LM3559 [TI]
LM3559 Synchronous Boost Flash Driver with Dual 900 mA High Side Current Sources (1.8A Total Flash Current); 与双900毫安高压侧电流源（ 1.8A总闪光灯电流） LM3559同步升压型闪光灯驱动器
| 型号： | LM3559 |
| 厂家： | 
TEXAS INSTRUMENTS |
| 描述： | LM3559 Synchronous Boost Flash Driver with Dual 900 mA High Side Current Sources (1.8A Total Flash Current) |
| 文件： | 总42页 (文件大小：3048K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
LM3559
LM3559 Synchronous Boost Flash Driver with Dual 900 mA High Side Current
Sources (1.8A Total Flash Current)
Literature Number: SNVS624
June 9, 2011
LM3559
Synchronous Boost Flash Driver with Dual 900 mA High
Side Current Sources (1.8A Total Flash Current)
General Description
Features
The LM3559 is a 2MHz fixed-frequency synchronous boost
converter with two 900 mA constant current drivers for high-
current white LEDs. The dual high-side current sources allow
for grounded cathode LED operation and can be tied together
for providing flash currents of up to 1.8A. An adaptive regu-
lation method ensures the current for each LED remains in
regulation and maximizes efficiency.
Dual High-Side Current Sources Allow for Grounded
■
Cathode LED Operation
Accurate and Programmable LED Current from 28.125mA
to 1.8A
■
Optimized Flash Current During Low Battery Conditions
■
■
■
■
Independent LED Current Source Programmability
>90% Efficiency
Ultra-Small (Total) Solution Size: < 26mm2
The LM3559 is controlled via an I2C-compatible interface.
Features include: an internal 4-bit ADC to monitor the LED
voltage, independent LED current control, a hardware flash
enable allowing a logic input to trigger the flash pulse, dual
TX inputs which force the flash pulse into a low-current torch
mode allowing for synchronization to RF power amplifier
events or other high-current conditions, an integrated com-
parator designed to monitor an NTC thermistor and provide
an interrupt to the LED current, an input voltage monitor to
monitor low battery conditions, and a flash current scale-back
feature that actively monitors the battery voltage and opti-
mizes the flash current during low battery voltage conditions.
Additionally, an active high HWEN input provides a hardware
shutdown during system software failures.
Four Operating Modes: Torch, Flash, Privacy Indicate,
and Message Indicator
■
4-bit ADC for VLED Monitoring
■
■
■
■
Battery Voltage Sensing and Current Scale-Back
LED Thermal Sensing and Current Scale-Back
Hardware Flash and Torch Enable
Dual Synchronization Inputs for RF Power Amplifier Pulse
Events
■
LED and Output Disconnect During Shutdown
■
■
■
■
Open and Short LED Detection
400 kHz I2C-Compatible Interface
The 2MHz switching frequency, over-voltage protection and
adjustable current limit allow for the use of tiny, low profile (1
µH or 2.2 µH) inductors and (10 µF) ceramic capacitors. The
device is available in a ultra-small 16-bump (1.97mm x
1.97mm x 0.6mm) micro SMD package and operates over the
-40°C to +85°C temperature range.
Active Low Hardware Reset
16-Bump (1.97mm x 1.97mm x 0.6mm) micro SMD
■
Applications
Camera Phone LED Flash
■
■
White LED Biasing
Typical Application Circuit
30102801
© 2011 National Semiconductor Corporation
301028
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Application Circuit Component List
Component
L
Manufacturer
Toko
Value
1µH
Part Number
FDSD0312-1R0
GRM188R60J106M
PWF-4
Size (mm)
3 x 3 x 1.2
Rating
3.3A
CIN/COUT
LEDs
Murata
10 µF
1.6 × 0.8 × 0.8 (0603)
6.3V
Lumiled
VF = 3.6@ 1A
Connection Diagram
30102802
16-Bump 1.97 mm x 1.97 mm x 0.6 mm micro SMD Package TLA16
XY (Date Code), TT (Die Traceability)
Ordering Information
Order Number
LM3559TLE
LM3559TLX
Package
micro SMD
micro SMD
Supplied As
No-Lead
250 units, Tape-and-Reel
3000 units, Tape-and-Reel
YES (NOPB)
YES (NOPB)
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2
Pin Descriptions
Pin
A1
Name
LED1
OUT
Function
High Side Current Source Output for Flash LED1.
A2, B2
A3, B3
A4, B4
B1
Step-Up DC/DC Converter Output. Connect a 10 µF ceramic capacitor between this pin and GND.
Drain Connection for Internal NMOS and Synchronous PMOS Switches.
Ground
SW
GND
LED2
LEDI/NTC
High-Side Current Source Output for Flash LED2.
Configureable as a High-Side Current Source Output for Indicator LED or Comparator Input for
LED Temperature Sensing.
C1
Configureable as a Dual-Polarity RF Power Amplifier Synchronization Input, a hardware Torch
mode enable, or as a General Purpose Logic I/O. This pin has an internal 300 kΩ pulldown to
GND.
TX1/TORCH/
GPIO1
C2
C3
C4
D1
STROBE
IN
Active High Hardware Flash Enable. Drive STROBE high to turn on the Flash current pulse. This
pin has an internal 300 kΩ pulldown to GND.
Input Voltage Connection. Connect IN to the input supply, and bypass to GND with a minimum 10
µF or larger ceramic capacitor.
TX2/INT/GPIO2 Configurable as a Dual-Polarity Power Amplifier Synchronization Input, an Interrupt Output, or as
a General Purpose Logic I/O. This pin has an internal 300 kΩ pulldown to GND.
D2
D3
SDA
SCL
Serial Data Input/Output. High impedance in shutdown or in power down.
Serial Clock Input. High impedance in shutdown or in power down.
Logic High Hardware Enable. HWEN is a high impedance input and is normally connected with
an external pull up resistor to a logic high voltage.
D4
HWEN
3
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Absolute Maximum Ratings (Note 1, Note
2)
Operating Ratings (Note 1, Note 2)
VIN
2.5V to 5.5V
-40°C to +125°C
-40°C to +85°C
Junction Temperature (TJ)
If Military/Aerospace specified devices are required,
please contact the National Semiconductor Sales Office/
Distributors for availability and specifications.
Ambient Temperature (TA)
(Note 5)
VIN
-0.3V to 6V
Thermal Properties
VSCL, VSDA, VHWEN, VSTROBE, VTX1
VTX2, VLED1, VLED2, VLEDI/NTC
,
-0.3V to the
lesser of (VIN
+0.3V) w/ 6.0V
max
Thermal Junction-to-Ambient
Resistance (θJA
(Note 6)
)
50.4°C/W
VSW, VOUT
-0.3V to +6V
ESD Caution Note:
Continuous Power Dissipation
National Semiconductor recommends that all integrated cir-
cuits be handled with appropriate ESD precautions. Failure to
observe proper ESD handling techniques can result in dam-
age to the device.
(Note 3)
Junction Temperature (TJ-MAX
Internally Limited
+150°C
)
Storage Temperature Range
Maximum Lead Temperature
(Soldering)
-65°C to +150°C
(Note 4)
ESD Rating
2kV
(Human Body Model)
Electrical Characteristics (Note 2, Note 7)
Limits in standard typeface are for TA = +25°C. Limits in boldface type apply over the full operating ambient temperature range
(-40°C ≤ TA ≤ +85ºC). Unless otherwise specified, VIN = 3.6V, VHWEN = VIN.
Symbol
Parameter
Conditions
Min
-7%
-4%
Typ
Max
+7%
+4%
Units
Current Source Specifications
900 mA
Flash
Current
Setting, per
current
source
-40°C ≤ TA
≤ +85°C
1800
TA = +25°C
ILED1+ILED2,
Current Source
Accuracy
ILED
mA
3.0V ≤VIN ≤4.2V,
VOUT = 4.5V
28.125 mA
Torch
Current ,
per current
source
-40°C ≤ TA
≤ +85°C
-10%
4.925
56.2
270
+10%
5.075
Current Source
Regulation
Voltage
ILED = 1.8A (ILED1 + ILED2
)
VOUT - VLED1/2
mV
V
VOUT = 4.5V
Output Over-
Voltage Protection
Trip Point(Note 9)
ON Threshold
OFF Threshold
5
VOVP
4.88
Step-Up DC/DC Converter Specifications
PMOS Switch On-
Resistance
RPMOS
RNMOS
IPMOS = 1A
80
80
mΩ
mΩ
NMOS Switch On-
Resistance
INMOS = 1A
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Symbol
Parameter
Conditions
Min
1.2
Typ
Max
1.6
Units
Flash
Duration
Register
Bits [6:5] =
00
1.4
Flash
Duration
Register
Bits [6:5] =
01
1.8
2.4
2.9
2.1
2.7
3.2
2.3
3
Switch Current
Limit (Note 8)
ICL
A
3.0V ≤ VIN ≤ 4.2V
Flash
Duration
Register
Bits [6:5] =
10
Flash
Duration
Register
Bits [6:5] =
11
3.5
Output Short-
Circuit Current
Limit
IOUT_SC
VOUT < 2.3V
350
18
mA
mA
Register 0x12, bits[2:0] = 111, 2.7V ≤
VIN ≤ 4.2V, VLEDI/NTC = 2V
ILEDI/NTC
Indicator Current
16
20
Configuration Register 1, bit [4] = 1,
Comparator Trip
Threshold
VTRIP
fSW
0.97
1.8
1
2
1.03
2.2
V
3.0V ≤ VIN ≤ 4.2V
Switching
Frequency
MHz
2.7V ≤ VIN ≤ 5.5V
Device Not Switching, VOUT = 3V
Device Switching, VOUT = 4.5V
650
µA
Quiescent Supply
Current
1.55
mA
IQ
Indicate Mode, Indicator Register Bits
[2:0] = 111,VLEDI/NTC = 2V
590
750
1
µA
µA
Shutdown Supply
Current
HWEN =
GND
ISHDN
2.7V ≤ VIN ≤ 5.5V
HWEN =
VIN, Enable
Standby Supply
Current
ISTBY
1.25
2.4
µA
2.7V ≤ VIN ≤ 5.5V
Register
Bits [1:0] =
00
VIN Monitor
Threshold
VIN_TH
VIN Monitor Register = 0x01
VIN Monitor Register = 0x08
TX_ Low to High,
2.85
2.85
2.9
2.9
2.95
2.95
V
V
VIN Flash Monitor
Threshold
VIN_FLASH_TH
Flash-to-Torch
LED Current
Settling Time
tTX
20
16
µs
ILED1 + ILED2 = 1.8A to 112.5mA
Time from when
ILED hits target until
VLED data is
available
ADC Delay Register Bit [5] = 1
tD
µs
V
ADC Delay Register Bit [5] = 0
ADC Delay Register Bits [4:0] = 0000
250
4.6
VF_ADC
ADC Threshold
VLED Monitor Register Bits [3:0] = 1111
4.4
4.8
5
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Symbol
Parameter
Conditions
Min
Typ
Max
Units
HWEN, STROBE, TX1/TORCH/GPIO1, TX2/INT/GPIO2 Voltage Specifications
VIL
VIH
Input Logic Low
Input Logic High
0
0.4
VIN
V
V
2.7V ≤ VIN ≤ 5.5V
2.7V ≤ VIN ≤ 5.5V
1.2
Internal Pulldown
Resistance on
TX1, TX2,
RPD
300
kΩ
STROBE
I2C-Compatible Voltage Specifications (SCL, SDA)
VIL
VIH
Input Logic Low
Input Logic High
0
0.4
VIN
V
V
2.7V ≤ VIN ≤ 5.5V
1.3
2.7V ≤ VIN ≤ 5.5V
ILOAD = 3mA,
Output Logic Low
(SDA)
VOL
0.4
V
2.7V ≤ VIN ≤ 5.5V
I2C-Compatible Timing Specifications (SCL, SDA) (Note 10)
SCL(Clock
Frequency)
1/t1
400
kHz
ns
Data In Setup
Time to SCL High
t2
100
0
Data Out Stable
After SCL Low
t3
ns
SDA Low Setup
t4
Time to SCL Low
(Start)
100
100
ns
ns
SDA High Hold
Time After SCL
High (Stop)
t5
Note 1: Absolute Maximum Ratings indicate limits beyond which damage to the device may occur. Operating Ratings are conditions under which operation of
the device is guaranteed. Operating Ratings do not imply guaranteed performance limits. For guaranteed performance limits and associated test conditions, see
the Electrical Characteristics table.
Note 2: All voltages are with respect to the potential at the GND pin.
Note 3: Internal thermal shutdown circuitry protects the device from permanent damage. Thermal shutdown engages at TJ=+150°C (typ.) and disengages at
TJ=+135°C (typ.). Thermal shutdown is guaranteed by design.
Note 4: For detailed soldering specifications and information, please refer to National Semiconductor Application Note 1112: Micro SMD Wafer Level chip Scale
Package (AN-1112)
Note 5: In applications where high power dissipation and/or poor package thermal resistance is present, the maximum ambient temperature may have to be
derated. Maximum ambient temperature (TA-MAX) is dependent on the maximum operating junction temperature (TJ-MAX-OP = +125ºC), the maximum power
dissipation of the device in the application (PD-MAX), and the junction-to-ambient thermal resistance of the part/package in the application (θJA), as given by the
following equation: TA-MAX = TJ-MAX-OP – (θJA × PD-MAX).
Note 6: Junction-to-ambient thermal resistance (θJA) is taken from a thermal modeling result, performed under the conditions and guidelines set forth in the
JEDEC standard JESD51-7. The test board is a 4-layer FR-4 board measuring 102 mm x 76 mm x 1.6 mm with a 2x1 array of thermal vias. The ground plane
on the board is 50 mm x 50 mm. Thickness of copper layers are 36 µm/18 µm/18 µm/36 µm (1.5 oz/1oz/1oz/1.5 oz). Ambient temperature in simulation is 22°C,
still air. Power dissipation is 1W.
Note 7: Min and Max limits are guaranteed by design, test, or statistical analysis. Typical (Typ) numbers are not guaranteed, but do represent the most likely
norm. Unless otherwise specified, conditions for typical specifications are: VIN = 3.6V and TA = +25ºC.
Note 8: The typical curve for Current Limit is measured in closed loop using the typical application circuit, and increasing IOUT until the peak inductor current stops
increasing. The value given in the Electrical Table is measured open loop and is found by forcing current into SW until the current limit comparator threshold is
reached. Closed loop data appears higher due to the delay between the comparator trip point and the NFET turning off. This delay allows the closed loop inductor
current to ramp higher after the trip point by approximately 20 ns × VIN/L
Note 9: The typical curve for Over-Voltage Protection (OVP) is measured in closed loop using the typical application circuit . The OVP value is found by forcing
an open circuit in the LED1 and LED2 path and recording the peak value of VOUT. The value given in the Electrical Table is found in an open loop configuration
by ramping the voltage at OUT until the OVP comparator trips. The closed loop data can appear higher due to the stored energy in the inductor being dumped
into the output capacitor after the OVP comparator trips. At worst case is an open circuit condition where the output voltage can continue to rise after the OVP
comparator trips by approximately IIN×sqrt(L/COUT
)
Note 10: Guaranteed by design, not production tested.
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Typical Performance Characteristics VIN = 3.6V, COUT = 10µF, CIN = 10µF, L = 1µH (TOKO
FDSD0312-1R0, RL = 43 mΩ), Typical Application Circuit, unless otherwise noted.
LED Efficiency vs VIN
Dual LED's (Flash Brightness Codes 0xBB - 0xFF)
LED Efficiency vs VIN
Dual LED's (Flash Brightness Codes 0x88 - 0xAA)
30102848
30102849
LED Efficiency vs VIN
Dual LED's (Torch Brightness Codes 0x0F - 0xCF)
LED Efficiency vs VIN
Dual LED's (Torch Brightness Codes 0x00 - 0x04)
30102853
30102852
Closed loop Current Limit vs VIN
Closed loop Current Limit vs VIN
Flash Duration Register bits [6:5]=00 (Note 8)
Flash Duration Register bits [6:5]=01 (Note 8)
30102885
30102886
7
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Closed loop Current Limit vs VIN
Closed loop Current Limit vs VIN
Flash Duration Register bits [6:5]=10 (Note 8)
Flash Duration Register bits [6:5]=11 (Note 8)
30102887
30102888
Standby Current vs VIN
VHWEN=VIN, Enable Register = 0x18
Shutdown Current vs VIN
VHWEN= 0V
30102898
30102897
Non-Switching Current vs VIN
OVP Thresholds vs VIN (Note 9)
30102861
30102862
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Switching Frequency vs VIN
Indicator Currents vs VIN
Indicator Register Bits [2:0] = 0x00
30102863
30102867
Indicator Current vs VIN
Indicator Register Bits [2:0] = 0x02
Indicator Current vs VIN
Indicator Register Bits [2:0] = 0x07
30102868
30102876
ILED (Flash Mode) vs VIN
ILED (Flash Mode) vs VIN
LED1 and LED2 Connected Together
LED1 and LED2 Connected Together
(Upper 5 Flash Brightness Codes)
(Middle 5 Flash Brightness Codes)
30102872
30102873
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ILED (Torch Mode) vs VIN
ILED (Torch Mode) vs VIN
LED1 and LED2 Connected Together
LED1 and LED2 Connected Together
(Upper 4 Torch Brightness Codes)
(Lower 4 Torch Brightness Codes)
30102875
30102874
STROBE High to Flash LED Current
VIN Monitor Operation
30102882
30102877
VIN Flash Monitor Operation
NTC Mode Operation
30102883
30102884
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AET Mode Operation
HWEN Operation
Device Enabled in Flash Mode
30102878
30102879
TX1 Interrupt (Force Torch)
TX2 Interrupt (Force Shutdown)
TX2 Active High
30102880
30102881
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Block Diagram
30102805
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12
programming for the LED currents in either LED1 or LED2.
(See TORCH BRIGHTNESS REGISTER and FLASH
BRIGHTNESS REGISTER Descriptions.)
Overview
The LM3559 is a high-power white LED flash driver capable
of delivering up to 1.8A of LED current into a single LED, or
up to 900 mA into two parallel LEDs. The device incorporates
a 2MHz constant frequency, synchronous boost converter,
and two high side current sources to regulate the LED current
over the 2.5V to 5.5V input voltage range.
PASS MODE
At turn-on when the output voltage charges up to (VIN – 150
mV), the LM3559 will decide if the part operates in Pass Mode
or Boost mode. If the voltage difference between VOUT and
VLED is less than 270 mV, the device operates in Boost Mode.
If the difference between VOUT and VLED is greater than 270
mV, the device operates in Pass Mode. In Pass Mode the
boost converter stops switching, and the synchronous PFET
During operation when the output voltage is greater than VIN
– 150mV the boost converter switches and maintains at least
270 mV across both current sources (LED1 and LED2). This
minimum headroom voltage ensures that the current sinks
remain in regulation. When the input voltage rises above the
LED voltage + current source headroom voltage, the device
stops switching and turns the PFET on continuously (Pass
turns fully on bringing VOUT up to VIN – IIN x RPMOS (RPMOS
=
80 mΩ). In Pass Mode the inductor current is not limited by
the peak current limit. In this situation the output current must
be limited to 3A.
mode). In Pass mode the difference between (VIN - ILED
x
RON_P), and the voltage across the LEDs is dropped across
the current sources.
OVER-VOLTAGE PROTECTION
The output voltage is limited to typically 5V (5.075V max). In
situations such as the current source open, the LM3559 will
raise the output voltage in order to try to keep the LED current
at its target value. When VOUT reaches 5V the over-voltage
comparator will trip and turn off both the internal NFET and
PFET switches. When VOUT falls below 4.88V (typical), the
LM3559 will begin switching again.
Four hardware control pins provide control of the LM3559.
These include a hardware Flash Enable (STROBE), Dual
Flash Interrupt inputs (TX1 and TX2) designed to interrupt the
flash pulse during high-battery current conditions, and a logic
high hardware enable (HWEN) that can be pulled low to rapid-
ly place the device into shutdown. Additional features of the
LM3559 include an internal 4-bit ADC for LED voltage moni-
toring, an internal comparator for LED thermal sensing via an
external NTC thermistor, a battery voltage monitor during
flash current turn-on which monitors VIN and optimizes the
flash current during low-battery voltage conditions, an input
voltage monitor that can force Torch mode or LED shutdown
of the Flash current during input under voltage conditions, a
low-power Indicator current source with programmable pat-
terns, and a mode for utilizing the flash LEDs as a privacy
indicator.
Control of the LM3559 is done via an I2C-compatible inter-
face. This includes adjustment of the Flash and Torch current
levels, adjustment of the indicator LED currents and indicator
pattern, changing the Flash Timeout Duration, changing the
switch current limit, and reading back the ADC results. Addi-
tionally, there are 8 flag bits that indicate flash current timeout,
LED over-temperature, LED failure (by sensing LED short or
output OVP condition during Flash, Torch, or Privacy mode),
device thermal shutdown, VIN under-voltage condition, trip-
ping of the VIN Flash Monitor, and the occurrence of a TX
interrupt (both TX1 and TX2).
CURRENT LIMIT
The LM3559 features 4 selectable current limits: 1.4A, 2.1A,
2.7A, and 3.2A. These are programmable through the I2C-
compatible interface via bits [6:5] of the Flash Duration Reg-
ister. When the current limit is reached, the LM3559 stops
switching for the remainder of the switching cycle.
Since the current limit is sensed in the NMOS switch there is
no mechanism to limit the current when the device operates
in Pass Mode. In situations where there could potentially be
large load currents at OUT and the LM3559 is operating in
Pass mode, the load current must be limited to 3A. In Boost
mode or Pass mode, if VOUT falls below approximately 2.3V
the part stops switching, and the PFET operates as a current
source, limiting the current to typically 350 mA. This prevents
damage to the LM3559, and excessive current draw from the
battery during output short-circuit conditions.
FLASH MODE
In Flash mode the LED current sources (LED1 and LED2)
each provide 16 different current levels from typically 56.25
mA (total) to 1.8A (total) in steps of 56.25 mA. The Flash cur-
rents are adjusted via the Flash Brightness Register. Flash
mode is activated by writing a (1, 1) to bits [1:0] of the Enable
Register or by enabling the hardware flash input (STROBE)
via bit [2] of Configuration Register 1 and then pulling the
STROBE pin high (high polarity). Once the Flash sequence
is activated both current sinks (LED1 and LED2) will ramp up
to their programmed Flash current level by stepping through
all Torch and Flash levels (32 µs/step) until the programmed
current is reached.
STARTUP (ENABLING THE DEVICE)
Turn-on of the LM3559 is done through bits [1:0] of the Enable
Register. Bits [1:0] enable the device in Torch mode, Flash
mode, or Privacy Indicate mode. Additionally, bit 6 enables
the message indicator at the LEDI/NTC pin. On startup, when
VOUT is less than VIN, the internal synchronous PFET turns on
as a current source and delivers 350 mA to the output capac-
itor. During this time both current sources (LED1, and LED2)
are off. When the voltage across the output capacitor reaches
2.2V the active current sources can turn on. At turn-on the
current sources step through each FLASH and TORCH level
until their target LED current is reached (32 µs/step). This
gives the device a controlled turn-on and limits inrush current
from the VIN supply.
Bit [5] of the Enable Register (STROBE Level/Edge bit) de-
termines how the Flash pulse terminates. With the Level/
Edge bit = 1 the Flash current will only terminate when it
reaches the end of the Flash timeout period. With the Level/
Edge bit = 0, Flash mode can be terminated by pulling
STROBE low, programming bits [1:0] of the Enable Register
with (0,0), or by allowing the Flash timeout period to elapse.
If the Level/Edge bit = 0 and STROBE is toggled before the
end of the Flash timeout period the timeout period will reset.
Figure 1 and Figure 2 detail the Flash pulse termination for
the different Level/Edge bit settings.
INDEPENDENT LED CONTROL
Bits [4:3] of the Enable register provide for independent turn-
on and turn-off of the LED1 or LED2 current sources. The LED
current is adjusted by writing to the Torch Brightness or Flash
Brightness Registers. Both the Torch Brightness and the
Flash Brightness Register provide for independent current
13
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30102803
FIGURE 1. LED Current for STROBE (Level Triggered, Enable Register Bit [5] = 0)
STROBE Goes Low Before the End of the Programmed Timeout Duration
30102804
FIGURE 2. LED Current for STROBE (Edge Triggered, Enable Register Bit [5] = 1)
After the Flash pulse terminates; either by a flash timeout,
pulling STROBE low or disabling it via the I2C-compatible in-
terface, LED1 and LED2 turn completely off. This happens
even when Torch is enabled via the I2C-compatible interface,
and the Flash pulse is turned on by toggling STROBE. After
a Flash event ends, the EN1, EN0 bits (bits [1:0] of the Enable
Register) are automatically reset with (0, 0). The exception
occurs when the Privacy Terminate Bit is low (bit [3]) in the
Privacy Register. In this case, the specific current source that
is enabled for privacy mode will turn back on after the flash
pulse if Privacy mode had been enabled before the flash
pulse.
durations in steps of 32 ms giving a Flash timeout range of 32
ms to 1024 ms (see Table 5).
TORCH MODE
In Torch mode the current sources LED1 and LED2 each
provide 8 different current levels (Table 3). Torch mode is ac-
tivated by setting Enable Register bits [1:0] to (1, 0). Once
Torch mode is enabled, the current sources will ramp up to
the programmed Torch current level by stepping through all
of the Torch currents at (32 µs/step) until the programmed
Torch current level is reached.
PRIVACY INDICATOR MODE
FLASH TIMEOUT
The current sources (LED1 and/or LED2) can also be used
as a privacy indicator before and after flash mode. Privacy
indicate mode is enabled by setting the Enable Register bit
[1:0] to (0,1). Additionally, the Privacy Register contains the
bits to select which current source to use as the privacy indi-
cator (either LED1, LED2, or both), whether or not the privacy
The Flash Timeout period sets the amount of time that the
Flash Current is being sourced from current sources LED1
and LED2. Bits [4:0] of the Flash Duration Register set the
Flash Timeout period. There are 32 different Flash Timeout
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indicate mode turns off at the end of the flash pulse, and con-
tains the 8 intensity levels for the privacy indicator.
[2:0] of the Privacy Register allow for 8 different duty cycles
of 10%, 20%, 30%, 40%, 50%, 60%, 70%, and 80%. See
Table 14 for Privacy Register Bit settings. Figure 3 details the
timing for the Privacy Indicate Mode on ILED1 or ILED2.
The intensity of the LEDs in privacy indicate mode is set by
PWM’ing the lowest Torch current level (28.125 mA). Bits
30102806
FIGURE 3. Privacy Indicate Timing
POWER AMPLIFIER SYNCHRONIZATION (TX1)
pulled low before the Flash pulse terminates, the LED current
will return to the previous Flash current level. At the end of the
Flash timeout, whether the TX1/TORCH pin is high or low, the
current sources will turn off.
The TX1/TORCH/GPIO1 pin has a triple function. With Con-
figuration Register 1 Bit [7] = 0 (default) TX1/TORCH/GPIO1
is a Power Amplifier Synchronization input. This mode is de-
signed to reduce the flash LED current when TX1 is pulled
high (active high polarity) or low (active low polarity). When
the LM3559 is engaged in a Flash event and the TX1/TORCH
pin is pulled high, both LED1 and LED2 are forced into Torch
mode at the programmed Torch current setting. If TX1 is then
The polarity of the TX1 input can be changed from active high
to active low by writing a '0' to bit [5] of Configuration Register
1. With this bit set to ‘0’ the LM3559 will be forced into Torch
mode when TX1/TORCH is pulled low. Figure 4 details the
functionality of the TX1 Interrupt.
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30102807
FIGURE 4. TX1 or TX2 Interrupt Event
30102822
FIGURE 5. Hardware Torch Mode
TX2/INT/GPIO2
HARDWARE TORCH
With Configuration Register 1 Bit [7] = 1, TX1/TORCH is con-
figured as a hardware Torch mode enable. In this mode
(TORCH mode), a high at TX1/TORCH turns on the LED cur-
rent at the programmed Torch current setting. The STROBE
input and I2C Enabled flash takes precedence over TORCH
mode. In hardware torch mode, both LED1 and LED2 current
sources will turn off after a flash event and Configuration
Register 1 Bit [7] will be reset to 0. In this situation, to re-enter
torch mode via hardware torch, the hardware torch enable bit
(Configuration Register 1 Bit [7]) must be reset to 1. Figure
5 details the functionality of the TX1/TORCH/GPIO1 input.
The TX2/INT/GPIO2 pin has a triple function. In TX2 mode
(Default) the TX2/INT/GPIO2 pin is an active high Flash in-
terrupt. With GPIO Register bit [3] = 1 the TX2/INT/GPIO2 pin
is configured as general purpose logic I/O. With GPIO Reg-
ister bit [6] = 1, and with the TX2/INT/GPIO2 pin configured
as a GPIO2 output, the TX2/INT/GPIO2 pin is an interrupt
output.
TX2 MODE
In TX2 mode, when Configuration Register 1, bit [6] = 0, the
TX2/INT/GPIO2 pin has active low polarity. Under this condi-
tion when the LM3559 is engaged in a Flash event and TX2
is pulled low, both LED1 and LED2 are forced into Torch
mode. In TX2 mode with Configuration Register 1, bit [6] = 1
the TX2/INT/GPIO2 input has active high polarity. Under this
condition when the LM3559 is engaged in a Flash event and
the TX2/INT/GPIO2 pin is driven high, both LED1 and LED2
are forced into Torch mode. During a flash interrupt event if
the TX2/INT/GPIO2 input is disengaged the LED current will
GPIO1 MODE
With Bit [0] of the GPIO Register set to 1, the TX1/TORCH/
GPIO1 pin is configured as a logic I/O. In this mode the TX1/
TORCH/GPIO1 pin is readable and writable as a logic input/
output via bits [2:1] of the GPIO Register. See Table 9.
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return to the previous Flash current level. During a flash event,
if TX2 is active, the LED current sources will still turn off after
the Flash timeout. Figure 4 details the functionality of the TX2
Interrupt.
INTERRUPT OUTPUT (INT MODE)
The TX2/INT/GPIO2 pin can be reconfigured as an active low
interrupt output by setting bit [6] in the GPIO Register to ‘1’
and configuring TX2/INT/GPIO2 as a GPIO2 output. In this
mode, TX2/INT/GPIO2 will pull low when any of these condi-
tions exist.
TX2 Shutdown
TX2 also has the capability to force shutdown. Bit [0] of Con-
figuration Register 2 set to a '1' changes the TX2 mode from
a force Torch when active to a force shutdown when active.
For example, if TX2/INT/GPIO2 is configured for TX2 mode
with active high polarity, and bit [0] of Configuration Register
2 is set to '1' then when TX2 is driven high, the active current
sources (LED1 and/or LED2) will be forced into shutdown.
Once the active current sources are forced into shutdown by
activating TX2, the current sources can only be re-enabled if
TX2 is deactivated and the Flags Register is read back.
1. The LM3559 is configured for NTC mode (Configuration
Register 1 bit [4] = 1) and the voltage at LEDI/NTC has
fallen below VTRIP (1V typical).
2. The LM3559 is configured for VIN Monitor mode (VIN
Monitor Register bit [0] = 1) and VIN is below the
programmed VIN Monitor Threshold.
3. The LM3559 is configured for VIN Flash Monitor mode
(VIN Monitor Register bit [3] = 1) and VIN falls below the
programmed VIN Flash Monitor Threshold. Figure 6
details the functionality of the TX2/INT/GPIO2 input.
GPIO2 MODE
Once INT is pulled low due to any of the above conditions
having been met, INT will only go back high again if any of the
conditions are no longer true and the Flags Register is read.
With Bit [3] of the GPIO Register set to 1, the TX2/INT/GPIO2
pin is configured as a logic I/O. In this mode the TX2/INT/
GPIO2 pin is readable and writeable as a logic input/output
via bits [5:4] of the GPIO Register. See Table 9.
30102808
FIGURE 6. TX2 As an Interrupt Output (During an NTC Event)
INDICATOR LED/THERMISTOR (LEDI/NTC)
The Indicator Blinking Register controls the following (see
Table 17):
The LEDI/NTC pin serves a dual function, either as a pro-
grammable LED message indicator driver, or as a comparator
input for negative temperature coefficient (NTC) thermistors.
1. Number of blank periods (BLANK #). This has 16
settings. tBLANK = tACTIVE × BLANK# , where tACTIVE
tPERIOD × PERIOD#
=
MESSAGE INDICATOR CURRENT SOURCE (LEDI/NTC)
2. Pulse width (tPULSE) has 16 settings between 0 and 480
ms in steps of 32 ms. The pulse width is the duration
which the indicator current is at its programmed set point
at the end of the ramp-up time.
LEDI/NTC is configured as a message indicator current
source by setting Configuration Register 1 bit [4] = 0. The in-
dicator current source is enabled/disabled via Enable Regis-
ter bit [6]. Enable Register bit [7] programs the Message
Indictor for blinking mode. When the message indicator is set
for blinking mode the pattern programmed into the Indicator
Register and Indicator Blinking Register is sent to the Mes-
sage Indicator current source.
The Indicator Register controls the following (see Table 16):
1. Indicator current level (IIND). There are 8 message
indicator current levels from 2.25 mA to 18 mA in steps
of 2.25 mA.
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2. Number of periods (PERIOD #). This has 8 steps. A
period (tPERIOD) is found by (tPERIOD = tR + tF + 2 x
tPULSE). (See Figure 7 for indicator timing).
ms, 156 ms, 312 ms, and 624 ms are available. The ramp
times apply for both ramp-up and ramp-down and are not
independently changeable.
3. Ramp times (tR or tF) for turn-on and turn-off of the
indicator current source. Four programmable times of 78
30102812
FIGURE 7. Message Indicator Timing Diagram
Message Indicator Example 1 (Single Pulse with Dead
Time):
lows. tR = tF = 312 ms, tWIDTH = 192 ms (tPERIOD = 312 ms x 2
+ 192 ms x 2 = 1016 ms). BLANK# setting will be: 5s/1016
ms x 1 (PERIOD# = 1). Giving a BLANK# setting of 5. The
resulting waveform will appear as:
As an example, to set up the message indicator for a 312 ms
ramp-up and ramp-down, 192 ms pulse width, and 1 pulse
followed by a 5s delay. The indicator settings will be as fol-
30102813
FIGURE 8. Message Indicator Example 1
Message Indicator Example 2 (Multiple Pulses with Dead
Time):
tACTIVE time is tPERIOD × 3 = 1016 ms × 3 = 3048 ms. This
results in a blank time of tBLANK = tACTIVE × BLANK# = 3.048s
× 5 = 15.24s
Another example has the same tR, tF, tPULSE, and tBLANK times
as before, but this time the PERIOD# is set to 3. Now the
30102814
FIGURE 9. Message Indicator Example 2
Updating the Message Indicator
NTC MODE
The best way to update the message indicator is to disable
the Message Indicator output via the Enable Register bit [7],
write the new sequence to the Indicator Register and/or Indi-
cator Blinking Register, and then re-enable the Message
Indicator. Updating the Indicator Registers on the fly can lead
to long delays between pattern changes. This is especially
true if the PERIOD#, or BLANK# setting is changed from a
high setting to a lower setting.
Writing a (1) to Configuration Register 1 bit [4] configures the
LEDI/NTC pin for NTC mode. In this mode the indicator cur-
rent source is disabled and LEDI/NTC becomes the positive
input to the NTC comparator. NTC mode operates as a LED
current interrupt that is triggered when the voltage at LEDI/
NTC goes below 1V.
Two actions can be taken when the NTC comparator is
tripped. With Configuration Register 2 bit [1] set to ‘0’ the NTC
interrupt will force the LED current from Flash mode into Torch
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mode. With Configuration Register 2 bit [1] set to ‘1’ the NTC
interrupt will force the LED current into shutdown.
mode only during a Flash event. For example, if TX1/TORCH
goes high while the LED current is in Flash mode, the LEDs
will be forced into Torch mode only for the duration of the
timeout counter. At the end of the timeout counter the LEDs
will turn off.
Whether in NTC force torch or NTC shutdown, in order to re-
enter flash mode or torch mode after an NTC event, two things
must occur. First, the NTC input must be above the 1V thresh-
old. Secondly, the Flags Register must be read.
With Configuration Register 2 bit [2] set to (1) the LM3559 is
configured for AET mode and the operation of TX1/TORCH
becomes dependent on its occurrence relative to the
STROBE input. In this mode, if TX1/TORCH goes high first,
then STROBE goes high next, the LEDs are forced into Torch
mode with no timeout. In this mode, if TX1/TORCH goes high
after STROBE has gone high, then the TX1/TORCH pin op-
erates as a normal LED current interrupt and the LEDs will
turn off at the end of the timeout duration (see Figure 10 for
a detailed operation of this mode).
To avoid noise from falsely triggering the NTC Comparator,
this mode incorporates a 250 µs deglitch timer. With NTC
mode active, VLEDI/NTC must go below the trip point (VTRIP) and
remain below it, for 250 µs before the LEDs are forced into
Torch mode (or shutdown) and the NTC Flag is written.
ALTERNATE EXTERNAL TORCH (AET MODE)
Configuration Register 2 bit [2] programs the LM3559 for Al-
ternative External Torch mode. With this bit set to (0) (default)
TX1/TORCH is a flash current interrupt that forces Torch
30102810
FIGURE 10. AET Mode Timing
VIN MONITOR
or LED2) will either turn off or be forced into the Torch current
setting. To reset the LED current to its previous level, VIN must
go above the VIN Monitor threshold and the Flags register
must be read back. See Figure 11 for the VIN Monitor Timing
Waveform.
The LM3559 has an internal comparator at IN that monitors
the input voltage and can force the LED current into Torch
mode or into shutdown, if VIN falls below the programmable
VIN Monitor Threshold. Bit 0 in the VIN Monitor Register en-
ables or disables this feature. Bits [2:1] of the VIN Monitor
Register program the 4 adjustable thresholds of 2.9V, 3.0V,
3.1V, and 3.2V. Bit 3 in Configuration Register 2 selects
whether an undervoltage event forces Torch mode or forces
the LEDs off. See Table 13 for additional information. When
the VIN Monitor is active and VIN falls below the programmed
VIN Monitor threshold, the active current sources (LED1 and/
To avoid noise from falsely triggering the VIN Monitor, this
mode incorporates a 250 µs deglitch timer. With the VIN Mon-
itor active, VIN must go below the VIN Monitor Threshold
(VIN_TH) and remain below it for 250 µs before the LEDs are
forced into Torch mode (or shutdown) and the VIN Monitor
Flag is written.
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30102809
FIGURE 11. VIN Monitor Waveform
VIN FLASH MONITOR (FLASH CURRENT RISING)
below the VIN Flash Monitor Threshold (VIN_FLASH) and re-
main below it for 8 µs before the flash current ramp is halted
and the VIN Flash Monitor Flag is written.
A second comparator at IN is available to monitor the input
voltage during the flash current turn-on. Bit [3] of the VIN
Monitor Register enables/disables this feature. With this bit
set to ‘1’ the VIN Flash Monitor is active. Bits [5:4] of the VIN
Monitor Register program the 4 selectable thresholds of
(2.9V, 3.0V, 3.1V, and 3.2V). The feature operates as follows:
during flash current turn-on the active current sources (LED1
and/or LED2) will transition through each of the lower flash
and torch current levels until the target flash current is
reached. With the VIN Flash Monitor active, if during the flash
current turn-on, the input voltage falls below the VIN Flash
Monitor threshold, the flash current is set to the level that the
current ramp had risen to at the time of the undervoltage
event. The Input Voltage Flash Monitor only operates during
the ramping up of the flash LED current.
LAST FLASH REGISTER
Once the VIN Flash Monitor is tripped, the flash code that
corresponded to the LED current at which the flash current
ramp was halted is written to the Last Flash Register. The Last
Flash Register is a read-only register; the lower 4 bits are
available to latch the code for LED1 and the upper 4 bits to
latch the code for LED2.
For example, suppose that the LM3559 is set up for a single
LED with a target flash current of 1125 mA. The VIN Flash
Monitor is enabled with the VIN Flash Monitor threshold set
to 3.0V (VIN Monitor Register bits [5:4] = 0, 1). When the
STROBE input is brought high, the LED current begins ramp-
ing up through the torch and flash codes at 32 µs/code. As
the input current increases, the input voltage at the LM3559’s
IN pin begins to fall due to the source impedance of the bat-
tery. By the time the LED current has reached 900 mA (code
0x77 or 450 mA per current source), VIN falls below 3.0V. The
VIN Flash Monitor will then stop the flash current ramp and
the LM3559 will continue to proceed with the flash pulse, but
at 900 mA instead of 1125 mA. Figure 12 details this se-
quence.
The VIN Flash Monitor ignores the first 2 flash codes during
the flash pulse turn on. As a result, if the VIN Flash Monitor is
enabled and VIN were to fall below the VIN Flash Threshold
as the LED current ramps up through either of the first two
levels, then the flash pulse would not be halted until code #3
(168.75 mA per current source).
To avoid noise from falsely triggering the VIN Flash Monitor,
this mode incorporates an 8 µs deglitch timer as well as an
internal analog filter at the input of the VIN Flash Monitors
Comparator. With the VIN Flash Monitor active, VIN must go
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30102815
FIGURE 12. VIN Flash Monitor Example
LED VOLTAGE MONITOR
this bit is set high the EOC bit (bit [6]) goes low and a con-
version is performed. When the conversion is complete, the
EOC bit goes high again. Subsequent conversions are per-
formed in manual mode by reading back the VLED Monitor
register, which resets the EOC bit and starts another conver-
sion (see Figure 14).
The LM3559 includes a 4-bit ADC which monitors the LED
forward voltage (VLED) and stores the digitized value in bits
[3:0] of the VLED Monitor Register. The highest voltage of
VLED1 or VLED2 is automatically sensed and that becomes
the sample point for the ADC. Bit 5, the ADC shutdown bit,
enables/disables the ADC with the default state set to enable
(bit [5] = 0).
ADC DELAY
The ADC Delay register provides for a programmable delay
from 250 µs to 8 ms, in steps of 250 µs. This delay is the delay
from when the EOC bit goes low to when the VLED Monitor
samples the LED voltage. In Automatic Mode the EOC bit
goes low when the Flash LED current hits its target. In Manual
mode the EOC bit goes low at the end of a readback of the
VLED Monitor Register (or when the manual mode bit (bit 4)
is re-written with a 1). Figure 13 and Figure 14 detail the timing
of the VLED Monitor for both Automatic mode and Manual
mode.
AUTOMATIC CONVERSION MODE
With the ADC enabled, a conversion is performed each time
a flash pulse is started. When a flash pulse is started bit [6] of
the VLED Monitor Register (End of Conversion bit) is auto-
matically written with a ‘0’. At the end of the conversion, bit [6]
will go high signaling that the VLED data is valid. A read back
of the VLED Monitor register will clear the EOC bit. Figure
13 details the VLED Monitor Automatic Conversion.
MANUAL CONVERSION MODE
The VLED Monitor can be set up for manual conversion mode
by setting bit [4] of the VLED Monitor Register to '1'. When
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30102821
FIGURE 13. VLED Monitor Automatic Mode
30102823
FIGURE 14. VLED Monitor Manual Mode
FLAGS REGISTER AND FAULT INDICATORS
THERMAL SHUTDOWN
Eight fault flags are available in the LM3559. These include:
a Flash Timeout, a Thermal Shutdown, an LED Failure Flag
(LEDF), an LED Thermal Flag (NTC), a VIN Monitor Flag, and
a VIN Flash Monitor Flag. Additionally, two LED interrupt flag
bits (TX1 interrupt and TX2 interrupt) are set when the corre-
sponding interrupt is activated. Reading back a "1" indicates
the flagged event has happened. A read of the Flags Register
resets these bits.
When the LM3559’s die temperature reaches +150°C, the
boost converter shuts down, and the NFET and PFET turn off.
Additionally, the active current source (LED1 and/or LED2)
turn off. When the thermal shutdown threshold is tripped a (1)
gets written to bit [1] of the Flags Register (Thermal Shutdown
bit). The LM3559 will not start up again until the die temper-
ature falls to below +135°C and the Flags Register is read
back, or when the device is shut down and started up again.
FLASH TIMEOUT
LED FAULT
The Timeout or (TO flag), (bit [0] of the Flags Register), reads
back a (1) if the LM3559 is active in Flash mode and the
Timeout period expires before the Flash pulse is terminated.
The flash pulse can be terminated before the Timeout period
expires by pulling the STROBE pin low (with Enable Register
bit [5] = 0), or by writing a (0,0) to bits [1:0] of the Enable
Register. The TO flag is reset to (0) by pulling HWEN low,
removing power to the LM3559, reading the Flags Register,
or when the next Flash pulse is triggered.
The LED Fault flag (bit 2 of the Flags Register) reads back a
(1) if the part is active in Flash or Torch mode and either LED1
or LED2 experience an open or short condition. An LED open
condition is signaled if the OVP threshold is crossed at the
OUT pin while the device is in Flash or Torch mode. An LED
short condition is signaled if the voltage at LED1 or LED2 goes
below 500 mV while the device is in Torch or Flash mode. In
an LED open condition there is a 2 µs deglitch time from when
the output voltage crosses the OVP threshold to when the
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LED Fault Flag is triggered. In an LED short condition there
is a 250 µs deglitch time before the LED Fault Flag is set. The
LED Fault Flag can only be reset to (0) by pulling HWEN low,
doing a power on reset of the LM3559, or by removing the
fault condition and reading back the Flags Register.
VTRIP (1V typical). When this has happened and the LM3559
has been forced into Torch mode or LED shutdown (depend-
ing on the state of Configuration Register 2 bit [1), the Flags
Register must be read, and the voltage at NTC must go above
1V in order to place the device back in normal operation. (See
NTC MODE section for more details).
TX1 AND TX2 INTERRUPT FLAGS
INPUT VOLTAGE FLASH MONITOR FAULT
The TX1 and TX2 interrupt flags (bits [3] and [4]) indicate an
interrupt event has occurred on the respective TX inputs. Bit
3 will read back a (1) if TX1 is in TX mode and there has been
a TX1 event since the last read of the Flags Register. Bit 4
will read back a (1) if TX2 is in TX mode and there has been
a TX2 event since the last read of the Flags Register. A read
of the Flags Register automatically resets these bits. A TX
event on TX1 or TX2, can be a high-to-low transition or a low-
to-high transition depending on the setting of the TX1 and TX2
polarity bits (see Configuration Register 1 Bits [6:5]).
The VIN Flash Monitor Flag (bit [6] of the Flags Register) reads
back a '1' when the Input Voltage Flash Monitor is enabled
and VIN falls below the programmed VIN Flash Monitor
threshold. This flag must be read back in order to resume
normal operation after the LED current has been forced to the
lower flash current setting.
INPUT VOLTAGE MONITOR FAULT
The VIN Monitor Flag (bit [7] of the Flags Register) reads back
a '1' when the Input Voltage Monitor is enabled and VIN falls
below the programmed VIN Monitor threshold. This flag must
be read back and VIN must go above the VIN Monitor thresh-
old in order to resume normal operation.
LED THERMAL FAULT (NTC Flag)
The NTC flag (bit [5] of the Flags Register) reads back a '1' if
the LM3559 is active in Flash or Torch mode, the device is in
NTC mode, and the voltage at LEDI/NTC has fallen below
I2C-Compatible Interface
START AND STOP CONDITIONS
The LM3559 is controlled via an I2C-compatible interface.
START and STOP conditions classify the beginning and end
of the I2C session. A START condition is defined as SDA
transitioning from HIGH to LOW while SCL is HIGH. A STOP
condition is defined as SDA transitioning from LOW to HIGH
while SCL is HIGH. The I2C master always generates the
START and STOP conditions.
30102818
FIGURE 15. Start and Stop Sequences
The I2C bus is considered busy after a START condition and
free after a STOP condition. During data transmission the
I2C master can generate repeated START conditions. A
START and a repeated START condition are equivalent func-
tion-wise. The data on SDA must be stable during the HIGH
period of the clock signal (SCL). In other words, the state of
SDA can only be changed when SCL is LOW. Figure 16
shows the SDA and SCL signal timing for the I2C-Compatible
Bus. See the Electrical Characteristics Tables for timing
values.
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30102819
FIGURE 16. I2C-Compatible Timing
I2C-COMPATIBLE CHIP ADDRESS
The device address for the LM3559 is 1010011 (0xA7 for read
and 0xA6 for write)). After the START condition, the I2C mas-
ter sends the 7-bit address followed by an eighth read or write
bit (R/W). R/W = 0 indicates a WRITE and R/W = 1 indicates
a READ. The second byte following the device address se-
lects the register address to which the data will be written. The
third byte contains the data for the selected register.
30102820
FIGURE 17. Device Address
TRANSFERRING DATA
Every byte on the SDA line must be eight bits long, with the
most significant bit (MSB) transferred first. Each byte of data
must be followed by an acknowledge bit (ACK). The acknowl-
edge related clock pulse (9th clock pulse) is generated by the
master. The master releases SDA (HIGH) during the 9th clock
pulse (write mode). The LM3559 pulls down SDA during the
9th clock pulse, signifying an acknowledge. An acknowledge
is generated after each byte has been received.
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Register Descriptions
TABLE 1. LM3559 Internal Registers
Register Name
Enable
Internal Hex Address
Power On/RESET Value
0x10
0x11
0x12
0x13
0x14
0x20
0x30
0x31
0x80
0x81
0xA0
0xB0
0xC0
0xD0
0xE0
0xF0
0x18
0x58
0x00
0x00
0xF0
0x80
0x80
0xC0
0xC0
0x00
0x52
0xDD
0x6F
0x00
0x68
0xF0
Privacy
Indicator
Indicator Blinking
Privacy PWM
GPIO
VLED Monitor (ADC)
ADC Delay
VIN Monitor
Last Flash
Torch Brightness
Flash Brightness
Flash Duration
Flags
Configuration 1
Configuration 2
ENABLE REGISTER
Bit [5] sets the level or edge control for the STROBE input.
Bits 7 and 6 control the Indicator current source (see Table
2).
Bits [1:0] of the Enable Register controls the on/off state of
Torch mode, Flash mode, and Privacy Indicate mode. Bits
[4:3] turn on/off the main current sources (LED1 and LED2).
TABLE 2. Enable Register Descriptions
Bit 7
Bit 6
Bit 5
Bit 4 Bit 3
Bit 2
Bit 1
Bit 0
(EN Blink)
(EN
Message
Indicator)
(STROBE
Level/Edge)
(LED2 (LED1
Enable) Enable)
(Not Used) (EN1)
(EN0)
0 = Message 0 = Message 0 = (Level Sensitive) 0 = LED2 off 0 = LED1 off N/A
Enable Bits
Indicator
Blinking
Function is
Indicator is
disabled
(default)
When STROBE goes 1 = LED2 on 1 = LED1 on
00 = Current Sources are
Shutdown (default)
01 = Privacy Indicator Mode
10 = Torch Mode
high, the flash current (default)
(default)
will turn on and remain
disabled (See 1= Message on for the duration the
Note below). Indicator is
STROBE pin is held
high or until the Flash
Timeout occurs,
whichever comes first.
(default)
11 = Flash Mode (bits reset
at timeout)
(default)
1 = Message
Indicator
Blinking
enabled.
Function is
enabled. The
message
indicator
blinks the
pattern
1 = (Edge Triggered)
When STROBE goes
high , the flash current
will turn on and remain
on for the duration of
the Flash timeout.
programmed
in the
Indicator
Register and
Indicator
Blinking
Register
Note: Bit 7 Enables/Disables the Message Indicator Blinking Function. With this bit set to 0 and Bit 6 set to 1, the Message Indicator turns on constantly at the
programmed current as set in the Indicator Register, bits [2:0].
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TORCH BRIGHTNESS REGISTER
Bits [2:0] of the Torch Brightness Register set the Torch cur-
rent for LED1. Bits [5:3] set the Torch current for LED2. (see
Table 3).
TABLE 3. Torch Brightness Register Descriptions
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
(N/A)
(N/A)
(TC2A)
(TC2B)
(TC2C)
(TC1A)
(TC1B)
(TC1C)
(Not Used)
LED2 Torch Current Select Bits
000 = 28.125 mA (56.25 mA total)
001 = 56.25 mA (112.5 mA total)
LED1 Torch Current Select Bits
000 = 28.125 mA (56.25 mA total)
001 = 56.25 mA (112.5 mA total)
010 = 84.375 mA (168.75 mA total) default 010 = 84.375 mA (168.75 mA total) default
011 = 112.5 mA (225 mA total)
100 = 140.625 mA (281.25 mA total)
101 = 168.75 mA (337.5 mA total)
110 = 196.875 mA (393.75 mA total)
111 = 225 mA (450 mA total)
011 = 112.5 mA (225 mA total)
100 = 140.625 mA (281.25 mA total)
101 = 168.75 mA (337.5 mA total)
110 = 196.875 mA (393.75 mA total)
111 = 225 mA (450 mA total)
FLASH BRIGHTNESS REGISTER
Bits [3:0] of the Flash Brightness Register set the Flash cur-
rent for LED1. Bits [7:4] set the Flash current for LED2. (see
Table 4).
TABLE 4. Flash Brightness Register Descriptions
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
(FC2A)
(FC2B)
(FC2C )
(FC2D)
(FC1A )
(FC1B)
(FC1C)
(FC1D)
LED2 Flash Current Select Bits
0000 = 56.25 mA (112.5 mA total)
0001 = 112.5 mA (225 mA total)
0010 = 168.75 mA (337.5 mA total)
0011 = 225 mA (450 mA total)
LED1 Flash Current Select Bits
0000 = 56.25 mA (112.5 mA total)
0001 = 112.5 mA (225 mA total)
0010 = 168.75 mA (337.5 mA total)
0011 = 225 mA (450 mA total)
0100 = 281.25 mA (562.5 mA total)
0101 = 337.5 mA (675 mA total)
0110 = 393.75 mA (787.5 mA total)
0111 = 450 mA (900 mA total)
0100 = 281.25 mA (562.5 mA total)
0101 = 337.5 mA (675 mA total)
0110 = 393.75 mA (787.5 mA total)
0111 = 450 mA (900 mA total)
1000 = 506.25 mA (1012.5 mA total)
1001 = 562.5 mA (1125 mA total)
1010 = 618.75 mA (1237.5 mA total)
1011 = 675 mA (1350 mA total)
1100 = 731.25 mA (1562.5 mA total)
1101 = 787.5 mA (1575 mA total) Default
1110 = 843.75 mA (1687.5 mA total)
1111 = 900 mA (1800 mA total)
1000 = 506.25 mA (1012.5 mA total)
1001 = 562.5 mA (1125 mA total)
1010 = 618.75 mA (1237.5 mA total)
1011 = 675 mA (1350 mA total)
1100 = 731.25 mA (1562.5 mA total)
1101 = 787.5 mA (1575 mA total) Default
1110 = 843.75 mA (1687.5 mA total)
1111 = 900 mA (1800 mA total)
www.national.com
26
FLASH DURATION REGISTER
Bits [4:0] of the Flash Duration Register set the Flash Timeout
duration. Bits [6:5] set the switch current limit. (see Table 5).
TABLE 5. Flash Duration Register Descriptions
Bit 7
(Not used)
Bit 6
(CL1)
Bit 5
(CL0)
Bit 4
(T4)
Bit 3
(T3)
Bit 2
(T2)
Bit 1
(T1)
Bit 0
(T0)
N/A
Current Limit Select Bits
Flash timeout Select Bits
00 = 1.4A Peak Current Limit 00000 = 32 ms timeout
01 = 2.1A Peak Current Limit 00001 = 64 ms timeout
10 = 2.7A Peak Current Limit 00010 = 96 ms timeout
11 = 3.2A Peak Current Limit 00011 = 128 ms timeout
(default)
00100 = 160 ms timeout
00101 = 192 ms timeout
00110 = 224 ms timeout
00111 = 256 ms timeout
01000 = 288 ms timeout
01001 = 320 ms timeout
01010 = 352 ms timeout
01011 = 384 ms timeout
01100 = 416 ms timeout
01101 = 448 ms timeout
01110 = 480 ms timeout
01111 = 512 ms timeout (default)
10000 = 544 ms timeout
10001 = 576 ms timeout
10010 = 608 ms timeout
10011 = 640 ms timeout
10100 = 672 ms timeout
10101 = 704 ms timeout
10110 = 736 ms timeout
10111 = 768 ms timeout
11000 = 800 ms timeout
11001 = 832 ms timeout
11010 = 864 ms timeout
11011 = 896 ms timeout
11100 = 928 ms timeout
11101 = 960 ms timeout
11110 = 992 ms timeout
11111 = 1024 ms timeout
27
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FLAGS REGISTER
The Flags Register holds the flag bits indicating: Flash Time-
out, Thermal Shutdown, LED Fault (Open or Short), TX In-
terrupts (TX1 and TX2), LED Thermal Fault (NTC), VIN
Monitor Trip, and VIN Flash Monitor Trip. All Flags are cleared
on read back of the Flags Register. (see Table 6).
TABLE 6. Flags Register Descriptions
Bit 7
(VIN Monitor)
Bit 6
(VIN Flash
Monitor)
Bit 5
(NTC Fault)
Bit 4 Bit 3
(TX2
Interrupt)
Bit 2
(TX1 Interrupt ) (LED Fault)
Bit 1
(Thermal
Shutdown)
Bit 0
(Flash
timeout)
0 = VIN is
VIN did not fall 0 = LEDI/NTC 0 = TX2 has
0 = TX1 has not 0 = Proper
0 = Die
0 = Flash
below the VIN pin is above
Flash Monitor 1V(default)
threshold
during the
flash pulse
turn-on or VIN
Flash Monitor
is disabled
not changed
state (default) (default)
changed state
LED
Operation
(default)
Temperature timeout did not
above the VIN
Monitor
Threshold or
VIN Monitor
Threshold is
Disabled
below
expire
Thermal
(default)
Shutdown
Limit (default)
(default)
(default)
1 = VIN
Monitor is
enabled and
1 = VIN Flash 1 = NTC mode 1 = TX2 has
Monitor is
enabled and
1 = TX1 has
is enabled and changed state changed state
LEDI/NTC has (TX2 mode (TX1 mode only) or Short)
only)
1 = LED
1 = Die
1 = Flash
Failed (Open Temperature timeout
has crossed
the Thermal
Shutdown
Expired
VIN has fallen VIN fell below fallen below
1V
below the
the
Threshold
programmed programmed
threshold
VIN Flash
Monitor
threshold
during the
flash pulse
turn-on
CONFIGURATION REGISTER 1
Configuration Register 1 holds the STROBE Input Enable bit,
lection bits for TX1 and TX2, and the Hardware Torch Enable
the STROBE polarity bit, the NTC Enable bit, the polarity se-
bit (see Table 7).
TABLE 7. Configuration Register 1 Descriptions
Bit 7
Bit 6
Bit 5 Bit 4 Bit 3 Bit 2
Bit 1
Bit 0
(Hardware (TX2 Polarity) (TX1 Polarity) (NTC Mode
(STROBE
Polarity)
(STROBE
Input Enable)
(Not Used)
(Not Used)
Torch Mode
Enable)
Enable)
0 = TX1/
TORCH is a
TX input
0 = TX2 is
configured for configured for pin is
active low
polarity
0 = TX1 is
0 = LEDI/NTC 0 = STROBE 0 = STROBE N/A
Input Enable is Pin disabled
configured as active low. (default)
N/A
active low
polarity
(default)
an indicator
output
Pulling
STROBE low
will turn on
Flash current
(default)
1 = TX1/
1 =TX2 pin is 1 = TX1 is
1 = LEDI/NTC 1 = STROBE 1 = STROBE
TORCH pin is configured for configured for is configured Input is active Input enabled
a hardware
TORCH
enable. This
bit is reset to 0
after a flash
event.
active high
polarity
(default)
active high
polarity
(default)
as a
high. Pulling
STROBE high
will turn on
Flash current
(default)
comparator
input for an
NTC
thermistor
www.national.com
28
CONFIGURATION REGISTER 2
mode enable bit, and the VIN Monitor Shutdown bit (see Table
8).
Configuration Register 2 holds the TX2 shutdown select bit,
the NTC shutdown select bit, the Alternate External Torch
TABLE 8. Configuration Register 2 Bit Descriptions
Bit 7
(Not used)
Bit 6
(Not used)
Bit 5 Bit 4 Bit 3 Bit 2
Bit 1
(NTC
Shutdown)
Bit 0
(TX2
Shutdown)
(Not used) (Not used) (VIN Monitor (AET mode)
Shutdown)
0 = VIN falling 0 = AET
N/A
N/A
N/A
N/A
0 = Voltage at
LEDI/NTC
falling below
0 = TX2 event
will force the
LED current to
Mode
below the
Disabled
(default)
programmed
VIN Monitor
Threshold will
force the LED
current into the
programmed
torch current
(default)
VTRIP will force the
programmed
torch current
(default)
the active
current source
(LED1 and/or
LED2) to the
programmed
torch current.
(default)
1 = VIN falling 1 = AET
1 = Voltage at
LEDI/NTC
falling below
VTRIP will force into shutdown.
the active
current source
1 = TX2 event
will force the
LED current
Mode
below the
Enabled
programmed
VIN Monitor
Threshold will
force the LED
current into
shutdown.
(either LED1
and/or LED2)
into shutdown.
29
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GPIO REGISTER
The GPIO register contains the control bits which change the
state of the TX1/TORCH/GPIO1 pin and the TX2/INT/GPIO2
pins to general purpose I/O’s (GPIO’s). Additionally, bit 6 of
this register contains the interrupt configuration bit. Table 9
describes the bit description and functionality of the GPIO
register. To configure the TX1 or TX2 pins as GPIO outputs
an initial double write is required to register 0x20. For exam-
ple, to configure TX2 to output a logic high, an initial write of
0xB8 would need to occur twice, to force GPIO2 low. Subse-
quent writes to GPIO2 after the initial set-up only requires a
single write. To read back the GPIO inputs, a write, then a
read, of register 0x20 must occur each time the data is read.
For example, if GPIO2 is set up as a GPIO input and the
GPIO2 input has then changed state, first a write to 0x20 must
occur, then the following readback of register 0x20 will show
the updated data. When configuring TX2 as an interrupt out-
put, the TX2/GPIO2/INT pin must first be configured as a
GPIO output (double write). For example, to configure TX2/
GPIO2/INT for INT mode, a write of 0xF8 to register 0x20
must be done twice.
TABLE 9. GPIO Register
Bit 7
(Not
Used)
Bit 6
Bit 5
Bit 4
(TX2/INT/
Bit 3
Bit 2
Bit 1
Bit 0
(TX2/INT/GPIO2 (TX2/INT/
Interrupt
Enable)
(TX2/INT/
GPIO2
Control)
(TX1/TORCH/ (TX1/TORCH/ (TX1/TORCH/
GPIO1 data)
GPIO2 data) GPIO2 data
direction)
GPIO1 data
direction)
GPIO1
Control)
N/A
0 = TX2/INT/
GPIO2 is
configured
according to bit 3 GPIO2 pin in (default)
of this register
This bit is the 0 = TX2/INT/
read or write GPIO2 is a
0 = TX2/INT/
GPIO is a TX2 read or write
interrupt
(default)
This bit is the 0 = TX1/
0 = TX1/
TORCH/GPIO1 TORCH/
is a GPIO input GPIO1 pin is
data for the
GPIO Input
data for the
GPIO1 pin in
GPIO mode
(default)
configured
GPIO mode
according to
Configuration
Register 1 bit
[7] (default)
(default)
1 = with bits [4:3]
= 11, TX2/INT/
GPIO2 is an
interrupt output.
See Interrupt
section.
1 = TX2/INT/
GPIO2 is a
GPIO Output
1 = TX2/INT/
GPIO2 is
configured as a
GPIO
1 TX1/
1 = TX1/
TORCHGPIO1 TORCH/
is an output GPIO1 pin is
configured as a
GPIO
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30
LAST FLASH REGISTER
The Last Flash Register is updated at the same time that the
corresponding Flag bit is written to the Flags Register. This
results in a delay of 250 µs from when VLEDI/NTC (NTC mode)
crosses VTRIP, or VIN (VIN Monitor enabled) crosses the
VIN_TH. During VIN Flash Monitor there is a 8 µs deglitch time
so the VIN Flash Monitor Flag is written (and the Last Flash
The Last Flash Register is a read only register which is loaded
with the flash code corresponding to the flash level that the
LM3559 was at if any of the following events happens:
1. Voltage at LEDI/NTC falling below VTRIP with the device
in NTC mode (Configuration Register 1 bit [4] = 1)
Register is updated) 8 µs after VIN falls below VIN_FLASH
.
2. Input voltage falling below the programmed VIN Monitor
Threshold with device in VIN Monitor mode (VIN Monitor
Register bit [0] = 1)
3. Input voltage falling below the programmed VIN Flash
Monitor Threshold with the device in VIN Flash Monitor
mode (VIN Monitor Register bit [3] = 1).
TABLE 10. Last Flash Register Descriptions
Bit 7
(LF2A)
Bit 6
(LF2B)
Bit 5 Bit 4 Bit 3 Bit 2
(LF2C) (LF2D) (LF1A) (LF1B)
Bit 1
(LF1C)
Bit 0
(LF1D)
These bits are read only and represent the Flash Current
These bits are read only and represent the Flash Current Code for
Code for LED2 that the LM3559 was at during the interrupt. LED1 that the LM3559 was at during the interrupt.
0000 = 56.25 mA (112.5 mA total)
0001 = 112.5 mA (225 mA total)
0010 = 168.75 mA (337.5 mA total)
0011 = 225 mA (450 mA total)
0000 = 56.25 mA (112.5 mA total)
0001 = 112.5 mA (225 mA total)
0010 = 168.75 mA (337.5 mA total)
0011 = 225 mA (450 mA total)
0100 = 281.25mA (562.5 mA total)
0101 = 337.5 mA (675 mA total)
0110 = 393.75 mA (787.5 mA total)
0111 = 450 mA (900 mA total)
0100 = 281.25mA (562.5 mA total)
0101 = 337.5 mA (675 mA total)
0110 = 393.75 mA (787.5 mA total)
0111 = 450 mA (900 mA total)
1000 = 506.25 mA (1012.5 mA total)
1001 = 562.5 mA (1125 mA total)
1010 = 618.75 mA (1237.5 mA total)
1011 = 675 mA (1350 mA total)
1100 = 731.25 mA (1562.5 mA total)
1101 = 787. 5mA (1575 mA total)
1110 = 843.75 mA (1687.5 mA total)
1111 = 900 mA (1800 mA total)
1000 = 506.25 mA (1012.5 mA total)
1001 = 562.5 mA (1125 mA total)
1010 = 618.75 mA (1237.5 mA total)
1011 = 675 mA (1350 mA total)
1100 = 731.25 mA (1562.5 mA total)
1101 = 787. 5mA (1575 mA total)
1110 = 843.75 mA (1687.5 mA total)
1111 = 900 mA (1800 mA total)
31
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VLED MONITOR REGISTER
sion is still performed. In automatic conversion mode a
conversion is performed each time a flash pulse is initiated.
Bit [5] is the ADC shutdown bit. Bit [6] signals the end of con-
version. This is a read-only bit that goes high when a conver-
sion is complete and data is ready. A read of the VLED
Monitor Register clears the End of Conversion bit (see ).
The VLED Monitor Register controls the internal 4-bit analog
to digital converter. Bits [3:0] of this register contain the 4-bit
data of the LED voltage. This data is the digitized voltage of
the highest of either VLED1 to GND or VLED2 to GND. Bit [4]
is the Manual Mode enable which provides for a manual con-
version of the ADC. In Manual Mode the Automatic Conver-
TABLE 11. VLED Monitor Register Descriptions
Bit 7
(Not
Bit 6
(End of
Bit 5
(Shutdown)
Bit 4 Bit 3 Bit 2
(Manual Mode (ADC3) (ADC2)
Bit 1
(ADC1)
Bit 0
(ADC0)
Used) Conversion)
N/A 0 = Conversion in
progress(default)
Enable)
0 = ADC is
enabled
(default)
0 = Manual
Mode Disabled
(default)
0000 = (VLED < 3.2V) (default)
0001 = (3.2V ≤ VLED < 3.3V)
0010 = (3.3V ≤ VLED < 3.4V)
0011 = (3.4V ≤ VLED < 3.5V)
0100 = (3.5V ≤ VLED < 3.6V)
0101 = (3.6V ≤ VLED < 3.7V)
0110 = (3.7V ≤ VLED < 3.8V)
0111 = (3.8V ≤ VLED < 3.9V)
1000 = (3.9V ≤ VLED < 4.0V)
1001 = (4.0V ≤ VLED < 4.1V)
1010 = (4.1V ≤ VLED < 4.2V)
1011 = (4.2V ≤ VLED < 4.3V)
1100 = (4.3V ≤ VLED < 4.4V)
1101 = (4.4V ≤ VLED < 4.5V)
1110 = (4.5V ≤ VLED < 4.6V)
1111 = (4.6V ≤ VLED)
1 = Conversion done 1 = ADC is
shutdown, no
1 = Manual
Mode is Enabled
conversion is
performed
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32
ADC DELAY REGISTER
applies to both Manual Mode and Automatic Mode. Bit 5 is
the No-Delay bit and can set the delay to effectively 0. (See
Table 12, Figure 13, and Figure 14.)
The ADC Delay Register programs the delay from when the
EOC bit goes low to when a conversion is initiated. This delay
TABLE 12. ADC Delay Register
Bit 4 (D1) Bit 3 (D2)
Bit 7
(Not
Bit 6
(Not used)
Bit 5 (No Delay)
Bit 2 (D3) Bit 1 (D4)
Bit 0 (D5)
Used)
0 = Delay is set by bits [4:0]
Bits [4:0] programs the delay from when the EOC bit goes low to when
(default)
a conversion is started (250 µs/step).
00000 = 250 µs (default)
:
:
1 = no delay from when the EOC
goes low to when the conversion is
started.
N/A
:
:
11111 = 8ms
INPUT VOLTAGE MONITOR REGISTER
bit for the VIN Flash Monitor, and the threshold select for the
VIN Flash Monitor (see Table 13).
The VIN Monitor Register contains the Enable bit for the VIN
Monitor, the threshold select for the VIN Monitor, the enable
TABLE 13. VIN Monitor Register
Bit 7
Bit 6
Bit 5
Bit 4 Bit 3
Bit 2
Bit 1
Bit 0
(Not used)
(Not used)
(VIN Flash
Monitor
Threhold 1) Threhold 0)
(VIN Flash (VIN Flash
Monitor
(VIN Monitor (VIN Monitor
Threshold 1) Threshold 0)
(VIN Monitor
Enable)
Monitor
Enable)
N/A
00= 2.9V (default)
01 = 3.0V
10 = 3.1V
0 = VIN Flash 00 = 2.9V (default)
0 = VIN Monitor
disabled (default)
Monitor is
disabled
(default)
01= 3.0V
10 = 3.1V
11 = 3.2V
11 = 3.2V
1 = VIN Flash
Monitor is
enabled
1 = VIN Monitor
enabled
PRIVACY REGISTER
after the flash pulse terminates, and the duty cycle settings
(between 10% and 80%) for setting the privacy LED current
(see Table 14).
The Privacy Register contains the bits to control which current
source is used for the privacy indicator (LED1 or LED2 or
both), whether the privacy indicator turns off or remains on
TABLE 14. Privacy Register
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2 (PD2)
Bit 1 (PD1)
Bit 0 (PD0)
(Blink 2)
(Blink 1)
(LED2
Privacy)
(LED1
Privacy)
(Privacy
Terminate)
00 = No Blinking
01 = 128 ms Blink Period
(default)
0 = LED2 is off 0 = LED1 is off 0 = Privacy
Privacy mode current levels (% of minimum
torch current)
for privacy
mode
for privacy
mode
mode turns
back on at the 000 = 10% (default)
10 = 256 ms Blink Period
11 = 512 ms Blink Period
(default)
1 = LED2 is on for privacy
for privacy
mode
1 = LED1 is on end of the
001 = 20%
010 = 30%
011 = 40%
flash pulse
1 = Privacy
mode
(default)
mode turns off 100 = 50%
at the end of 101 = 60%
the flash pulse 110 = 70%
(default) 111 = 80%
33
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PRIVACY PWM PERIOD REGISTER
The Privacy PWM Register contains the bits to control the
PWM period for the privacy indicate mode (see Table 15).
TABLE 15. Privacy PWM Period Register
Bits 7-3
(Not Used)
Bit 2
(P3)
Bit 1
(P2)
Bit 0
(P1)
000 = 5.12 ms
001 = 2.56 ms
010 = 1.28 ms
011 = 640 µs
1XX = 320 µs
INDICATOR REGISTER
2. Pulse width
The Message Indicator Register contain the bits which control
the following:
3. Ramp times for turn-on and turn-off of the indicator
current source (see Figure 18 for the message indicator
timing diagram).
1. Indicator current level
TABLE 16. Indicator Register
Bit 4 (P2) Bit 3 (P1)
Bit 7 (R2)
(tRAMP
Bit 6 (R1)
Bit 5 (P3)
Bit 2 (I3)
(IIND
Bit 1 (I2)
Bit 0 (I1)
)
(PERIOD#)
000 = 0 (default)
001 = 1
)
00 = 78 ms (default)
01 = 156 ms
000 = 2.25 mA (default)
001 = 4.5 mA
010 = 2
011 = 3
10 = 312 ms
11 = 624 ms
010 = 6.75 mA
011 = 9 mA
100 = 4
101 = 5
110 = 6
111 = 7
100 = 11.25 mA
101 = 13.5 mA
110 = 15.75 mA
111 = 18 mA
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34
INDICATOR BLINKING REGISTER
2. Active Time (tACTIVE = tPERIOD × PERIOD# )
The Indicator Blinking Register contain the bits which control
the following:
3. Blank Time (tBLANK = tACTIVE × BLANK#)
(see Figure 18)
1. Number of periods (tPERIOD = tRAMP × 2 + tPULSE × 2)
TABLE 17. Indicator Blinking Register
Bit 7 (M4)
Bit 6 (M3)
Bit 5 (M2) Bit 4 (M1) Bit 3 (PW4) Bit 2 (PW3)
Bit 1 (PW2)
Bit 0 (PW1)
BLANK#
0000 = 0 (default)
0001 = 1
Pulse Time (tPULSE
0000 = 0 (default)
0001 = 32 ms
)
0010 = 2
0010 = 64 ms
0011 = 3
0011 = 92 ms
0100 = 4
0101 = 5
0110 = 6
0111 = 7
1000 = 8
1001 = 9
1010 = 10
1011 = 11
1100 = 12
1101 = 13
1110 = 14
1111 = 15
0100 = 128 ms
0101 = 160 ms
0110 = 196 ms
0111 = 224 ms
1000 = 256 ms
1001 = 288 ms
1010 = 320 ms
1011 = 352 ms
1100 = 384 ms
1101 = 416 ms
1110 = 448 ms
1111 = 480 ms
30102812
FIGURE 18. Message Indicator Timing Diagram
35
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Applications Information
OUTPUT CAPACITOR SELECTION
The LM3559 is designed to operate with at least a 10 µF ce-
ramic output capacitor. When the boost converter is running
the output capacitor supplies the load current during the boost
converters on-time. When the NMOS switch turns off the in-
ductor energy is discharged through the internal PMOS
switch, supplying power to the load and restoring charge to
the output capacitor. This causes a sag in the output voltage
during the on-time and a rise in the output voltage during the
off-time. The output capacitor is therefore chosen to limit the
output ripple to an acceptable level depending on load current
and input/output voltage differentials and also to ensure the
converter remains stable.
In ceramic capacitors the ESR is very low so a close approx-
imation is to assume that 80% of the output voltage ripple is
due to capacitor discharge and 20% from ESR. Table 18 lists
different manufacturers for various output capacitors and their
case sizes suitable for use with the LM3559.
INPUT CAPACITOR SELECTION
Choosing the correct size and type of input capacitor helps
minimize the voltage ripple caused by the switching of the
LM3559’s boost converter, and reduces noise on the boost
converter's input terminal that can feed through and disrupt
internal analog signals. In the Typical Application Circuit a 10
µF ceramic input capacitor works well. It is important to place
the input capacitor as close as possible to the LM3559’s input
(IN) terminal. This reduces the series resistance and induc-
tance that can inject noise into the device due to the input
switching currents. Table 18 lists various input capacitors that
or recommended for use with the LM3559.
For proper operation the output capacitor must be at least a
10 µF ceramic. Larger capacitors such as a 22 µF or capaci-
tors in parallel can be used if lower output voltage ripple is
desired. To estimate the output voltage ripple considering the
ripple due to capacitor discharge (ΔVQ) and the ripple due to
the capacitors ESR (ΔVESR) use the following equations:
For continuous conduction mode, the output voltage ripple
due to the capacitor discharge is:
The output voltage ripple due to the output capacitors ESR is
found by:
TABLE 18. Recommended Input/Output Capacitors (X5R Dielectric)
Manufacturer
TDK Corporation
TDK Corporation
TDK Corporation
Murata
Part Number
C1608JB0J106M
Value
10 µF
10 µF
22 µF
10 µF
10 µF
22 µF
Case Size
Voltage Rating
0603 (1.6mm×0.8mm×0.8mm)
0805 (2mm×1.25mm×1.25mm)
0805 (2mm×1.25mm×1.25mm)
0603 (1.6mmx0.8mmx0.8mm)
0805 (2mm×1.25mm×1.25mm)
0805 (2mm×1.25mm×1.25mm)
6.3V
10V
C2012JB1A106M
C2012JB0J226M
6.3V
6.3V
10V
GRM188R60J06M
GRM21BR61A106KE19
GRM21BR60J226ME39L
Murata
Murata
6.3V
INDUCTOR SELECTION
of the inductor and further efficiency loss. For proper inductor
operation and circuit performance ensure that the inductor
saturation and the peak current limit setting of the LM3559 is
greater than IPEAK in the following calculation:
The LM3559 is designed to use a 1 µH or 2.2 µH inductor.
Table 19 lists various inductors and their manufactures that
can work well with the LM3559. When the device is boosting
(VOUT > VIN) the inductor will typically be the largest area of
efficiency loss in the circuit. Therefore choosing an inductor
with the lowest possible series resistance is important. Addi-
tionally, the saturation rating of the inductor should be greater
than the maximum operating peak current of the LM3559.
This prevents excess efficiency loss that can occur with in-
ductors that operate in saturation and prevents over heating
ƒSW = 2MHz, and efficiency can be found in the Typical Per-
formance Characteristics plots.
TABLE 19. Recommended Inductors
ISAT
2.3A
3.4A
2.8A
2.3A
3.4A
RDC
Manufacturer
TOKO
L
Part Number Dimensions (L×W×H)
2.2 µH
1µH
FDSD0312-H-2R2M
FDSD0312-H-1R0M
FDSD0312-H-1R5M
FDSD0312-2R2M
FDSD0312-1R0M
3mm×3.2mm×1.2mm
3mm×3.2mm×1.2mm
3mm×3.2mm×1.2mm
3mm x 3mm x 1.2mm
3mm x 3mm x 1.2mm
105 mΩ
43 mΩ
71 mΩ
145 mΩ
70mΩ
TOKO
TOKO
1.5µH
2.2µH
1µH
TOKO
TOKO
www.national.com
36
ISAT
2.8A
1.5A
RDC
Manufacturer
TDK
L
Part Number
VLS4012ET-1R0N
VLS252012T-2R2M1R3
Dimensions (L×W×H)
4mm x 4mm x 1.2mm
2mm×2.5mm×1.2mm
1µH
50mΩ
TBD
TDK
2.2 µH
NTC THERMISTOR SELECTION
Programming bit [4] of Configuration Register 1 with a (1) se-
lects NTC mode and makes the LEDI/NTC pin a comparator
input for flash LED thermal sensing. Figure 19 shows the
LM3559 using the NTC thermistor circuit. The thermal sensor
resistor divider is composed of R3 and R(T), where R(T) is
the Negative Temperature Coefficient Thermistor, VBIAS is the
bias voltage for the resistive divider, and R3 is used to lin-
earize the NTC's response around the NTC comparators trip
point. CBYP is used to filter noise at the NTC input.
30102830
FIGURE 19. LM3559 Typical Application Circuit with Thermistor
In designing the NTC circuit, we must choose values for
VBIAS, R(T) and R3. To begin with, NTC thermistors have a
non-linear relationship between temperature and resistance:
where R(T)TRIP is the thermistors value at the temperature trip
point and VTRIP = 1V (typical). As an example, with VBIAS
=
2.5V and a thermistor whose nominal value at +25°C is 100
kΩ and a β = 4500K, the trip point is chosen to be +93°C. The
value of R(T) at 93°C is:
where β is given in the thermistor datasheet and R25C is the
thermistors value at +25°C. R3 is chosen so that the temper-
ature-to-resistance relationship becomes more linear and can
be found by solving for R3 in the R(T) and R3 resistive divider:
Figure 20 shows the linearity of the thermistor resistive divider
of the previous example.
37
www.national.com
30102834
FIGURE 20. Thermistor Resistive Divider Response vs Temperature
4. Avoid routing logic traces near the SW node so as to
Layout Recommendations
avoid any capacitively coupled voltages from SW onto
any high impedance logic lines such as TX1/TORCH/
GPIO1, TX2/INT/GPIO2, HWEN, LEDI/NTC (NTC
mode), SDA, and SCL. A good approach is to insert an
inner layer GND plane underneath the SW node and
between any nearby routed traces. This creates a shield
from the electric field generated at SW.
The high switching frequency and large switching currents of
the LM3559 make the choice of layout important. The follow-
ing steps should be used as a reference to ensure the device
is stable and maintains proper LED current regulation across
its intended operating voltage and current range.
1. Place CIN on the top layer (same layer as the LM3559)
and as close to the device as possible. The input
5. Terminate the Flash LED cathodes directly to the GND
pin of the LM3559. If possible, route the LED returns with
a dedicated path so as to keep the high amplitude LED
currents out of the GND plane. For Flash LEDs that are
routed relatively far away from the LM3559, a good
approach is to sandwich the forward and return current
paths over the top of each other on two layers. This will
help in reducing the inductance of the LED current paths.
capacitor conducts the driver currents during the low side
MOSFET turn-on and turn-off and can see current spikes
over 1A in amplitude. Connecting the input capacitor
through short wide traces to both the IN and GND
terminals will reduce the inductive voltage spikes that
occur during switching and which can corrupt the VIN line.
2. Place COUT on the top layer (same layer as the LM3559)
and as close as possible to the OUT and GND terminal.
The returns for both CIN and COUT should come together
at one point, and as close to the GND pin as possible.
Connecting COUT through short wide traces will reduce
the series inductance on the OUT and GND terminals
that can corrupt the VOUT and GND line and cause
excessive noise in the device and surrounding circuitry.
6. The NTC Thermistor is intended to have its return path
connected to the LEDs cathode. This allows the
thermistor resistive divider voltage (VNTC) to trip the
comparators threshold as VNTC is falling. Additionally, the
thermistor to LED cathode junction should be connected
as close as possible in order to reduce the thermal
impedance between the LED and the thermistor. The
draw back is that the thermistor's return will see the
switching currents from the LM3559's boost converter.
Because of this, it is necessary to have a filter capacitor
at the NTC pin which terminates close to the GND of the
LM3559 (see CBYP in ).
3. Connect the inductor on the top layer close to the SW pin.
There should be a low-impedance connection from the
inductor to SW due to the large DC inductor current, and
at the same time the area occupied by the SW node
should be small so as to reduce the capacitive coupling
of the high dV/dt present at SW that can couple into
nearby traces.
www.national.com
38
Physical Dimensions inches (millimeters) unless otherwise noted
TLA1611A: 16-Bump micro SMD
X1 = 1.97 mm (±0.03mm)
X2 = 1.97 mm (±0.03mm)
,X3 = 0.6 mm (±0.075 mm)
39
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