AN74 SiL INK PS-EVB U SER ’ S G UIDE 1. Introduction The SiLinkPS-EVB is a system power supply board that provides all the necessary supply voltages for a variety of Silicon Laboratories’ ProSLIC and silicon DAA evaluation boards. When used with an appropriate ac/ dc wall adapter, the SiLinkPS-EVB can provide up to 25 W of total output power. Table 1 lists some typical voltages and currents at the power supply outputs. Table 1. Power Supply Specifications Input/Output Voltage Current Power VIN 9–15 V 2.5 A 22–37 W VBRNG –96 V 100 mA 9.6 W VBHI –52 V or –78 V 100 mA 5.2 W or 7.8 W VBLO –26 V 200 mA 5.2 W VDD 3.3 V/5 V 1A 3.3 W/5 W Any combination of outputs is possible as long as the simultaneous total power from all outputs does not exceed the maximum rated 25 W and can be sufficiently supported by the input power from the VIN. The SiLinkPS-EVB is designed with the same footprint as all ProSLIC evaluation board daughter cards High Voltage Battery Supply allowing it to be used in conjunction with multiple ProSLIC daughter cards to create a modular evaluation platform. The SiLinkPS-EVB circuit is based on two power supply controllers from Linear Technology that provide high efficiency and low bill-of-materials cost. Both circuits can be synchronized to the same switching frequency to reduce power supply switching noise. The outputs can be configured to support both internal and external ringing architectures by setting the provided jumpers to set the desired output voltages. Further modifications are possible to realize specific output voltage and current requirements provided the total output power does not exceed the rated maximum. Schematic capture and layout gerber files are available for integration into specific applications. Figure 1 illustrates a simplified block diagram of the SiLinkPS-EVB supply board. 2. Operating Instructions The SiLinkPS-EVB board should always be connected to the ProSLIC evaluation board platform prior to turning on the power supply. Plugging any ProSLIC board into a live high-voltage supply can permanently damage the ProSLIC ICs. The user should exercise caution when touching any part of the SiLinkPS-EVB because dangerous high voltages are present and can cause injury. Jumper Selection JP2, JP3, JP4 VBRNG VBHI VBLO VDC in VDD Low Voltage VDD Supply JP6 VDD on/off JP5 3.3 V/5 V Selector Figure 1. SiLinkPS-EVB Power Supply Simplified Block Diagram Rev. 0.2 8/03 Copyright © 2003 by Silicon Laboratories AN74-DS02 AN74 2.1. High-Voltage Battery Supply The schematic for this power circuit is illustrated in Figure 3 on page 4. The LTC3704 dc-dc controller IC is used to drive an external MOSFET and a multi-tap transformer to create four equal high-voltage negative outputs, VNEG (See Table 2), from the dc input supply. Only one output is regulated via close-loop feedback. The other three outputs are cross-regulated to the first output via the transformer ratio. The LTC3704’s negative feedback input eliminates inverting circuitry when creating negative outputs from a positive input. The six-winding 1:1 ratio transformer is configured in a manner that minimizes the need for multiple highvoltage output filter capacitors. JP7 jumper. The voltage on the VBHI and VBRNG outputs can be programmed by moving the jumper settings on JP2, JP3, and JP4. Table 2 provides several popular configurations and the required jumper settings. 2.3. Frequency Adjustment The LTC3704 can be configured to run at switching frequencies from 50 kHz to 1 MHz allowing flexibility to choose the optimal efficiency/cost point for each specific application. Resistor R18 programs the switching frequency according to the characteristic curve shown in Figure 2. 1000 2.2. VNEG Voltage Adjustment RT (kΩ) The transformer, T1, has four secondary windings, each producing an equal negative voltage, VNEG. These four windings are connected in series through the diode rectifying circuits to produce four negative voltage potentials with voltage levels equal to multiples from 1 to 4 of the VNEG magnitude. Any adjustment made to the VNEG has a direct effect on the voltage levels on all negative outputs. Resistor R23 can be modified to realize custom output voltages as defined in the following equation. 100 10 VNEG = (1.23 x R23/R22) + 1.23 The SiLinkPS-EVB is shipped with R23 = 33.2 k and R22 = 1.65 k for VNEG equal to 26 V. 0 100 200 300 400 500 600 700 800 900 1000 FREQUENCY (kHz) Figure 2. Timing Resistor R18 Value The VBLO is normally used for off-hook state and its voltage level can be programmed by the setting on the Table 2. Popular Application Configurations and Jumper Settings Dual ProSLIC Part Number Si3211/Si3212 Si3220/Si3232 Si3225 PK-PK Ringing VBRNG Amplitude VBHI VBLO JP2 JP3 JP4 JP7 75 V — –78 V 3xVNEG –26 V VNEG 2–3 2–3 1–2 2–3 90 V –104 V 4xVNEG — –26 V VNEG 1–2 — — 2–3 N/A (external) — –52 V 2xVNEG –26 V VNEG 2–3 — 2–3 2–3 Rev. 0.2 2 AN74 2.4. Low Voltage VDD Supply 2.6. Initialization Steps The low-voltage supply provides a switchable 3.3 V or 5 V output with a 1 A maximum load current. The schematic for this power supply circuit is illustrated in Figure 4 on page 5. The LT1375 IC integrated 1.5 A bipolar switching transistor and current-sensing circuitry eliminate external power transistors and sense resistors and provide a high-efficiency VDD supply in a small footprint. The switching frequency is internally fixed at 500 kHz and can be synchronized to higher frequencies up to 1 MHz when a higher frequency signal (above 550 kHz) is provided on the SYNC pin. Table 3 provides the jumper settings for selecting a 3.3 V or 5 V output as well as for disconnecting the VDD supply altogether. 1. Configure all jumpers according to the application requirements. Table 3. VDD Supply Jumper Settings Function VDD output enable 3.3 V/5 V configuration JP5 JP6 Comments — 1–2 VDD connected — 2–3 VDD disconnected 1–2 — 5 V selected 2–3 — 3.3 V selected 2.5. Frequency Synchronization The LTC3704 is wired as a clock master device to provide its switching frequency to the SYNC pin on the LT1375 IC. To synchronize the frequency between the two power circuits, R18 needs to be adjusted to set the LTC3704 switching frequency at or above 550 kHz. The LT1375 IC operates at its internal fixed 500 kHz and is only synchronized with the LTC3704 frequency when it senses the frequency on the SYNC pin going above 550 kHz. The SiLinkPS-EVB power circuits are designed to operate safely with switching frequency on the LTC3704 ranging from 200 kHz to 1 MHz. 2. (Optional) Plug in the input power source and measure all outputs to verify correct settings. 3. Unplug input power source. 4. Assemble all ProSLIC daughter cards. 5. Plug in the input power source. 2.7. Cost-Optimized Design The negative high-voltage circuit can be reduced for cost optimization. The four equal VNEG outputs in series arrangement provide some discrete voltage adjustments to the outputs but require additional rectifying diode circuits and increase cost. Figure 6 on page 8 illustrates a lost-optimized design with two negative outputs. The first secondary winding produces a negative voltage according to the VNEG equation described in the previous section to produce the VBLO voltage. The other three secondary windings are connected in series to produce a negative voltage with an amplitude of 3 x VNEG. This output is connected in series with the VBLO output to generate VBHI output with a voltage level of 4 x VNEG. The use of the simplified secondary rectifying circuit, smaller transformer, and switching MOSFET lower the component costs and also reduce the maximum output power of the negative high-voltage circuit to 13 W. Rev. 0.2 3 100pF C20 R22 1.65k, 1% R18 31.6k, 1% 3 1 J1 CONN HEADER 2x2/SM R13 13k C14 .001uF CONN SOCKET 2x2/SM JS2 R21 82k C22 .001uF 4 2 3 1 4 2 3 1 3 1 2 4 2 4 1 3 1 3 Gate IntVcc Vin Sense IntVcc R23 33.2k, 1% Mode/Sync Gnd Freq NFB Ith Run (Farside) JP1 5 4 3 2 1 6 7 8 9 10 2 4 6 8 10 JS4 1 3 5 7 9 C23 .001uF 1 3 5 7 9 VBHI VBLO VDD DC_Input_Diode C21 4.7uF, 10V IntVcc CONN SOCKET 5x2 2 4 6 8 10 U2 LTC3704EMS R17 4.7 C24 330uF 35V DC_Input_Diode D3 CMR3-02 Turn-on at 9.9V Turn-off at 9.1V R14 82k DC_Input R19 47 1 Gate JS1 3 2 R20 .02, 1% 8 5 9 4 T1C JS5 D12 B1100B D11 B1100B -52Vdc D8 B1100B -78Vdc D5 B1100B -104Vdc CONN SOCKET 5x2 CONN SOCKET 5x2 10 3 C15 1uF, 25V T1D C11 1uF, 25V T1E C19 4.7uF, 50V Q2 IRL540NS 7 C8 1uF, 25V T1F T1A VP5 T1B 6 VBRNG C17 10uF, 25V -25Vdc C12 10uF, 25V C9 10uF, 25V C5 10uF, 25V R15 10k R11 10k R9 10k R4 10k 9 7 5 3 1 JS3 10 8 6 4 2 10 8 6 4 2 CONN SOCKET 5x2 9 7 5 3 1 -52V -78V C13 1uF, 100V C10 1uF, 100V Post-regulator Q1 VBLO -25V -50V R6 10k 1 2 3 JP7 JP7 2-3 2-1 D10 47V D9 47V R8 4.7k FZT953CT Figure 3. High-Voltage Negative Battery Supply C18 0.1uF 11 2 12 1 10 8 6 4 2 10 8 6 4 2 9 7 5 3 1 9 7 5 3 1 1 3 5 7 9 1 3 5 7 9 Rev. 0.2 2 4 6 8 10 4 2 4 6 8 10 R25 0 L2 10uH R7 100k -52V -78V VBLO C25 4.7uF, 50V C7 1uF, 100V -96V 1 2 3 JP4 1 2 3 JP3 1 2 3 JP2 JP3 X 2-3 1-2 VBHI VBRNG JP2 -96V 1-2 n/c 2-3 VBHI -52V -78V -96V VBRNG JP4 2-3 1-2 1-2 AN74 Gate DC_Input_Diode C1 22uF, 6.3V R26 10k D2 1N4148 C3 1uF, 25V C2 0.1uF L1 15uH, 1.8A R27 10k Vc FB GND SYNC Rev. 0.2 8 7 6 5 Figure 4. Low-Voltage VDD Supply R28 10k LT1375CS8 BOOST Vin Vsw SHDN U1 C26 100pF 1 2 3 4 D1 B1100B C4 4.7nF R2 31.6k, 1% R1 11.5k, 1% 1 2 3 JP6 VDD on VDD off VDD 1 2 3 JP5 5V 1-2 3.3V 2-3 R3 16.2k, 1% VDD 5V or 3.3V 1A Max AN74 5 Figure 5. PS Board Silkscreen AN74 6 Rev. 0.2 AN74 3. Si Link PS–EVB Bill of Materials Re fe re nce C1 C2 C3,C8,C11,C15 C4 C5,C9,C12,C17 C7,C10,C13 C22,C14 C18 C16, C19 C20,C26 C21 C23 C24 D2 D3 D1,D5,D8,D11,D12 D9,D10 JP1 JP2,JP3,JP4,JP5,JP6,JP7 JS1,JS3,JS4,JS5 JS2 J1 L1 L2 Q1 Q2 R1 R2 R3 R4,R9,R11,R15,R26,R27,R28 R6 R7 R8 R13 R21,R14 R17 R18 R19 R20 R22 R23 R25 T1 U1 U2 De scription 22uF, 6.3V 0.1uF, 10V 1uF, 25V 4.7nF, 10V 10uF, 25V 1uF, 100V .001uF, 25V 0.1uF, 35V 4.7uF, 50V 100pF, 25V 4.7uF, 10V .001uF, 25V 330uF, 35V 1N4148 ES3A/B B1100B 47V Zener CONN HEADER 2x2/SM HEADER 3X1 CONN SOCKET 5x2 CONN SOCKET 2x2/SM CONN PW R 2-P 15uH, 1.8A 10uH FZT953CT IRL540NS 11.5k , 1% 31.6k 16.2k 10k 10k 100k 4.7k 13k 82k 4.7 120k 47 15m 1.65k 33.2k 0 VP5 LT1375CS8 LTC3704EMS Rev. 0.2 Pa rt Num be r Ma nufa cture r TMK432BJ106KM Taiyo Yuden 18121C105KAT9A United Chemi-con 08055C102KAT AVX 08053C104KAT AVX C5750X7R1H475K TDK 08055A101KAT AVX LMK316BJ475 Taiyo Yuden ES3A/B B160B Diodes, Inc. Diodes, Inc. Diodes, Inc. TSM-102-02-T-DV 2303-6111TN SSQ-1-05-24-F-D SSM-102-L-DV-TR ADC-002-1 UP1B-150 CTX32CT-100 FZT953CT IRL540NS Samtec 3M Samtec Samtec Adam Tech Coiltronics Coiltronics Zetex Int. Rectifier LRC1206-R015K VPH5-0155 LT1375CS8 LTC3704CMS IRC Coiltronics LTC LTC 7 9 7 5 3 1 JS1 10 8 6 4 2 3 1 10 8 6 4 2 R22 1.87k, 1% 36k = 500kHz 20k = 1MHz R18 36k CONN SOCKET 5x2 9 7 5 3 1 R21 82k C22 .01uF 680pF C20 R13 16k C14 .001uF 10~15Vdc Input 3 1 D3 B340 5 4 3 2 1 Gate IntVcc Vin Sense IntVcc 6 7 8 9 10 JS3 C21 4.7uF, 10V IntVcc VBRNG R17 4.7 C24 330uF 35V CONN SOCKET 2x2 CONN SOCKET 5x2 JS2 R23 34.8k, 1% Mode/Sync Gnd Freq NFB Ith Run U2 LTC3704EMS Turn-on at 9V Turn-off at 8.2V R14 82k DC_Input 4 2 4 2 3 1 3 1 10 8 6 4 2 10 8 6 4 2 9 7 5 3 1 C18 0.1uF 1 6 2 8 3 Q2 Si4480DY R20 7 1 3 5 7 9 10 3 9 4 8 5 7 6 1 3 5 7 9 C17 10uF, 25V C5 2.2uF, 100V 2 4 6 8 10 2 4 6 8 10 JS4 In Proto: R23 = 20.5k R22 = 1.1k C5 = 2 x 1uF / 100V in parallel R4 = 3 x 10k in series Q2 is upside-down D12 B1100B D4 ES1D CONN SOCKET 5x2 C19 4.7uF, 50V T1C T1D T1F VP5 T1E T1B .015, 5% VBHI VBLO DC_Input_Diode VDD 4 5 11 2 12 1 T1: 10uH T1A R15 10k R4 30k JS5 C16 10uF, 25V L2 10uH L2 and C16 optional for lower output noise. CONN SOCKET 5x2 -24Vdc -96Vdc Figure 6. Cost-Optimized Dual Output Battery Supply 9 7 5 3 1 1 3 5 7 9 1 3 5 7 9 Rev. 0.2 2 4 6 8 10 8 2 4 6 8 10 JP1 VBLO VBHI AN74 AN74 4. Cost-Optimized Dual Output Battery Supply Bill of Materials Reference C18 C5 C22, C14 C16*, C17 C19 C20 C21 C24 D3 D4 D12 L2* Q2 R4 R13 R21, R14 R15 R17 R18 R20 R22 R23 T1 U2 Description 0.1 F, 25 V, X7R 2.2 F, 100 V, X7R 1 nF, 25 V, X7R 10 F, 25 V, X5R 4.7 F, 50 V, X7R 100 pF, 50 V, NP0 4.7 F, 10 V, X5R 330 F, 35 V 40 V, 3 A 200 V, 1 A 100 V, 1 A Shottky 10 H, 300 mA 80 V 30 k, 5%, 0.25 W 16 k, 5%, 0.1 W 82 k, 5%, 0.1 W 10 k, 5%, 0.1 W 4.7 , 5%, 0.1 W 36 k, 5%, 0.1 W 15 m, 5%, 0.25 W 1.87 k, 1%, 0.1 W 34.8 k, 1%, 0.1 W 10 H Switching Regulator Part Number Manufacturer 08053C104KAT AVX C5750X7R2A225M TDK TMK432BJ106KM UMK325F475KH 08055A101KAT LMK316BJ475 35CV330AX B340 ES1D B1100B CTX32CT-470 Si4480DY Taiyo Yuden Taiyo Yuden AVX Taiyo Yuden Sanyo Diodes, Inc. Diodes, Inc. Diodes, Inc. Coiltronics Vishay SP36-0100-10 LTC3704EMS Transpower LTC Note: * Optional components used to reduce output noise if necessary. Rev. 0.2 9 AN74 DOCUMENT CHANGE LIST Revision 0.1 to Revision 0.2 New power supply schematics Updated 10 Figures 3, 4, and 5. Updated document to support two levels of VBATL voltage. Rev. 0.2 AN74 NOTES: Rev. 0.2 11 Smart. Connected. Energy-Friendly Products Quality www.silabs.com/products www.silabs.com/quality Support and Community community.silabs.com Disclaimer Silicon Laboratories intends to provide customers with the latest, accurate, and in-depth documentation of all peripherals and modules available for system and software implementers using or intending to use the Silicon Laboratories products. Characterization data, available modules and peripherals, memory sizes and memory addresses refer to each specific device, and "Typical" parameters provided can and do vary in different applications. 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