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Features
■
Buck-boost dc/dc converter
■
Drives one power white LED up to 800 mA from
2.7 V to 5.5 V in QFN
■
Drives one power white LED up to 800 mA from
3.3 V to 5.5 V in BGA
■
Efficient up to 92%
■
Output current control
■
1.8 MHz typ. fixed frequency PWM
■
Synchronous rectification
2
■
Full I
C control
■
Operational modes:
– Shutdown mode
– Shutdown + NTC
– Ready mode + auxiliary red LED
– Flash mode: up to 800 mA
– Torch mode: up to 200 mA
■
Soft and hard triggering of flash
■
Flash and torch dimming with 16 exponential
values
■
Dimmable red LED indicator auxiliary output
■
Internally or externally timed flash operation
■
Digitally programmable safety time-out in flash
mode
■
LED overtemperature detection and protection
with external NTC resistor
■
Opened and shorted led failure detection and
protection
■
Chip over temperature detection and protection
■
< 1 µA shutdown current
Table 1. Device summary
Order code
STCF03PNR
(1)
STCF03TBR
1. Available on request.
September 2007
High power white LED driver with I
Package
QFN20 (4x4 mm)
TFBGA25 (3x3 mm)
Rev. 4
QFN20 (4x4)
■
Packages:
– QFN20 (4x4)
– TFBGA25 (3x3)
Applications
■
Cell phone and smart phone
■
Camera flashes/strobe
■
PDAs and digital still cameras
Description
The STCF03 is a high efficiency power supply
solution to drive a single flash LED in camera
phone, PDAs and other hand-held devices. It is a
buck - boost converter to guarantee a proper LED
current control over all possible conditions of
battery voltage and output voltage; the output
current control ensure a good current regulation
over the forward voltage spread characteristics of
the Flash LED.
Thanks to the high efficiency of the converter
allows having the input current taken from the
battery remain under 1.5 A. (See continuous
description)
4500 parts per reel
3000 parts per reel
STCF03
2
C™ interface
TFBGA25 (3x3)
Packaging
1/35
www.st.com
35
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Related Manuals for STMicroelectronics STCF03
Summary of Contents for STMicroelectronics STCF03
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Page 1: Table 1. Device Summary
Description ■ Flash and torch dimming with 16 exponential values The STCF03 is a high efficiency power supply solution to drive a single flash LED in camera ■ Dimmable red LED indicator auxiliary output phone, PDAs and other hand-held devices. It is a ■... -
Page 2: Table Of Contents
STCF03 Contents Description (continued) ........6 Diagram . - Page 3 STCF03 TCH_ON ..........20 NTC_ON .
- Page 4 List of figures STCF03 List of figures Figure 1. Block diagram ............7 Figure 2.
- Page 5 List of tables STCF03 List of tables Table 1. Device summary ............1 Table 2.
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Page 6: Description (Continued)
Description (continued) STCF03 Description (continued) All the functions of the device are controlled through the I C which helps bus that allows to reduce logic pins on the package and to save PCB tracks on the board. Hard and soft- triggering of Flash are both supported. -
Page 7: Diagram
Diagram STCF03 Diagram Figure 1. Block diagram 7/35... -
Page 8: Pin Configuration
Pin configuration STCF03 Pin configuration Figure 2. Pin connections (bottom view) QFN20 (3x3) TFBGA25 (3x3) Table 2. Pin description Pin n° for Pin n° for Symbol Name and function QFN20 TFBGA25 E1, D2 VLX2 Inductor connection Rx resistor connection NTC resistor connection... -
Page 9: Maximum Ratings
Maximum ratings STCF03 Maximum ratings Table 3. Absolute maximum ratings (see note) Symbol Parameter Value Unit VBAT Signal supply voltage -0.3 to 6 PVBAT Power supply voltage -0.3 to 6 VLX1A, VLX1B Inductor connection 1 –0.3 to V +0.3 VLX2 Inductor connection 2 –0.3 to V... -
Page 10: Application
3.7 x 3.5 x 1.2mm FLASH Murata NCP21WF104J03RA 100kΩ 0805 0.27Ω 0603 1.8Ω 0402 15kΩ 0402 Note: All of the above listed components refer to typical application. Operation of the STCF03 is not limited to the choice of these external components. 10/35... -
Page 11: Electrical Characteristics
Electrical characteristics STCF03 Electrical characteristics Table 6. Electrical characteristics = 0.27 Ω R = 1.8 Ω, R = 25°C, V = 3.6 V, 2xC = 10 µF, C = 1 µF, L = 4.7 µH, R = 15 KΩ, Typ. values @25°C, unless otherwise specified). -
Page 12: Table 6. Electrical Characteristics
Electrical characteristics STCF03 Table 6. Electrical characteristics = 0.27 Ω R = 1.8 Ω, R = 25°C, V = 3.6 V, 2xC = 10 µF, C = 1 µF, L = 4.7 µH, R = 15 KΩ, Typ. values @25°C, unless otherwise specified). -
Page 13: Introduction
ATN pin This output pin (open-drain, active LOW) is provided to better manage the information transfer from the STCF03 to the µP. Because of the limitations of a Single Master I C bus configuration, the µP should regularly poll the STCF03 to verify if certain operations have been completed, or to check diagnostic information. -
Page 14: Add Pin
C BUS interface Data transmission from the main µP STCF03 and vice versa takes place through the 2 wires C bus interface wires, consisting of the two lines SDA and SCL (pull-up resistors to a positive supply voltage must be externally connected). The recommended maximum voltage of these signals should be 3.0 V. -
Page 15: Start And Stop Conditions
Introduction STCF03 Start and stop conditions Both DATA and CLOCK lines remain HIGH when the bus is not busy. As shown in Figure 5 start condition is a HIGH to LOW transition of the SDA line while SCL is HIGH. The stop condition is a LOW to HIGH transition of the SDA line while SCL is HIGH. -
Page 16: Acknowledge
Then the master waits for an acknowledge from STCF03. Then the 8 bit address of register is sent to STCF03. It is also followed by an acknowledge pulse. The last transmitted byte is the data that is going to be written to the register. It is again followed by an acknowledge pulse from STCF03. -
Page 17: Interface Protocol
It would be unpractical to send several times the device address and the address of the register when writing to multiple registers. STCF03 supports writing to multiple registers with incremental addressing. When the data is written to a register, the address register is automatically increased, so the next data can be sent without sending the device address and the register address again. -
Page 18: Reading From A Single Register
Then the master generates a START bit again and sends the device address followed by the R/W bit, which is 1 now. STCF03 confirms the receiving of the address + R/W bit by an acknowledge pulse and starts to send the data to the master. No acknowledge pulse from the master is required after receiving the data. -
Page 19: Figure 11. Reading From Multiple Registers
Introduction STCF03 the register address again. The last acknowledge pulse before the STOP bit is not required. See the Figure Figure 11. Reading from multiple registers DEVICE DEVICE DEVICE DEVICE ADDRESS ADDRESS ADDRESS OF ADDRESS OF ADDRESS ADDRESS REGISTER i... -
Page 20: Description Of Internal Registers
PWR_ON=1. LED current is controlled by the value set by the FDIM_0~3 of the DIM_REG. TCH_ON When set from Ready Mode, the STCF03 enters the Torch mode. The LED current is controlled by the value set by the TDIM_0~3 of the DIM_REG. NTC_ON In ready mode, the comparators that monitor the LED temperature are activated if NTC_ON bit is set. -
Page 21: Ftim_0~3
This 4bit register defines the maximum Flash duration. It is intended to limit the energy dissipated by the LED to a maximum safe value or to leave to the STCF03 the control of the Flash duration during normal operation. Values from 0~15 correspond to 0~1.5s (100ms steps). -
Page 22: Auxi_0~3
Description of internal registers STCF03 Table 12. Auxiliary register AUX_REG (write mode) SUB ADD=02 AUXI_3 AUXI_2 AUXI_1 AUXI_0 AUXT_3 AUXT_2 AUXT_1 AUXT_0 Power ON, SHUTDOWN MODE RESET Value AUXI_0~3 This 4 bits register defines the AUX LED current from 0 to 20 mA. See AUX LED Dimming Table for reference. -
Page 23: F_Run
STAT_REG. 8.12 NTC_W This bit is set HIGH by the STCF03 and the ATN pin is pulled down, when the voltage seen on the pin Rx exceeds V = 0.56 V. This threshold corresponds to a warning temperature REF4 value at the LED measured by the NTC. -
Page 24: Voutok_N
8.15 VOUTOK_N This bit is set by the STCF03. It is used to protect the device, if the output is shorted. The VOUTOK_N bit is set to HIGH at the start-up. Then a current generator of 20mA charges the output capacitor for 360 µs typ. and it detects when the output capacitor reaches 100 mV. If this threshold is reached the bit is set to LOW. -
Page 25: Detailed Description
A/D converter. When NTC circuits are active and the V is present, the typ. current REF-EXT consumption is increased to 1 µA, then it is recommended not to leave the STCF03 in this status if battery drain has to be minimized. Ready mode In this mode all internal blocks are turned ON, but the DC/DC converter is disabled and the White LED is disconnected. -
Page 26: External (Μp) Temporization Using Trig_En Bit
I C bus time latency. Stop time is defined by the STCF03 internal temporization and its accuracy is determined by the internal oscillator. For hard-triggering it is necessary to set the TRIG_EN bit in advance. For soft-triggering the... -
Page 27: Typical Performance Characteristics
Typical performance characteristics STCF03 Typical performance characteristics Figure 14. Efficiency Figure 15. I vs T_DIMM OTORCH Efficiency of the application at Io=800mA Efficiency of the application at Io=800mA Efficiency of the application at Io=55mA Efficiency of the application at Io=55mA = 2.7V... -
Page 28: Figure 20. I Q Vs Temp
Typical performance characteristics STCF03 Figure 20. I vs Temp. V = 5.5V Ready-Mode Figure 21. Start-Up in Flash Mode 800mA at = 3.6V TRIG I_IN -40°C -40°C 25°C 25°C 85°C 85°C Temp. Temp. Figure 22. Line transient in Flash Mode 800mA, change of V from 2.7V to... -
Page 29: Package Mechanical Data
Package mechanical data STCF03 Package mechanical data In order to meet environmental requirements, ST offers these devices in ECOPACK® packages. These packages have a Lead-free second level interconnect. The category of second level interconnect is marked on the package and on the inner box label, in compliance with JEDEC Standard JESD97. - Page 30 Package mechanical data STCF03 QFN20 (4mm x 4mm) mechanical data mils. Dim. Min. Typ. Max. Min. Typ. Max. 0.80 0.90 1.00 31.5 35.4 39.4 0.02 0.05 0.65 1.00 25.6 39.4 0.20 0.18 0.25 0.30 11.8 3.85 4.00 4.15 151.6 157.5 163.4...
- Page 31 Package mechanical data STCF03 TFBGA25 mechanical data mils. Dim. Min. Typ. Max. Min. Typ. Max. 1.16 39.4 43.3 45.7 0.25 0.78 0.86 30.7 33.9 0.25 0.30 0.35 11.8 13.8 114.2 118.1 122.0 78.8 114.2 118.1 122.0 78.8 19.7 0.25 7539979/A...
- Page 32 Package mechanical data STCF03 Tape & reel QFNxx/DFNxx (4x4) mechanical data inch. Dim. Min. Typ. Max. Min. Typ. Max. 12.992 12.8 13.2 0.504 0.519 20.2 0.795 3.898 3.976 14.4 0.567 4.35 0.171 4.35 0.171 0.043 0.157 0.315 32/35...
- Page 33 Package mechanical data STCF03 Tape & reel TFBGA25 mechanical data inch. Dim. Min. Typ. Max. Min. Typ. Max. 12.992 12.8 13.2 0.504 0.519 20.2 0.795 2.362 14.4 0.567 0.130 0.130 1.60 0.063 0.153 0.161 0.311 0.319 33/35...
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Page 34: Revision History
Revision history STCF03 Revision history Table 17. Document revision history Date Revision Changes 30-Jan-2007 First Release. 27-Mar-2007 The OVP min. value on table 5 is changed: 5.5 V ==> 5.3 V. 28-Aug-2007 Table 5. updated. 12-Sep-2007 Figure 2. title changed. - Page 35 Please Read Carefully: Information in this document is provided solely in connection with ST products. STMicroelectronics NV and its subsidiaries (“ST”) reserve the right to make changes, corrections, modifications or improvements, to this document, and the products and services described herein at any time, without notice.
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