SM72238,SM72240,SM72295,SM72375,SM72442,
SM72480,SM72485
Application Note 2121 SolarMagic SM3320-BATT-EV Charge Controller
Reference Design
Literature Number: SNOSB76B
SolarMagic™ SM3320-
BATT-EV Charge Controller
Reference Design
National Semiconductor
Application Note 2121
Florent Boico
February 18, 2011
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
to provide support for a wide variety of implementations, how-
ever, unless otherwise noted, this reference design system is
shown charging a 12V commercial automotive lead acid bat-
tery.
Charging Profile
Figure 1 shows the lead-acid charging profile used in this ref-
erence design:
30138201
FIGURE 1. Lead-Acid Charging Profile
If the battery voltage is very low, a slow charge current is ap-
plied and limited until the voltage rises above a pre-set thresh-
old value Vt. The full charge current is then applied. Once full
charge is detected on the voltage of the battery, the system
switches to a floating charge and maintains the battery volt-
age at a fixed threshold. At any time, the system will run in
MPPT mode if the available power is lower than the power
required to achieve voltage or current regulation.
Features
•12V Lead Acid Battery
•Vin range = 15V to 45V Vmp (50V Voc)
•Max Input Current: Isc = 11A
•MPPT algorithm for optimized photovoltaic applications
•Up to 9A charging current
•Reverse current protection
•Trickle charge and fast charge mode
•Up to 98% converter efficiency
•14.2V max charge voltage, 13.5V floating voltage
•Output voltage set-points can be re programmed
Quick Setup Procedure
Step 1: Verify lead-acid battery voltage less than 12V, higher
than 10V
Step 2: Connect battery to output terminals as shown in Fig-
ure 2
Step 3: Connect Solar panel or Solar Array Simulator to the
input terminals as shown in Figure 2.
Step 4: Verify battery charging current up to 9A (Average
slightly under 9A)
Step 5: If battery current low, verify input operates at maxi-
mum power point voltage as specified by the panel manufac-
turer
Step 6: verify charging profile follows the profile shown in
Figure 1
30138202
FIGURE 2. System Connection
SolarMagic™ is a trademark of National Semiconductor Corporation.
© 2011 National Semiconductor Corporation 301382 www.national.com
SolarMagic SM3320-BATT-EV Charge Controller Reference Design AN-2121
30138203
FIGURE 3. Charge Controller System Schematic, Part1
www.national.com 2
AN-2121
30138204
FIGURE 4. Charge Controller System Schematic, Part2
3 www.national.com
AN-2121
10V Power Supply
The following circuit shown in Figure 5 will provide a 10V
power supply rail required to properly bias the SM72295 gate
driver. The system can be configured to work with solar pan-
els up to100V (with proper components sizing) and down to
12V Vmp.
30138205
FIGURE 5. 10V Power Supply
DC/DC Converter
30138206
FIGURE 6. DC/DC Converter Stage
The DC/DC converter stage is a step up/step down four switch
converter as shown in Figure 6. This stage transfers the pow-
er from the PV panel to the load.
C18, R11, and D15 as shown in the system schematic in
Figure 3, form a snubber to reduce ripple on the switch node
on the “Buck” side of the converter. C19,R14 and D14 form a
snubber circuit to reduce ripple on the switch node of the
“Boost” side of the converter.
When the circuit operates in Buck mode, the Boost switch
node will issue small pulses at a lower frequency in order to
recharge the Bootstrap capacitor of Q2. Likewise, in Boost
mode, the Buck switch node will pulse to recharge the boot-
strap capacitor of Q1.
Specific design guidelines for the DC/DC converter can be
found in the Power Design Guidelines Application Note 2124
for power optimizers.
Specific timings related to the switches can be found in the
SM72442 and SM72295 datasheets. The waveforms in Fig-
ure 7 through Figure 10 are examples of the switching signals
of the DC/DC converter stage.
If the system is to be used at elevated power levels causing
high temperature increases in MOSFETs Q1, Q2, Q3, and/or
Q4, we recommend the use of a proper heatsink for the MOS-
FETs, especially at higher ambient temperatures. Care must
be taken to prevent electrical contact between the drains of
the MOSFETs in the process of proper heatsinking.
www.national.com 4
AN-2121
30138207
FIGURE 7. Buck Gate Drive Signals From SM72442
30138208
FIGURE 8. Switch Nodes in Buck Mode
30138209
FIGURE 9. Boost Gate Drive Signals From SM72442
30138210
FIGURE 10. Switch Nodes in Boost Mode
Programmable Modes/Gain
Settings
The voltage dividers for the output voltage sensing are set to
ensure high resolution of the output voltage while providing a
safe voltage (<5V) for the SM72442 and microcontroller.
The default resistor setting in this reference design sets a full
scale of 30V.
The programmable modes of the SM72442 used in this de-
sign are as follows:
VADC2 = 5V (50% of 4sec in BB)
VADC6 = 5V (startup at 0mA)
VADC0 = 0V. This value provides an initial output voltage limit
of 19V. However, this limit will be modified by the microcon-
troller through I2C before the controller begins supplying the
battery
VADC4 = 5V. Current limiting will be done externally so the
max current limit can be set at full scale.
Current Sense Gains and Offset
The gain of the current sensing circuit depends on the appli-
cation. In our system it was set with a gain of 0.44 V/Amps.
The gain is set by a pull-down resistor at the output of IOUT
(12) and IIN (3) pins of the SM72295 as stated in the
datasheet of the device.
5 www.national.com
AN-2121
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 circuit can be turned off to allow MPPT operation
to perform.
30138211
FIGURE 11. Start-Up Boost Circuitry
As long as the start-up circuit is activated, the duty cycle will
increase every 1ms up to its maximum value. However, the
duty cycle will still be limited by the SM72442’s internal output
voltage limiter.
The circuit is turned on when the anode of D101 and the
cathode of D100 are kept at 5V. It is disabled when that node
is set at 0V.
The circuit should be disabled 5ms after current begins to flow
into the battery to allow proper MPPT operation.
30138212
FIGURE 12. Start-up Circuit Timing Diagram
If the current drops to 0 for any reason (no light, reset, etc…)
the start-up circuit can be re-engaged according to the timing
diagram in Figure 12.
This circuit operates by sensing the average value of the gate
voltage on the main buck switch (Q1) and main boost switch
(Q4). This value is fed back to the input current sense of the
SM72442. At the same time, a constant 4.4V is set at the input
voltage sense pin of the SM72442. This results in the
SM72442 measuring a virtual power that increases each time
the duty cycle is increased and decreases each time the duty
cycle is decreased. The SM72442 will track this virtual power
and increase the duty cycle of the converter continuously.
When this circuit is de-activated, the real input voltage and
current appear at the sensing pins of the SM72442 chip which
will then perform regular MPPT operation.
Figure 13 shows the expected waveform if the panel voltage
is less than the battery voltage. The panel Vmp for this ex-
ample is 12V @ 3A and the battery voltage is at 25V. Figure
14 showcases the magnified version of the battery current
shown in Figure 13.
30138213
FIGURE 13. Start-up VPanel < VBatt
30138214
FIGURE 14. Start-up Detail of Battery Current
Note: To highlight the boosting capability of the system and
start-up circuit, the board has been re-configured to run with
a 24V battery for the experiments shown in Figure 13 and
Figure 14.
www.national.com 6
AN-2121
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 or a comparator
(U12A) connected to the output current sensing: when current
drops below the threshold value, Q2 is disabled. The thresh-
old is set to 1A by default.
Output Current Regulation
Current regulation is enforced by a comparator (U11A). The
current setting can be switched from a low current limit to a
high current limit with a bit set by the microcontroller. When
microcontroller pin RC5 (pin number 16) is set to high
impedance, the high current limit is set. When pin RC5 is set
to 0V, the low current limit is set.
In this design, the high current limit is set to 9A and the low
current limit to 0.5A.
Voltage Regulation
Voltage regulation with the SM72442 is performed internally.
The initial output voltage setting is set through pin A0 (0-5V).
The output voltage set point can then be changed through the
I2C communication interface by setting the register 0x03 bits
20:29 to the required voltage set point and bit 46 to 1.
Figure 15 shows the system performing voltage regulation on
the battery at 13.5V.
30138215
FIGURE 15. Charging Waveforms During Float
In addition to the voltage regulation, a comparator (U11B) will
reset the SM72442 and cause the DC/DC converter to shut-
down if the output voltage increases beyond the values set by
R71 and R72. When the negative input of the comparator
reaches over 5V, the SM72442 controller will be reset. The
default value corresponds to 14.6V battery voltage.
MPPT
The SM72442 chip will perform the MPPT function using an
implementation of the Perturb and Observe algorithm
method. The MPPT algorithm will extract maximum power
from the solar panel and deliver it to the battery regardless of
the panel’s characteristics. Figure 16 and Figure 17 show the
effect on the panel voltage as the MPPT algorithm maintains
constant power at the panel regardless of the voltage on the
battery.
30138216
FIGURE 16. Battery Charging with VPanel < VBattery (Boost)
30138217
FIGURE 17. Battery Charging with VPanel > VBattery (Buck)
7 www.national.com
AN-2121
Microcontroller Functions
The charge profile is implemented in the current design using
a PIC16F722 microcontroller.
NORMAL OPERATION
The following flowchart in Figure 18 details the operation of
the microcontroller needed to achieve the desired charging
pattern.
Modification to this flowchart can easily be done and pro-
grammed to include:
- Modified threshold depending on temperature (if battery
temperature information available).
- Timer to maintain high voltage threshold for a certain time
before switching to floating charge to maximize energy stored
in the battery.
- Pulse charging during the float charge period.
The microcontroller is programmed using a 10 pin CLE-105
connector (J5). The connections are:
•1: NC (Not Connected)
•2: PGD/ICSPDAT
•3: GND
•4: PGC/ICSPCLK
•5: NC
•6: GND
•7: +5Vdc
•8: MCLR!
•9: GND
•10: NC
Refer to the Microchip website for proper programming/de-
bugging of the PIC16F familly microcontrollers.
30138219
FIGURE 18. Basic Operational Flowchart
www.national.com 8
AN-2121
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 the RESET line of the SM72442 chip. If needed, the
start-up circuit is turned on by setting RB5 to ‘1’ (5V) (If the
microcontroller used in the application is running below 5V, a
level shifting circuit will be necessary).
Once current begins to flow in the battery the start-up circuit
can be released.
While the start-up circuit is enabled, the panel current and
voltage are not available through I2C. The corresponding
registers can be read but will not contain the correct values.
SAFETY FEATURE
The microcontroller is programmed by default to stop charg-
ing the battery if the output voltage is above 14.5V or below
8V.
Microcontroller Program Code
The following flowchart in Figure 19 is representative of the
code programmed inside the microcontroller:
30138225
FIGURE 19. Microcontroller Code Flowchart
The check_lead_acid function issues a value depending on
the state of the battery as detected by the voltage. The main
function uses this value to issue the proper action. The other
functions in the program are essentially I2C driver functions
and low level port setup functions.
9 www.national.com
AN-2121
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 running in high current mode, the voltage sensed
by the SM72442 is not the battery voltage. If the current lim-
itation is not necessary, such as panels with limited power
capabilities, the voltage used by the check_lead_acid() func-
tion could be changed to the value recovered from the
SM72442 through I2C instead of using the microcontroller’s
ADC.
This function verifies the state of the battery by sensing its
voltage and returns an 8 bit number related to the state of the
battery:
0: No change
1: Battery reached the full State Of Charge voltage
2: Battery voltage is low
3: Battery voltage is too low or battery damaged/
disconnected
4: Battery voltage is above the acceptable value: battery
damaged or disconnected
5: Battery voltage has reached above 13.6V. This is
usually due to the lower limit on the duty cycle of the buck
converter. When the battery stays in floating charge state
for too long, the converter will keep pumping a minimum
current into the battery which could result in an increase
of the battery voltage beyond the desired floating charge
voltage range.
6: Battery voltage has returned to an acceptable value
States 5 and 6 correspond to the state of charge of the battery
after it has reached it's floating charge state value of 13.5V.
When “5” is returned by this function, the program will com-
pletely cut the charge into the battery (by issuing a reset to
the SM72442 via PORTB of the microcontroller). When “6” is
returned by this function, the program will re-enable the float-
ing charge into the battery by releasing the reset on the
SM72442.
FUNCTION “Main()”
The “Main” function calls the” Init()” function, which simply in-
titializes the variables and the registers. The program then
enters an infinite while-loop in which the values of the sensed
voltages and current are recovered from the SM72442
through I2C. The function “check_lead_acid()” is called and
returns a value based on the voltage of the battery. The “Main”
function uses this value to modify the behavior of the system.
The following lists the values returned from the
“check_lead_acid()” function the corresponding action the
“Main” function will take:
1 (fully charged battery): The floating charge voltage
setpoint will be sent to SM72442 through I2C
2 (heavily discharged battery): Trickle charge will be
applied
3 (battery voltage too low): System shuts down by keeping
the SM72442 in reset mode (bit RB2 set)
4 (battery voltage too high): System shuts down by
keeping the SM72442 in reset mode (bit RB2 set)
5 (battery voltage slightly high in floating charge): System
shuts down by keeping the SM72442 in reset mode (bit
RB2 set) and hysteresis flag set
6 (battery voltage dropped below 13V after hysteresis flag
set): Re-enable SM72442, hysteresis flag reset
The Main function also resets the watchdog timer once every
iteration of the while-loop.
FUNCTION “get_i2c_data”
This function reads the sampled voltage of pin AIIN(19), AVIN
(15), AIOUT(21) and AVOUT(17) of the SM72442. The data
is fetched through the I2C channel. The function updates the
global variable “outval” which is an array of unsigned 16 bit
integers. The data only occupies 10bits of each integer (full
scale=1023).
outval[0] = input current
outval[1] = input voltage
outval[2] = output current
outval[3] = output voltage
FUNCTION “send_i2c_command(char number)”
Sends an I2C communication string. Each byte sent is stored
in the global array “i2c_buffer”. The argument “number” indi-
cates how many bytes from the buffer will be sent (starting
with i2c_buffer[0]). Refer to the datasheet and I2C and
SM_bus standards documentation for complete protocol in-
formation. The main use of this function is to change the
voltage limit settings in the SM72442.
FUNCTION “Set_Voutmax()”
This will read the “voutmax” variable set in the main and sends
the proper I2C command to the SM72442 to regulate that
voltage.
FUNCTION “Check_low_current()”
This function is called by the “Main” function and controls the
start-up circuitry to force the duty cycle of the converter up if
the current becomes close to 0.
The following Figure 20 summarizes the overall structure of
the program: (arrows from the main represent calls to the
functions)
www.national.com 10
AN-2121
30138226
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 software changes. In order to re-
configure the board for Li-ion charging, the following steps
need to be done:
1. The voltage sensing resistors R103, R104, R51, R52 and
R53 and OVP resistors R71 and R72 need to be changed
to the proper values. It is critical for this application that
the full scale voltage range for sensing is as close as
possible to the voltage of the battery to maximize the
resolution of the sensed voltage. The level of the OVP
circuit needs to be scaled so that it does not trigger when
the battery approaches full SOC but at a voltage slightly
higher.
R103 and R104 set the voltage at the input of the
microcontroller. The voltage at the input of the
microcontroller is:
R103 and R104 should be chosen so that the maximum
expected battery voltage creates a voltage close to 5V to
maximize resolution (but less than 5V to avoid saturating
the measure).
R51, R52 and R53 are for the voltage measurement of
the SM72442 and should be modified in the same way:
R21 needs to be set to zero ohm (short).
Once the values are picked, the proper threshold needs
to be programmed through I2C. The maximum level
(0x3FF) is now VAVOUT = 5V at the input of the SM72442.
Finally, the overvoltage protection should be adjusted to:
The OVP level is set at VHARD_OVP = 5v.
2. The proper voltage setpoints and charging curve need to
be programmed in the microcontroller. The initial voltage
limit is set by R28 and R38. Voltage limit setpoint is
AVOUT = A0. Once overridden through I2C, the voltage
at A0 is not used anymore. Hence, there is the option of
setting the value through resistors R28 and R38 or by
programming it from the microcontroller into SM72442
through I2C each time the SM72442 is reset/powered.
3. Proper current limits also need to be set if required by the
battery model. The current limit value is set when the
voltage at pin 3 of U11A equals the voltage at at pin 2.
Hence, R111 and R112 will need to be adjusted
accordingly.
4. The software needs to be changed to follow the Li-ion
charge control profile: battery voltage is set either by
hardware as stated above, which requires no action from
the software, or it is set from the microcontroller through
the I2C interface similar to the Lead Acid battery.
5. Finally, the software needs to include the full State-Of-
Charge charge cut-off: When the battery reaches its full
voltage and current has dropped below 500mA (can vary
depending on battery), charge is cut-off and the battery
is considered fully charged (no trickle charge of Li-ion
batteries should be done). It is important to remember
that current can drop below 500mA during the charge
when solar power becomes unavailable (low light
intensity). Therefore the charge cut-off needs to be
programmed to occur only when the battery voltage is at
11 www.national.com
AN-2121
Bill of Materials
Item Designator Description Manufacturer Part Number Qty
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
Microchip Technology PIC16F722-E/SS or
PIC16F722-I/SS
1
2C1, C2, C3, C4, C5, C6,
C7, C8, C9, C10, C11,
C12, C13, C14, C16,
C20, C25, C27, C28,
C30, C36, C42, C44,
C45, C47, C48, C53,
C55, C57, C67, C70,
C72
Ceramic, X7R, 50V, 10% MuRata C3225X7R1H225k/2.50 32
3 C15, C17, C22, C26,
C32, C49, C50, C51,
C52, C65
Ceramic, X7R, 25V, 10% MuRata GRM188R71E104KA01
D
10
4 C18, C19 Ceramic, C0G/NP0, 100V, 5% AVX 08051A471JAT2A 2
5 C21 Ceramic, X7R, 100V, 10% Taiyo Yuden HMK212B7104KG-T 1
6 C23, C33, C34, C38 Ceramic, X7R, 16V, 10% Taiyo Yuden EMK212B7225KG-T 4
7 C24 Ceramic, X7R, 50V, 10% MuRata GRM188R71H331KA01
D
1
8 C29, C37, C39, C59 Ceramic, X7R, 100V, 20% AVX 06031C103MAT2A 4
9 C31, C35, C40 Ceramic, X7R, 16V, 10% Taiyo Yuden EMK212B7105KG-T 3
10 C46, C54 Ceramic, X7R, 16V, 10% AVX 0805YC474KAT2A 2
11 C58, C60, C61, C62,
C66, C69
Ceramic, C0G/NP0, 100V, 5% TDK C1608C0G2A102J 6
12 C73 Ceramic, C0G/NP0, 50V, 5% TDK C1608C0G1H151J 1
13 C88 CAP, CERM, 0.1uF, 25V, +/-5%, X7R, 0603 AVX 06033C104JAT2A 1
14 C100, C102 CAP, CERM, 1000pF, 100V, +/-10%, X8R,
0603
TDK C1608X8R2A102K 2
15 C101 CAP, CERM, 0.1uF, 16V, +/-5%, X7R, 0603 AVX 0603YC104JAT2A 1
16 D2, D7, D9, D12, D13,
D14, D15
Vr = 100V, Io = 1A, Vf = 0.77V Diodes Inc. DFLS1100-7 7
17 D3, D4, D5, D6 Vr = 30V, Io = 1A, Vf = 0.47V ON Semiconductor MBR130T1G 4
18 D100, D101 Vr = 30V, Io = 0.2A, Vf = 0.65V Diodes Inc. BAT54-7-F 2
20 J1, J2, J3, J4 PC Quick-Fit 0.250 Tab Keystone 4908 4
21 J5 CONN RCPT 10POS .8MM DL GOLD SMD SAMTEC CLE-105-01-G-DV 1
22 J11, J12, J13, J14 200 mill pad with 165 mill hole NONE NONE 4
23 L4 Shielded Drum Core, 0.56A, 0.907 Ohm Coiltronics DR74-221-R 1
24 P1 Header, TH, 100mil, 1x2, Tin plated, 230 mil
above insulator
Samtec Inc. TSW-102-07-T-S 1
25 Q1, Q2, Q3, Q4 40A, 53nC, rDS(on) @ 4.5V = 0.018 Ohm International Rectifier IRF3205ZPBF 4
26 Q7, Q8, Q9 0.26A, 0.81nC, rDS(on) @ 4.5V = 3 ON Semiconductor 2N7002ET1G 3
27 Q11 Transistor, NPN, 40V, 0.15A, SOT-23 Diodes Inc. MMBT4401-7-F 1
28 Q200 MOSFET, P-CH, -50V, -130A, SOT-323 Diodes Inc. BSS84W-7-F 1
29 R1, R10 1%, 2W Stackpole CSNL 2 0.004 1% R 2
30 R2, R54 1%, 0.125W Vishay-Dale CRCW0805178kFKEA 2
13 www.national.com
AN-2121
Item Designator Description Manufacturer Part Number Qty
31 R3, R4, R22, R23, R30,
R36, R42, R43, R45,
R72, R100, R101,
R102, R105, R106,
R111, R119, R120,
R121, R300, R400
1%, 0.1W Vishay-Dale CRCW060310k0FKEA 21
32 R5 1%, 0.1W Vishay-Dale CRCW0603124kFKEA 1
33 R6 1%, 0.125W Vishay-Dale CRCW08051R00FNEA 1
34 R7, R13 1%, 0.25W Vishay-Dale CRCW120619k6FKEA 2
35 R8, R12, R24, R34 1%, 0.1W Vishay-Dale CRCW0603499RFKEA 4
36 R9 1%, 0.1W Vishay-Dale CRCW060312k4FKEA 1
37 R11, R14 1%, 1W Vishay-Dale CRCW121810R0FKEK 2
38 R15 1%, 0.1W Vishay-Dale CRCW06034k22FKEA 1
39 R17 1%, 0.1W Panasonic ERJ-3RQFR33V 1
40 R18, R19 RES, 10 ohm, 5%, 0.125W, 0805 Vishay-Dale CRCW080510R0JNEA 2
41 R20, R29, R31, R47,
R48
1%, 0.1W, RES, 2.00k ohm, 1%, 0.1W, 0603 Vishay-Dale CRCW06032k00FKEA 5
42 R21 1%, 0.1W Vishay-Dale CRCW060349R9FKEA 1
43 R25, R35, R37, R44 5%, 0.1W Vishay-Dale CRCW06030000Z0EA 4
44 R26, R56, R87, R116 1%, 0.1W Vishay-Dale CRCW060360k4FKEA 4
45 R71, R73 1%, 0.1W, RES, 19.1k ohm, 1%, 0.1W, 0603 Vishay-Dale CRCW060319k1FKEA 3
46 R32, R33 RES, 4.99 ohm, 1%, 0.125W, 0805 Vishay-Dale CRCW08054R99FNEA 2
47 R38 1%, 0.1W Vishay-Dale CRCW060331k6FKEA 1
48 R39 RES, 1.00Meg ohm, 1%, 0.1W, 0603 Vishay-Dale CRCW06031M00FKEA 1
49 R40 1%, 0.1W Vishay-Dale CRCW0603150kFKEA 1
50 R41 RES, 45.3k ohm, 1%, 0.1W, 0603 Vishay-Dale CRCW060345K3FKEA 1
51 R51, R52 RES, 12.4k ohm, 1%, 0.25W, 1206 Vishay-Dale CRCW120612K4FKEA 2
52 R53, R103 RES, 4.02k ohm, 1%, 0.1W, 0603 Vishay-Dale CRCW06034K02FKEA 2
54 R104 RES, 24.9k ohm, 1%, 0.1W, 0603 Vishay-Dale CRCW060324K9FKEA 1
55 R107, R108 RES, 270k ohm, 1%, 0.1W, 0603 Yageo America RC0603FR-07270KL 2
56 R109 RES, 340k ohm, 1%, 0.1W, 0603 Yageo America RC0603FR-07340KL 1
57 R110, R122 RES, 100k ohm, 1%, 0.1W, 0603 Yageo America RC0603FR-07100KL 2
58 R112 RES, 511k ohm, 1%, 0.1W, 0603 Vishay-Dale CRCW0603511KFKEA 1
59 R113, R117 RES, 22k ohm, 5%, 0.1W, 0603 Vishay-Dale CRCW060322K0JNEA 2
61 R118 RES, 105k ohm, 1%, 0.1W, 0603 Vishay-Dale CRCW0603105KFKEA 1
62 R200 RES, 604 ohm, 1%, 0.1W, 0603 Vishay-Dale CRCW0603604RFKEA 1
63 R500, R600 RES, 100k ohm, 1%, 0.1W, 0603 Vishay-Dale CRCW0603100KFKEA 2
64 TP1, TP2 Test Point, SMT, Miniature Keystone Electronics 5015 2
65 U1 150 mA, 100V Step-Down Switching Regulator National
Semiconductor
SM72485 1
66 U2, U3 1.6V, LLP-6 Factory Preset Temperature
Switch and Temperature Sensor
National
Semiconductor
SM72480 2
67 U5 Series of Adjustable Micropower Voltage
Regulators
National
Semiconductor
SM72238 1
68 U7 Driver National
Semiconductor
SM72295 1
69 U8 Digital Controller National
Semiconductor
SM72442 1
70 U9 5-Pin Microprocessor Reset Circuits National
Semiconductor
SM72240 1
www.national.com 14
AN-2121
Item Designator Description Manufacturer Part Number Qty
71 U11, U12 Dual Micro-Power Rail-to-Rail Input CMOS
Comparator with Open Drain Output
National
Semiconductor
SM72375 2
72 L1 Inductor 2 uH EFD-30 core PULSE PA2965-203NL 1
15 www.national.com
AN-2121
AN-2121 SolarMagic SM3320-BATT-EV Charge Controller Reference Design
For more National Semiconductor product information and proven design tools, visit the following Web sites at:
www.national.com
Products Design Support
Amplifiers www.national.com/amplifiers WEBENCH® Tools www.national.com/webench
Audio www.national.com/audio App Notes www.national.com/appnotes
Clock and Timing www.national.com/timing Reference Designs www.national.com/refdesigns
Data Converters www.national.com/adc Samples www.national.com/samples
Interface www.national.com/interface Eval Boards www.national.com/evalboards
LVDS www.national.com/lvds Packaging www.national.com/packaging
Power Management www.national.com/power Green Compliance www.national.com/quality/green
Switching Regulators www.national.com/switchers Distributors www.national.com/contacts
LDOs www.national.com/ldo Quality and Reliability www.national.com/quality
LED Lighting www.national.com/led Feedback/Support www.national.com/feedback
Voltage References www.national.com/vref Design Made Easy www.national.com/easy
PowerWise® Solutions www.national.com/powerwise Applications & Markets www.national.com/solutions
Serial Digital Interface (SDI) www.national.com/sdi Mil/Aero www.national.com/milaero
Temperature Sensors www.national.com/tempsensors SolarMagic™ www.national.com/solarmagic
PLL/VCO www.national.com/wireless PowerWise® Design
University
www.national.com/training
THE CONTENTS OF THIS DOCUMENT ARE PROVIDED IN CONNECTION WITH NATIONAL SEMICONDUCTOR CORPORATION
(“NATIONAL”) PRODUCTS. NATIONAL MAKES NO REPRESENTATIONS OR WARRANTIES WITH RESPECT TO THE ACCURACY
OR COMPLETENESS OF THE CONTENTS OF THIS PUBLICATION AND RESERVES THE RIGHT TO MAKE CHANGES TO
SPECIFICATIONS AND PRODUCT DESCRIPTIONS AT ANY TIME WITHOUT NOTICE. NO LICENSE, WHETHER EXPRESS,
IMPLIED, ARISING BY ESTOPPEL OR OTHERWISE, TO ANY INTELLECTUAL PROPERTY RIGHTS IS GRANTED BY THIS
DOCUMENT.
TESTING AND OTHER QUALITY CONTROLS ARE USED TO THE EXTENT NATIONAL DEEMS NECESSARY TO SUPPORT
NATIONAL’S PRODUCT WARRANTY. EXCEPT WHERE MANDATED BY GOVERNMENT REQUIREMENTS, TESTING OF ALL
PARAMETERS OF EACH PRODUCT IS NOT NECESSARILY PERFORMED. NATIONAL ASSUMES NO LIABILITY FOR
APPLICATIONS ASSISTANCE OR BUYER PRODUCT DESIGN. BUYERS ARE RESPONSIBLE FOR THEIR PRODUCTS AND
APPLICATIONS USING NATIONAL COMPONENTS. PRIOR TO USING OR DISTRIBUTING ANY PRODUCTS THAT INCLUDE
NATIONAL COMPONENTS, BUYERS SHOULD PROVIDE ADEQUATE DESIGN, TESTING AND OPERATING SAFEGUARDS.
EXCEPT AS PROVIDED IN NATIONAL’S TERMS AND CONDITIONS OF SALE FOR SUCH PRODUCTS, NATIONAL ASSUMES NO
LIABILITY WHATSOEVER, AND NATIONAL DISCLAIMS ANY EXPRESS OR IMPLIED WARRANTY RELATING TO THE SALE
AND/OR USE OF NATIONAL PRODUCTS INCLUDING LIABILITY OR WARRANTIES RELATING TO FITNESS FOR A PARTICULAR
PURPOSE, MERCHANTABILITY, OR INFRINGEMENT OF ANY PATENT, COPYRIGHT OR OTHER INTELLECTUAL PROPERTY
RIGHT.
LIFE SUPPORT POLICY
NATIONAL’S PRODUCTS ARE NOT AUTHORIZED FOR USE AS CRITICAL COMPONENTS IN LIFE SUPPORT DEVICES OR
SYSTEMS WITHOUT THE EXPRESS PRIOR WRITTEN APPROVAL OF THE CHIEF EXECUTIVE OFFICER AND GENERAL
COUNSEL OF NATIONAL SEMICONDUCTOR CORPORATION. As used herein:
Life support devices or systems are devices which (a) are intended for surgical implant into the body, or (b) support or sustain life and
whose failure to perform when properly used in accordance with instructions for use provided in the labeling can be reasonably expected
to result in a significant injury to the user. A critical component is any component in a life support device or system whose failure to perform
can be reasonably expected to cause the failure of the life support device or system or to affect its safety or effectiveness.
National Semiconductor and the National Semiconductor logo are registered trademarks of National Semiconductor Corporation. All other
brand or product names may be trademarks or registered trademarks of their respective holders.
Copyright© 2010 National Semiconductor Corporation
For the most current product information visit us at www.national.com
National Semiconductor
Americas Technical
Support Center
Email: support@nsc.com
Tel: 1-800-272-9959
National Semiconductor Europe
Technical Support Center
Email: europe.support@nsc.com
National Semiconductor Asia
Pacific Technical Support Center
Email: ap.support@nsc.com
National Semiconductor Japan
Technical Support Center
Email: jpn.feedback@nsc.com
www.national.com
IMPORTANT NOTICE
Texas Instruments Incorporated and its subsidiaries (TI) reserve the right to make corrections, modifications, enhancements, improvements,
and other changes to its products and services at any time and to discontinue any product or service without notice. Customers should
obtain the latest relevant information before placing orders and should verify that such information is current and complete. All products are
sold subject to TI’s terms and conditions of sale supplied at the time of order acknowledgment.
TI warrants performance of its hardware products to the specifications applicable at the time of sale in accordance with TI’s standard
warranty. Testing and other quality control techniques are used to the extent TI deems necessary to support this warranty. Except where
mandated by government requirements, testing of all parameters of each product is not necessarily performed.
TI assumes no liability for applications assistance or customer product design. Customers are responsible for their products and
applications using TI components. To minimize the risks associated with customer products and applications, customers should provide
adequate design and operating safeguards.
TI does not warrant or represent that any license, either express or implied, is granted under any TI patent right, copyright, mask work right,
or other TI intellectual property right relating to any combination, machine, or process in which TI products or services are used. Information
published by TI regarding third-party products or services does not constitute a license from TI to use such products or services or a
warranty or endorsement thereof. Use of such information may require a license from a third party under the patents or other intellectual
property of the third party, or a license from TI under the patents or other intellectual property of TI.
Reproduction of TI information in TI data books or data sheets is permissible only if reproduction is without alteration and is accompanied
by all associated warranties, conditions, limitations, and notices. Reproduction of this information with alteration is an unfair and deceptive
business practice. TI is not responsible or liable for such altered documentation. Information of third parties may be subject to additional
restrictions.
Resale of TI products or services with statements different from or beyond the parameters stated by TI for that product or service voids all
express and any implied warranties for the associated TI product or service and is an unfair and deceptive business practice. TI is not
responsible or liable for any such statements.
TI products are not authorized for use in safety-critical applications (such as life support) where a failure of the TI product would reasonably
be expected to cause severe personal injury or death, unless officers of the parties have executed an agreement specifically governing
such use. Buyers represent that they have all necessary expertise in the safety and regulatory ramifications of their applications, and
acknowledge and agree that they are solely responsible for all legal, regulatory and safety-related requirements concerning their products
and any use of TI products in such safety-critical applications, notwithstanding any applications-related information or support that may be
provided by TI. Further, Buyers must fully indemnify TI and its representatives against any damages arising out of the use of TI products in
such safety-critical applications.
TI products are neither designed nor intended for use in military/aerospace applications or environments unless the TI products are
specifically designated by TI as military-grade or "enhanced plastic."Only products designated by TI as military-grade meet military
specifications. Buyers acknowledge and agree that any such use of TI products which TI has not designated as military-grade is solely at
the Buyer's risk, and that they are solely responsible for compliance with all legal and regulatory requirements in connection with such use.
TI products are neither designed nor intended for use in automotive applications or environments unless the specific TI products are
designated by TI as compliant with ISO/TS 16949 requirements. Buyers acknowledge and agree that, if they use any non-designated
products in automotive applications, TI will not be responsible for any failure to meet such requirements.
Following are URLs where you can obtain information on other Texas Instruments products and application solutions:
Products Applications
Audio www.ti.com/audio Communications and Telecom www.ti.com/communications
Amplifiers amplifier.ti.com Computers and Peripherals www.ti.com/computers
Data Converters dataconverter.ti.com Consumer Electronics www.ti.com/consumer-apps
DLP®Products www.dlp.com Energy and Lighting www.ti.com/energy
DSP dsp.ti.com Industrial www.ti.com/industrial
Clocks and Timers www.ti.com/clocks Medical www.ti.com/medical
Interface interface.ti.com Security www.ti.com/security
Logic logic.ti.com Space, Avionics and Defense www.ti.com/space-avionics-defense
Power Mgmt power.ti.com Transportation and Automotive www.ti.com/automotive
Microcontrollers microcontroller.ti.com Video and Imaging www.ti.com/video
RFID www.ti-rfid.com
OMAP Mobile Processors www.ti.com/omap
Wireless Connectivity www.ti.com/wirelessconnectivity
TI E2E Community Home Page e2e.ti.com
Mailing Address: Texas Instruments, Post Office Box 655303, Dallas, Texas 75265
Copyright ©2011, Texas Instruments Incorporated
