STEVAL-ISV006V1 STMicroelectronics, STEVAL-ISV006V1 Datasheet

Page 1

... The SPV1040 guarantees the safety of the application device or of the converter itself by stopping the PWM switching in the case of an overcurrent or overtemperature condition. The IC integrates an 80 mΩ N-channel MOSFET power switch and a 120 mΩ P-channel MOSFET synchronous rectifier. February 2011 STEVAL-ISV006V1: solar battery charger Doc ID 18265 Rev 1 AN3319 Application note using the SPV1040 www ...

Page 2

Contents Contents 1 Application overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ...

Page 3

... Figure 9. STEVAL-ISV006V1 top view . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 Figure 10. STEVAL-ISV006V1 bottom view . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 Figure 11. STEVAL-ISV006V1 schematic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 Figure 12. STEVAL-ISV006V1 Iout filter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 Figure 13. STEVAL-ISV006V1 PCB top view . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 Figure 14. STEVAL-ISV006V1 PCB bottom view . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 Figure 15. SPV1040 output parallel connection Figure 16. SPV1040 output series connection Doc ID 18265 Rev 1 List of figures 3/24 ...

Page 4

Application overview 1 Application overview Figure 1 shows the typical architecture of a boost converter based solar battery charger: Figure 1. Boost application schematic The SPV1040 adapts the characteristics of load to those of panel. In fact panel ...

Page 5

AN3319 2 Boost switching application A step-up (or boost) converter is a switching DC-DC converter able to generate an output voltage higher than (or at least equal to) the input voltage. Referring to Figure square waveform generated by a PWM ...

Page 6

Boost switching application Figure 4. Inductor current in discontinuous mode Obviously the efficiency is normally higher in CM. Inductance and switching frequency (F the system working in CM, the rule below should be followed:   2 Vout ...

Page 7

AN3319 3 SPV1040 description The following is a quick overview of SPV1040 functions, features, and operating modes. Figure 5. Typical application schematic using the SPV1040 The SPV1040 acts as an impedance adapter ...

Page 8

SPV1040 description Figure 7. MPPT working principle Figure 7 shows the logical sequence followed by the device which proceeds for successive approximations in the search for the MPP. This method is called “Perturb and Observe”. The diagram shows that a ...

Page 9

AN3319 The duty cycle set by the MPPT algorithm can be overwritten if one of the following is triggered: Overcurrent protection (OVC), peak current on low side switch ≥ 1.7 A ● Overtemperature protection (OVT), internal temperature ≥ 155 °C ...

Page 10

... Figure 9. STEVAL-ISV006V1 top view Figure 10. STEVAL-ISV006V1 bottom view STEVAL-ISV006V1 has been designed to work with a 200 mW PV panel (Vmp=1 V, Imp=200 mA) and to regulate the output voltage order to guarantee the reliability of the application, Vout max. must be regulated at 4 DCM is triggered. Two trimmers allow to regulate the voltage on the V flexibility level either at PV panel or at battery side ...

Page 11

... AN3319 5 Schematic and bill of material Figure 11. STEVAL-ISV006V1 schematic L1 PV SHUT XSHUT R GND MPP SET MPP-SET C IN1 PV- Table 1 shows the list of external components used in the demonstration board. Table 1. BOM Component Name (alternate label) CIN1 Input capacitor Voltage sensing C4 capacitor Voltage sensing C2 capacitor ...

Page 12

Schematic and bill of material Table 1. BOM (continued) Component Name (alternate label) SuperCap Super capacitor PV panel Polycrystalline solar cell 12/24 Value Supplier 220 mF Panasonic 175 mW NBSZGD 175 mA Doc ID 18265 Rev 1 AN3319 ...

Page 13

AN3319 6 External component selection SPV1040 requires a set of external components and their proper selection guarantees both the best chip functionality and system efficiency. Input voltage capacitor Cin1 is the input capacitor connected to the input rail in order ...

Page 14

External component selection Input voltage sensing capacitor C4 is placed in parallel to R4 and as close as possible to the V V voltage. MPP-SET However, V MPP-SET input voltage variations. It means that the time constant [(R3//R4)*C4] must be ...

Page 15

AN3319 Irms is the self rising temperature of the inductor, affecting the nominal inductance value. In particular, the inductance decreases with Irms and the temperature increases consequence the inductor current peak can reach or surpass 1.7 A. Inductor ...

Page 16

... Iout _ max The triangular waveform of the current and noise may cause unexpected triggering of the 50 mV threshold. This can be avoided with a filter such as the one shown below: Figure 12. STEVAL-ISV006V1 Iout filter VOUT VOUT ICTRL_PLUS ICTRL_MINUS Suggested values are kΩ µF ...

Page 17

AN3319 Output protection diode D is placed in parallel to the output load. Its role is to protect the devices in case a PV OUT cell providing Imp > 0 connected when very low load is connected. In ...

Page 18

... Layout 7 Layout Figure 13. STEVAL-ISV006V1 PCB top view Figure 14. STEVAL-ISV006V1 PCB bottom view Layout guidelines PCB layout is very important in order to minimize voltage and current ripple, high frequency resonance problems, and electromagnetic interference essential to keep the paths where the high switching current circulates as small as possible in order to reduce radiation and resonance problems ...

Page 19

AN3319 Appendix A SPV1040 parallel and series connection Output pins of many SPV1040s can be connected either in parallel or in series. In both cases the output power (Pout) depends on light irradiation of each panel, on application efficiency, and ...

Page 20

SPV1040 parallel and series connection According to the light irradiation on each panel and to the system efficiency (η), the output power results   Pout Pout 1 Pout Poutx =   Voutx * Ioutx Pinx =   Vinx ...

Page 21

AN3319 Therefore:   1 Voutx = Vout 3 For example, assuming Pout = 3 W and Vout = 12 V, then Voutx = 4 V. Lower irradiation for one panel, for example on panel 2, causes lower output power, so ...

Page 22

SPV1040 parallel and series connection Example 2: Panel 2 has 50 % irradiation of panels 1 and 3:   Pout 2 * Pout   Pout 1 Pout   ...

Page 23

AN3319 Revision history Table 2. Document revision history Date 02-Feb-2011 Revision 1 Initial release. Doc ID 18265 Rev 1 Revision history Changes 23/24 ...

Page 24

... Information in this document is provided solely in connection with ST products. STMicroelectronics NV and its subsidiaries (“ST”) reserve the right to make changes, corrections, modifications or improvements, to this document, and the products and services described herein at any time, without notice. All ST products are sold pursuant to ST’s terms and conditions of sale. ...