier, (925) 455-8888 , (310)-322-3331; www.irf.com Micrel, Inc., (408) 944-0800; www.micrel.com Micro Commercial Component, (818) 701-4933 Mid Com, (605) 884-3561; www.midcom-inc.com muRata, (949) 916-4000; www.murata.com NEC Corp., (408) 243-2111; www.cel.com On Semiconductor, (800) 282-9855; www.onsemi.com Sumida, Inc, (510) 668-0660; www.sumida.com Transpower Technologies Inc., (775) 852-0140; www.trans-power.com Vishay Dale, (207) 324-4140; www.vishay.com Vishay Siliconix, (402) 563-6866; www.vishay.com Vishay Vitramon; www.vishay.com Zierick, (805) 379-0385; www.zierick.com November 2001 7 MIC9131 Evaluation Board MIC9131 Evaluation Board Micrel PCB Layout Information Figure 2a. Bottom Figure 2b. Bottom Silk Figure 2c. Top Figure 2d. Top Silk Figure 2e. Middle MICREL INC. 1849 FORTUNE DRIVE SAN JOSE, CA 95131 TEL + 1 (408) 944-0800 FAX + 1 (408) 944-0970 WEB USA http://www.micrel.com This information is believed to be accurate and reliable, however no responsibility is assumed by Micrel for its use nor for any infringement of patents or other rights of third parties resulting from its use. No license is granted by implication or otherwise under any patent or patent right of Micrel Inc. © 2001 Micrel Incorporated MIC9131 Evaluation Board 8 November 2001