SM3320-BATT-EV/NOPB National Semiconductor, SM3320-BATT-EV/NOPB Datasheet
SM3320-BATT-EV/NOPB
Specifications of SM3320-BATT-EV/NOPB
Related parts for SM3320-BATT-EV/NOPB
SM3320-BATT-EV/NOPB Summary of contents
Page 1
... SolarMagic™ SM3320- BATT-EV Charge Controller Reference Design Introduction The SM72442 MPPT digital controller and SM72295 photo- voltaic full bridge drivers are designed to control high efficien- cy DC/DC conversion used in photovoltaic applications. This application note will detail the usage of those devices in a battery charging application. The reference design is meant ...
Page 2
FIGURE 3. Charge Controller System Schematic, Part1 www.national.com 2 30138203 ...
Page 3
3 www.national.com ...
Page 4
Power Supply The following circuit shown in Figure 5 power supply rail required to properly bias the SM72295 gate DC/DC Converter The DC/DC converter stage is a step up/step down four switch converter as shown in Figure 6. This ...
Page 5
FIGURE 7. Buck Gate Drive Signals From SM72442 FIGURE 8. Switch Nodes in Buck Mode FIGURE 9. Boost Gate Drive Signals From SM72442 30138207 FIGURE 10. Switch Nodes in Boost Mode Programmable Modes/Gain Settings The voltage dividers for the output ...
Page 6
Start-Up Circuitry If the panel voltage is lower than the battery voltage, a start up circuit is required to force the duty cycle high enough to create a flow of current to the battery. Once current is estab- lished, the ...
Page 7
Output FET Disabling Q9 keep the topside output FET Q2 from turning on. The power will flow through the parallel diode D7 instead. This prevents the battery from discharging into the PV panels. Q2 can be disabled using the microcontroller ...
Page 8
Microcontroller Functions The charge profile is implemented in the current design using a PIC16F722 microcontroller. NORMAL OPERATION The following flowchart in Figure 18 the microcontroller needed to achieve the desired charging pattern. Modification to this flowchart can easily be done ...
Page 9
START-UP OPERATION At start-up, the microcontroller needs to assess the PV and battery voltage to verify proper connection and values. If the values are within the specified range (correct panel and battery voltage), the microcontroller enables the charge by releasing ...
Page 10
FUNCTION “check_lead_acid()” This function senses the battery voltage through the microcontroller’s A/D converter. The A/D conversion is need- ed because the current limiting circuit in hardware acts on the voltage sensing line of the SM72442. Therefore, when the system is ...
Page 11
FIGURE 20. Microcontroller Code Block Diagram Charging a Li-ion Battery Although this evaluation board was specifically designed for charging a lead-acid battery, it can be re-configured to ac- commodate the Li-ion chemistry battery through a combina- tion of hardware and ...
Page 12
AND current has dropped below the required threshold. www.national.com Figure 21 shows the typical charging profile for a Li-ion bat- tery. FIGURE 21. Li-ion Charge Profile 12 30138224 ...
Page 13
Bill of Materials Item Designator 1 U17 Flash-Based, 8-Bit CMOS Microcontroller, 2K (x14-Bit words) Program Memory, 128 Bytes Data Memory, 25 I/O pins, 28-Pin SOIC, Standard VDD Range, Extended Temperature 2 C1, C2, C3, C4, C5, C6, C7, C8, C9, ...
Page 14
Item Designator 31 R3, R4, R22, R23, R30, R36, R42, R43, R45, R72, R100, R101, R102, R105, R106, R111, R119, R120, R121, R300, R400 R7, R13 35 R8, R12, R24, R34 R11, ...
Page 15
Item Designator 71 U11, U12 Dual Micro-Power Rail-to-Rail Input CMOS Comparator with Open Drain Output 72 L1 Description Inductor 2 uH EFD-30 core 15 Manufacturer Part Number National SM72375 Semiconductor PULSE PA2965-203NL www.national.com Qty 2 1 ...
Page 16
... For more National Semiconductor product information and proven design tools, visit the following Web sites at: www.national.com Products Amplifiers www.national.com/amplifiers Audio www.national.com/audio Clock and Timing www.national.com/timing Data Converters www.national.com/adc Interface www.national.com/interface LVDS www.national.com/lvds Power Management www.national.com/power Switching Regulators www.national.com/switchers LDOs www.national.com/ldo LED Lighting www ...