AN4396 Application note STEVAL-ISV021V1, energy harvesting system based on SPV1050, PV panel and battery Domenico Ragonese Introduction The STEVAL-ISV021V1 is a demonstration kit which consists of a complete energy harvesting module based on the SPV1050 ULP energy harvester and battery charger, having the purpose to show the electrical performance of the power converter and many other fundamental electrical quantities related to the overall system. The SPV1050 power manager is configured as a buck-boost converter, fitting the electrical characteristics of the mounted PV panel and battery. A power monitoring board along with a software GUI are used to monitor and to graph both of the PV panel and battery voltage and current, and system performances, like MPPT accuracy and conversion efficiency. The STEVAL-ISV021V1 represents the standalone harvesting module that can be interfaced with a wireless sensor node to provide the microcontroller, transmitter and sensors with the energy scavenged and stored into the battery. Furthermore, the STEVAL-ISV021V1 harvesting module embeds an extension connector to interface and to monitor of some of the SPV1050 input and output signals through a microcontroller based board. The complete STEVAL-ISV021V1 kit is shown in Figure 1. Figure 1. Power monitoring board (left) and harvesting module (right), top view June 2014 DocID025514 Rev 1 1/19 www.st.com Contents AN4396 Contents 1 Schematic and bill of material . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 2 Harvesting module layout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 3 Harvesting module connectors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 4 Jumpers and switches . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 5 Harvesting module and power monitoring board . . . . . . . . . . . . . . . . 14 6 Revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 2/19 DocID025514 Rev 1 AN4396 1 Schematic and bill of material Schematic and bill of material The schematic, bill of material and gerber files can be downloaded from the Design resources tab of the STEVAL-ISV021V1 product folder on www.st.com. DocID025514 Rev 1 3/19 19 Schematic and bill of material 4/19 Figure 2. Harvesting module schematic 86% (;7(51$/ 6833/< $0%,(17 /,*+7 6(1625 8 $0%,(17B/,*+7 8 $'287 *1' 1& ,1 67/4 +$59(67(5 $1' %$77(5< 0$1$*(5 *1' - 9 6725( & X) 6725( 6285&( 6% N 5 N2KP &21$ &1 6% N - $0%,(17B/,*+7B3,1 6833/<B6)+ & X) 73 - 9B86% - 393$1(/ / 6285&( X+ 39 73 - ,1B/9 9%$77BRXW ,1B/9 3*1' 8 8 9EDWW 0LFUR86% /B+9 3*1' - ,1B+9 033 & X) 6725( 033 0336(7 0335() 6*1' /'2B(1 033 73 5PSSV N2KP 73 033B5() 73 033B6(7 639 6*1' 8 & & X) X) %$77B&+* Q) 5LQ 73 893 5HRF 02KP &XYS Q) (2& 5RXW 02KP /'2B(1 %$77B&211 /'2 73 /'2 & Q) 73 (2& 6*1' (;7(16,21 %$77B&+* 6: /'2B(1 73 & Q) 893 /'2B9 /'2B9 6725( 5XYS 02KP 02KP 32:(5 021,725,1* %7 9 6*1' /'2B(1 & 73 6725( %$77 &21) /'2 /'2 %$77B&211 DocID025514 Rev 1 5PSS 02KP /'2B9 6: 6/,'(6367 - 6285&( 39 9EDWW 9%$77BRXW 6833/<B6)+ $0%,(17B/,*+7B3,1 $0%,(17B/,*+7 6285&( 39 9EDWW 9%$77BRXW 6833/<B6)+ $0%,(17B/,*+7B3,1 $0%,(17B/,*+7 6725( /'2B9 6: 6: 6/,'(6367 6725( - AN4396 /'2B9 /'2B9 %$77B&211 %$77B&+* $0 Sect. Item Qty. 1 1 Battery Ref. Part/value BT1 Support for Li-Ion battery 2 1 J6 SMD jumper 3 2 U3 Flexible PV panel 1 J4 SMD jumper SMD Pitch 100 mils Pitch 100 mils Keystone Manufacturer code More information 3008 SMD FCI 95293-101-03LF This jumper allows the connection of the STORE pin to the voltage regulator U4 in case the external sampling is OFF SMD SANYO AM-1801 2 PV panels connected in series 95293-101-03LF This jumper disconnects the PV panel U3 in case an alternative supply is required and connected to CN1 SMD FCI Supply DocID025514 Rev 1 5 Tolerance Voltage Technol. Watt Package Manufacturer (%) current info. AN4396 Table 1. Harvesting module BOM 6 1 J5 3-way switch Pitch 100 mils SMD FCI 95293-101-03LF This jumper allows the connection of the source to the harvester U1 in case the external sampling is OFF 7 1 CN1 2-way conn. Pitch 100 mils SMD FCI 95293-101-03LF Input connector for external PV panel or TEG Schematic and bill of material 5/19 Sect. Item Qty. Ref. Part/value Tolerance Voltage Technol. Watt Package Manufacturer (%) current info. MPPT section 1 U2 SPV1050 9 1 C6 1 µF 15% 10 1 Rmpp 10 M 1% 11 1 Rmpps 680 k 1% 12 1 Rin 3 M 0.01 13 1 C34 10 nF 15% 14 LDO1 DocID025514 Rev 1 Harvester/DC-DC controller section 8 1 L1 22 µH 15 1 SW1 3-way switch 16 1 C5 100 nF LDO2 17 1 SW2 3-way switch 18 1 C4 100 nF Manufacturer code Harvester and thin film battery manager ST 25 V 16 V X5R 0603 Murata GRM188R61E105KA12D Input capacitance 0.1 0603 VISHAY CRCW060310M0FKEA Resistor partitioning for MPP track 0.1 0603 TE Connectivity CRG0603F680K Resistor partitioning for MPP setting 0603 VISHAY CRCW06033M00FKEA Input resistor partitioning 0603 Murata GRM188R71C103KA01D Voltage sampling time constant capacitance Coilcraft LPS4018-223ML_ LPS5010-223ML_ XFL2006-223ME_ DC-DC inductor Close 1 - 2, LDO1 is disabled Close 2 - 3, LDO1 controlled by external signal X7R 20% 10% 10% 6.3 V 6.3 V More information Pitch 100 mils SMD FCI 95293-101-04LF X5R 0402 AVX 04026D104KAT2A Pitch 100 mils SMD FCI 95293-101-04LF X5R 0402 AVX 04026D104KAT2A Schematic and bill of material 6/19 Table 1. Harvesting module BOM (continued) Close 1 - 2, LDO2 is disabled Close 2 - 3, LDO2 controlled by external signal AN4396 Sect. Item Qty. Ref. Part/value Tolerance Voltage Technol. Watt Package Manufacturer (%) current info. Manufacturer code More information Battery management section 2 C9, C10 47 µF 20% 6.3 V X5R 0805 KEMET C0805C476M9PAC7800 Capacitor on STORE net 21 1 Cuvp 470 nF 15% 10 V X5R 0603 Murata GRM188R71A474KA61D UVP voltage sampling delay time constant capacitance 22 1 Ruvp 6.8 M 1% 0603 VISHAY CRCW06036M80FKEA 23 1 Reoc 0.75 M 1% 0603 VISHAY CRCW0603750KFKEA 24 1 Rout 3 M 1% 0603 VISHAY CRCW06033M00FKEA Ambient light 25 1 U7 SFH5711 SMD OSRAM SFH 5711 26 1 R12 80 k 0603 VISHAY CRCW060382K0FKEA 27 1 J7 SMD jumper SMD FCI 95293-101-03LF External supply from USB DocID025514 Rev 1 19 28 1 U8 STLQ50CR SOT3235L ST STLQ50C-R 29 1 SB49 5.36 k 0.1 0603 Panasonic ERA3AEB5361V 30 1 SB50 2.05 k ±1% 0.1 0603 VISHAY CRCW06032K05FKEA 31 2 C14, C15 1 µF 15% X5R 0603 Murata GRM188R61E105KA12D 33 1 J23 SMD jumper Pitch 100 mils SMD FCI 95293-101-03LF 1% 0.1 Pitch 100 mils VEOC = 4.15 V VUVP = 3.75 V Ambient light sensor: place on the same solder side of the PV panel (U3) Disable charging from USB 7/19 Schematic and bill of material 25 V AN4396 Table 1. Harvesting module BOM (continued) Sect. Item Qty. Ref. Part/value External connections DocID025514 Rev 1 Spacers + nuts 34 1 J28 Micro-USB 35 1 J25 16-pin conn. 36 1 J27 16-pin conn. 37 4 Screw support Tolerance Voltage Technol. Watt Package Manufacturer (%) current info. Manufacturer code More information SMD Molex 47346-0001 External charge from USB 2.54 mm SDM Samtec SMH-108-02-G-D Connector for future extensions 2.54 mm SMD Samtec SMH-108-02-G-D Connector for power monitoring board RS 325-687 and 525-701 Schematic and bill of material 8/19 Table 1. Harvesting module BOM (continued) AN4396 AN4396 2 Harvesting module layout Harvesting module layout Figure 3 and Figure 4 show the component placement and the layout (top and bottom views) of the harvesting module. Figure 3. Harvesting module - top view Figure 4. Harvesting module - bottom view DocID025514 Rev 1 9/19 19 Harvesting module layout AN4396 In order to ensure a proper noise rejection that could impact the SPV1050 device performance, the following indications must be followed in the PCB routing: 10/19 The exposed pad and the pins PGND and GND must be connected to the same ground plane. The capacitor on the STORE pin must be placed as closest as possible to the related pin. The capacitors on the LDO1 and LDO2 pins must be placed as closest as possible to the related pins. DocID025514 Rev 1 AN4396 3 Harvesting module connectors Harvesting module connectors The STEVAL-ISV021V1 provides a set of connectors for the input sources which are described below: CN1 (2-pin connector) This connector is provided to supply the SPV1050 device by a supply source alternative to the on-board PV panel. Table 2. CN1 connector CN1 pin number Signal 1 2 SOURCE + SOURCE - The J4 must be open before an external source is connected to the CN1. For the proper selection of the external source, please refer to the datasheet of the SPV1050 device. J25 (16-pin extension connector). It can be used to connect the harvesting module to an external load such as a wireless sensor node module. Table 3. J25 connector J25 pin number 1-2 3-4 5-6 SPV1050 LDO1_EN LDO2_EN BATT_CHG pin signal CONTROL CONTROL 7-8 9 - 10 11 - 12 13 - 16 BATT_CONN LDO2 LDO1 GND – LDO1_EN CONTROL (input): it provides the connection to an external signal that controls the LDO1_EN pin. In this case the SW1 must be left open. If the LDO1 is not used, the LDO1_EN pin has to be connected to ground. – LDO2_EN CONTROL (input): it provides the connection to an external signal that controls the LDO2_EN pin. In this case the SW2 must be left open. If the LDO2 is not used, the LDO2_EN pin has to be connected to ground. – BATT_CHG (output): battery charge status pin. This is an open drain pin that has to be pulled up by a resistor (10 M typical) to VSTORE voltage rail. – BATT_CONN (output): battery connection status pin. This is an open drain pin that has to be pulled up by a resistor (10 M typical) to VSTORE voltage rail. – LDO2: LDO2 (3.3 V) output voltage pin. – LDO1: LDO1 (1.8 V) output voltage pin. – GND: ground pin of the extension board. J27 (16-pin monitoring connector) It provides the connection to the power monitoring board. DocID025514 Rev 1 11/19 19 Harvesting module connectors AN4396 Table 4. J27 connector J27 pin number 1-2 Signal 12/19 3-4 SOURCE PV+ 5-6 7-8 Vbatt+ VBATT_OUT 9 - 10 SUPPLY_ SFH5711 11 - 12 13 - 14 AMBIENT_ AMBIENT_ LIGHT_PIN LIGHT 15 - 16 GND – SOURCE, PV+: Harvesting source current sensing pin. If the power monitoring board is used, then the jumper J5 must be left open; otherwise pins 1 and 2 of the J5 must be shorted. – VBATT+, VBATT_OUT: Battery current sensing pin. If the power monitoring board is used, then the jumper J6 must be left open; otherwise pins 1 and 2 of the J6 must be shorted. – SUPPLY_SFH5711: Power supply of the ambient light sensor pin (placed on the top side of the board). – AMBIENT_LIGHT, AMBIENT_LIGHT_PIN: Ambient light current sensing pin. If the power monitoring board is used, then the jumper J7 must be left open. – GND: Ground pin. DocID025514 Rev 1 AN4396 4 Jumpers and switches Jumpers and switches Table 5. J4 jumper J4 Function CLOSE 1 - 2: harvesting board supplied by the on-board PV panel OPEN 1 - 2: enables an alternative source from the CN1 Table 6. J5 jumper J5 Function CLOSE 1 - 2: bypasses power monitoring sense and supply directly the SPV1050 OPEN 1 - 2: power monitoring enabled from the power monitoring board Table 7. J6 jumper J6 CLOSE 1 - 2: bypasses power monitoring sense and connects the battery to the BATT Function pin OPEN 1 - 2: enables sensing from the monitoring board Table 8. J7 jumper J7 Function CLOSE 1 - 2: not used OPEN 1 - 2: enables ambient light sensing from the monitoring board Table 9. J23 jumper J23 Function CLOSE 1 - 2: STORE pin supplied by the USB cable OPEN 1 - 2: STORE pin supplied by the energy harvesting source Table 10. SW1 and SW2 SW1 Function SW2 CLOSE 1-3: LDO1 DISABLED CLOSE 1-3: LDO2 DISABLED CLOSE 2-3: LDO1 ENABLED CLOSE 2-3: LDO2 ENABLED FLOATING: EXTERNAL CONTROL BY J25 FLOATING: EXTERNAL CONTROL BY J25 DocID025514 Rev 1 13/19 19 Harvesting module and power monitoring board 5 AN4396 Harvesting module and power monitoring board The harvesting module can be used both: as a standalone device or with the power monitoring board. In the standalone mode, leave the CN1 open and connect the jumpers as described below: Close pins 2 - 3 of the J4 and close pins 1 - 2 of the J5 in order to supply the SPV1050 device by the on-board PV panel. Close pins 1 - 3 of the J6 in order to connect the on-board battery. Figure 5. Jumper configuration for harvester module in stand-alone mode It is possible to monitor the system behavior and efficiency by following the listed steps: Place a voltmeter between pins 1 - 2 of the CN1 (VIN) Replace the short on the J5 by an ammeter (IIN) Place a voltmeter between the TP16 and TP8 (VBATT) Replace the short on the J6 by an ammeter (IBATT) The STEVAL-ISV021V1 kit includes the power monitoring board, and the related GUI which runs on the Windows® XP and Windows 7 OSs. The power monitoring board and the related GUI allow a quick and intuitive way to monitor the system performances. 14/19 DocID025514 Rev 1 AN4396 Harvesting module and power monitoring board Before to connect the harvester module to the power monitoring board, set the jumpers as described below: Close pins 2 - 3 of the J4 in order to supply the SPV1050 device by the on-board PV panel Close pins 2 - 3 of the J5 in order to allow the power monitoring to sense the input voltage and current. Close pins 2 - 3 of the J6 in order to allow the power monitoring to sense the battery voltage and current. Close pins 2 - 3 of the J7 in order to allow the power monitoring to sense the ambient light on the PV panel. Figure 6. Jumper configuration for harvester module connected to power monitoring board DocID025514 Rev 1 15/19 19 Harvesting module and power monitoring board AN4396 Figure 7 shows the connection of the harvesting module and the power monitoring board of the STEVAL-ISV021V1 kit. Figure 7. Power monitoring board (left) and energy harvesting module (right) The power monitoring board allows to measure up to three voltage-current pairs when connected to a generic DUT. This board can acquire up to 12800 samples per second when a single channel is active. For multi-channel acquisition the available bandwidth is split among the three channels. Two channels can acquire currents in the range 1 A - 15 mA, while the third one works in the range 1 A - 1 mA. This board can be used as a general purpose measurement board, and in this case is a part of the STEVAL-ISV021V1 kit. The ambient light irradiation, the input supply operating points (the input voltage and current of the harvested source) and the output stage operating points (the battery voltage and current) are sampled. The sampled parameters can be displayed by the GUI once the monitoring board is connected to a PC or laptop through the dedicated USB cable. Note: Please note, that connecting the harvesting module to the power monitoring board, while this is not powered through the USB cable, causes current draining from the battery, and hence potential damages. The GUI is arranged in four selectable “tabs”: 16/19 Configuration: allowing the setup of the power monitoring board. Data visualization: not used with the STEVAL-ISV021V1. Power visualization: displaying the power sink by the load eventually connected to the “extension” connector J25. Efficiency: displaying the system performances both in terms of MPPT accuracy and power efficiency. DocID025514 Rev 1 AN4396 Harvesting module and power monitoring board Just as an example, Figure 8 the efficiency tab: The GUI will show the actual PV panel curve according to the current ambient light conditions. On the PV panel curve the green dot indicates the real working point, while the blue dot indicates the maximum power point. The table on the top right side of the screen shows the main system parameters and performances. A detailed description of the GUI is available in the “Software user manual” - UM1752. Figure 8. STEVAL-ISV021V1 “efficiency” tab DocID025514 Rev 1 17/19 19 Revision history 6 AN4396 Revision history Table 11. Document revision history 18/19 Date Revision 03-Jun-2014 1 Changes Initial release. DocID025514 Rev 1 AN4396 Please Read Carefully: Information in this document is provided solely in connection with ST products. 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