STCF05 STMicroelectronics, STCF05 Datasheet

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STCF05

Manufacturer Part Number
STCF05
Description
HIGH POWER WHITE LED DRIVER WITH I2C INTERFACE
Manufacturer
STMicroelectronics
Datasheet

Specifications of STCF05

Flash Mode
up to 400 mA
Torch Mode
up to 120 mA
Features
Table 1.
July 2010
Boost DC-DC converter with synchronous
rectification
Drives 2 power white LEDs in series with a
current up to 400 mA
Input voltage range 2.5 V to 5.5 V
Needs 3 external components only
Output current control
1.8 MHz fixed frequency PWM control
Peak inductor current limited to 3 A
Full I²C control
Operational modes:
– Standby mode
– Standby mode with NTC
– Flash mode: up to 400 mA
– Torch mode: up to 120 mA
Soft and hard triggering of flash
Flash and Torch dimming in 15 exponential
steps
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
Open and shorted LED failure detection and
protection
Chip overtemperature detection and protection
Less than 1 µA standby current
Package 3 x 3 mm TFBGA25
STCF05TBR
Order code
Device summary
High power white LED driver with I²C interface
TFBGA25 (3 x 3 mm)
Doc ID 15257 Rev 4
Package
Applications
Description
The STCF05 is a high efficiency power supply
solution to drive multiple flash LEDs in camera
phones, PDAs and other hand-held devices. The
synchronous boost topology with output current
control guarantees the proper LED current over
all possible conditions of battery level and LED
forward voltage. All the functions of the device are
controlled through the I²C bus that allows to
reduce logic pins on the package and to save
PCB traces on the board. Hard and soft-triggering
of the flash are both supported. The device
includes many functions to protect the chip and
the power LEDs. These comprehend a soft-start
control, chip over temperature detection and
protection, open and shorted LEDs detection and
protection. In addition, a digital programmable
time-out function protects the LEDs in case of
wrong command from microprocessor. See
description (continued).
Cell phones and smartphones
Camera flashes/strobe
PDAs and digital still cameras
TFBGA25 (3 x 3 mm)
3000 parts per reel
Packaging
STCF05
www.st.com
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Related parts for STCF05

STCF05 Summary of contents

Page 1

... Camera flashes/strobe ■ PDAs and digital still cameras Description The STCF05 is a high efficiency power supply solution to drive multiple flash LEDs in camera phones, PDAs and other hand-held devices. The synchronous boost topology with output current control guarantees the proper LED current over all possible conditions of battery level and LED forward voltage ...

Page 2

... Interface protocol . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 8.6 Writing to a single register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 8.7 Writing to multiple registers with incremental addressing . . . . . . . . . . . . 17 8.8 Reading from a single register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 8.9 Reading from multiple registers with incremental addressing . . . . . . . . . 18 9 Registers description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 2/33 SCL, SDA pins . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 TRIG pin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 ATN pin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 ADD pin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 TMSK pin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 Doc ID 15257 Rev 4 STCF05 ...

Page 3

... STCF05 9.1 PWR_ON . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 9.2 TRIG_EN . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 9.3 TCH_ON . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 9.4 NTC_ON . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 9.5 FTIM_0 9.6 TDIM_0 9.7 FDIM_0 9.8 LDIM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 9.9 AUXI_0 9.10 AUXT_0 9.11 LED_S . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 9.12 F_RUN . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 9.13 LED_O . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 9.14 NTC_W . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 9.15 NTC_H . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 9.16 OT_F . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 9.17 OC_F . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 9.18 VOUTOK_N . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 10 Detailed description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 10.1 Power ON reset . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 10.2 Shutdown, shutdown with NTC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 10.3 Ready mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 10.4 Single or multiple flash using external (microprocessor) temporization . . 25 10.5 External (microprocessor) temporization using TRIG_EN bit . . . . . . . . . 26 10 ...

Page 4

... I²C register mapping read function . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 Table 10. Command register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 Table 11. Dimming register Table 12. Auxiliary register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 Table 13. Auxiliary LED dimming table . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 Table 14. Torch mode and flash mode dimming registers settings . . . . . . . . . . . . . . . . . . . . . . . . . . 23 Table 15. Status register Table 16. Status register details . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 Table 17. Document revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32 4/33 Doc ID 15257 Rev 4 STCF05 ...

Page 5

... STCF05 List of figures Figure 1. Block diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 Figure 2. Pin connections (top view Figure 3. Application schematic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 Figure 4. Data validity on the I²C bus Figure 5. Timing diagram on I²C bus . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 Figure 6. Bit transfer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 Figure 7. Acknowledge on I²C bus . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 Figure 8. Writing to a single register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 Figure 9. Writing to multiple register with incremental addressing Figure 10 ...

Page 6

... It is possible to separately program the current intensity in flash and torch mode using exponential steps by I²C. In case of insufficient power from the battery a warning is generated. An auxiliary output can control an optional red LED to be used as a recording indicator. The device is packaged in BGA with 1 mm height. 6/33 Doc ID 15257 Rev 4 STCF05 ...

Page 7

... STCF05 2 Diagram Figure 1. Block diagram Doc ID 15257 Rev 4 Diagram 7/33 ...

Page 8

... Signal ground ADD I²C address selection LED Diode cathode connection ATN Attention (open drain output, active LOW) VBAT Supply voltage SDA I²C data TMSK T-mask PGND Power ground + die back connection Doc ID 15257 Rev TRIG TMSK AUXL NTC RX Description STCF05 ...

Page 9

... STCF05 4 Maximum ratings Table 3. Absolute maximum ratings Symbol VBAT Signal supply voltage VLX Inductor connection OUT Output voltage AUXL Auxiliary LED LED LEDs connection SCL, SDA, TRIG, Logic pin ATN, ADD TMSK R Connection for reference resistor X NTC Connection for LED temperature sensing ...

Page 10

... Inductor type is recommended for high efficiency operation 85 % typ. at 400 mA output current. 2. This inductor type is recommended for the minimum app. area with typ. efficiency of the operation 400 mA output current Note: Above listed components refer to typical application. Operation of the STCF05 is not limited to the choice of these external components. 10/33 = 1.8 V. ...

Page 11

... STCF05 6 Electrical characteristics ° 3 °C, unless otherwise specified. Table 6. Electrical characteristics Symbol Parameter Input operating supply V IN voltage V Power ON reset PW_ON threshold RESET Output current adjustment range I FLASH Output current adjustment range TORCH Auxiliary LED output ...

Page 12

... LED current rise time =max LED LED 1. Typical value, not production test. 2. Calculated )/(V *I OUT LED Calculated )/(V *I LED LED IN IN 12/33 Test conditions V =3.3V ATN V =2. Doc ID 15257 Rev 4 STCF05 Min. Typ. Max. Unit 0 ...

Page 13

... Boost converter The STCF05 contains the 3-loop system of the PWM controller regulation and soft-start function. When the output voltage is lower than input voltage, the STCF05 is charging output by the internal current source with 120 mA typ. When the output voltage is higher than battery, the STCF05 automatically enable the boost converter with 3-loop regulation system. ...

Page 14

... LED is forced at 100 mA typ. Neither internal pull-up nor pull-down is provided. This pin must be externally wired to GND if TX masking function is not used. 14/ Doc ID 15257 Rev 4 STCF05 Table ...

Page 15

... STCF05 8 I²C bus interface Data transmission from the main microprocessor to STCF05 and vice versa takes place through the 2 I²C bus interface wires, consisting of the two lines SDA and SCL (pull-up resistors to a positive supply voltage must be externally connected). 8.1 Data validity ...

Page 16

... SDA line remains at the HIGH level during the ninth clock pulse duration. In this case, the master transmitter can generate the STOP information in order to abort the transfer. The STCF05 won't generate the acknowledge if the V ...

Page 17

... STCF05. The 8 operation. Then the master waits for an acknowledge from STCF05. Then the 8 bit address of register is sent to STCF05 also followed by an acknowledge pulse. The last transmitted byte is the data that is going to be written to the register again followed by an acknowledge pulse from STCF05. The master then generates a STOP bit and the communication is over ...

Page 18

... R/W bit by an acknowledge pulse. The address of the register which should be read is sent afterwards and confirmed again by an acknowledge pulse of STCF05 again. Then the master generates a START bit again and sends the device address followed by the R/W bit, which is 1 now. STCF05 confirms the receiving of the address + R/W bit by an 18/33 W ...

Page 19

... STCF05 acknowledge pulse and starts to send the data to the master. No acknowledge pulse from the master is required after receiving the data. Then the master generates a STOP bit to terminate the communication. See Figure 10. Reading from a single register DEVICE DEVICE ADDRESS ADDRESS 7 bits 7 bits ...

Page 20

... SUB ADD=01 N/A Power ON, SHUTDOWN 0 RESET Value MODE 20/33 SUB ADDRESS (hex TRIG_EN TCH_ON NTC_ON TDIM_2 TDIM_1 TDIM_0 Doc ID 15257 Rev 4 Operation only FTIM_3 FTIM_2 FTIM_1 N/A FDIM_2 FDIM_1 STCF05 LSB FTIM_0 0 LSB FDIM_0 0 ...

Page 21

... FTIM_0~3 This 4-bits register defines the maximum flash duration intended to limit the energy dissipated by the LED to a maximum safe value or to leave to the STCF05 the control of the flash duration during normal operation. Values from 0~15 correspond to 0~1.5 s (100 ms steps). The timing accuracy is related to the internal oscillator frequency that clocks the flash time counter ...

Page 22

... The AUX LED current source is active only in ready mode, and is deactivated in any other mode. 22/ dimming steps dimming steps AUXI_2 AUXI_1 AUXI_0 Doc ID 15257 Rev 4 Table 14 below AUXT_3 AUXT_2 AUXT_1 STCF05 LSB AUXT_0 0 ...

Page 23

... SHUTDOWN MODE 0 RESET Value 9.11 LED_S This bit is set by the STCF05 when the voltage seen on the current mirror is above 1.2 V during a torch or flash operation. This condition can be caused by shorted LEDs, This bit is reset by the STCF05 following a read operation of the STAT_REG. 9.12 F_RUN This bit is kept HIGH by the STCF05 during flash mode. By checking this bit, the microprocessor can verify if the flash mode is running or has been terminated by the time counter ...

Page 24

... VOUTOK_N This bit is set by the STCF05 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 charges the output capacitor for 360 µs typ. and it detects when the output capacitor reaches 100 mV ...

Page 25

... STCF05 Figure 13. VOUTOK_N behavior Table 16. Status register details F_RUN Bit name LED_S (STAT_ REG) Default 0 0 value Latched YES NO (1) Forces Ready NO NO mode when set Sets ATN LOW YES NO when set 1. YES means that the bit is set by internal signals and is reset to default by an I²C read operation of STAT_REG. NO means that the bit is set and reset by internal signals in real-time ...

Page 26

... The registers are reset to their default values, the ATN and SDA pins are in high impedance, the I²C slave address is internally set by reading the ADD pin configuration. After the internally defined time has elapsed, the STCF05 automatically enters the shutdown mode. 10.2 Shutdown, shutdown with NTC In this mode only the I² ...

Page 27

... The first solution is recommended for an accurate start time, while the second is less accurate because of the I²C bus time latency. Stop time is defined by the STCF05 internal temporization and its accuracy is determined by the internal oscillator. For hard-triggering necessary to set the TRIG_EN bit in advance. For soft-triggering, the TRIG pin has to be kept High (logic level or wired to VBAT) and the flash can be started by setting the FTIM and the TRIG_EN through I² ...

Page 28

... BAT BAT vs. V LED OUT VB A T=3.6V V BAT VOUT [V] V [V] OUT Ready Mode Ready Mode Ready Mode + Ready Mode + Aux LED Aux LED -40 -40 -20 - [°C] T [°C] STCF05 5 5 5.5 5 100 100 ...

Page 29

... STCF05 12 Package mechanical data In order to meet environmental requirements, ST offers these devices in different grades of ® ECOPACK packages, depending on their level of environmental compliance. ECOPACK specifications, grade definitions and product status are available at trademark. Doc ID 15257 Rev 4 Package mechanical data ® www.st.com. ...

Page 30

... Package mechanical data Dim. Min 0.78 b 0. 30/33 TFBGA25 mechanical data mm. Typ. Max. 1.1 1.16 0.25 0.86 0.30 0.35 3.0 3.1 2 3.0 3.1 2 0.5 0.25 Doc ID 15257 Rev 4 mils. Min. Typ. 39.4 43.3 30.7 9.8 11.8 114.2 118.1 78.8 114.2 118.1 78.8 19.7 9.8 7539979/A STCF05 Max. 45.7 9.8 33.9 13.8 122.0 122.0 ...

Page 31

... STCF05 Tape & reel TFBGA25 mechanical data Dim. Min 12 3.9 P 7.9 mm. Typ. Max. Min. 330 13.2 0.504 0.795 2.362 14.4 3.3 3.3 1.60 4.1 0.153 8.1 0.311 Doc ID 15257 Rev 4 Package mechanical data inch. Typ. Max. 12.992 0.519 0.567 0.130 0.130 0.063 0.161 0.319 ...

Page 32

... Revision history 13 Revision history Table 17. Document revision history Date Revision 09-Dec-2008 1 30-Mar-2009 2 26-Apr-2010 3 28-Jul-2010 4 32/33 Initial release. Modified Figure 17 and Figure 19 on page Modified Figure 18 on page 28. Modified Table 3 on page 9. Doc ID 15257 Rev 4 Changes 28. STCF05 ...

Page 33

... STCF05 Information in this document is provided solely in connection with ST products. STMicroelectronics NV and its subsidiaries (“ST”) reserve the right to make changes, corrections, modifications or improvements, to this document, and the products and services described herein at any time, without notice. All ST products are sold pursuant to ST’s terms and conditions of sale. ...

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