STCF07 STMicroelectronics, STCF07 Datasheet
STCF07
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STCF07 Summary of contents
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... April 2011 High power buck-boost white LED driver QFN16 ( mm) Description The STCF07 is a dedicated, size-optimized solution for driving a power LED. The device is a buck-boost converter which guarantees proper LED current control over all possible battery voltage and LED forward voltage conditions. The ...
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... FAULT pin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 7.3 ENABLE pin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 8 Detailed description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 8.1 Buck-boost converter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 8.2 High current mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 8.3 Low current mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 8.4 Shutdown mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 8.5 Soft-start . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 8.6 STCF07 protection features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 8.6.1 8.6.2 8.6.3 8.6.4 8.6.5 9 PCB design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 9.1 PCB design rules . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 9.2 PCB design of the demonstration board . . . . . . . . . . . . . . . . . . . . . . . . . 16 9.3 Schematic of the demonstration board . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 2/26 Peak current and short-circuit protection . . . . . . . . . . . . . . . . . . . . . . . . 13 Overvoltage protection ...
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... STCF07 10 Typical performance characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 11 External component selection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 11.1 Input and output capacitor selection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 11.2 Inductor selection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 11.3 LED selection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 11.4 RHC selection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 11.5 RLC selection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 11.6 NTC and RX resistor selection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 12 Package mechanical data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 13 Revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 Doc ID 16757 Rev 2 Contents 3/26 ...
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... Block diagram 1 Block diagram Figure 1. STCF07 block diagram VLX1B VLX1B PVBAT PVBAT VBAT VBAT GND GND ENABLE ENABLE CSEL CSEL FAULT FAULT BANDGAP BANDGAP REF REF 4/26 VLX1A VLX1A CURRENT CURRENT PROTECTION PROTECTION LOGIC LOGIC OVER OVER TEMP TEMP SOFT SOFT START ...
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... STCF07 2 Pin configuration Figure 2. STCF07 pin connections (top view) Table 2. STCF07 pin description Pin n° Symbol 1 VLX2 NTC 3 VOUT 4 FB1 5 FB2 6 FB2S 14 GND 13 CSEL FAULT 9 PVBAT 10 VBAT 11 VLX1A 12 VLX1B 15 PGND Exposed pad PGND Description Inductor VLX2 connection R resistor connection ...
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... Table 4. Thermal data Symbol (1) R Thermal resistance junction-ambient thJA 1. Junction-to-ambient thermal resistance in JEDEC still air chamber. Thermal test board JESD51-7 (leaded surface mount packages). 6/26 Parameter = 70 °C) A Parameter Doc ID 16757 Rev 2 STCF07 Value Unit - ...
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... Tyco Electronics X LED Luxeon 1. For 800 mA output current performance. 2. For 1000 mA output current performance. Note: The above-listed external components refer to a typical application. Operation of the STCF07 is not limited to the use of these components VLX1 VLX1 VLX1 VLX1 VLX2 VLX2 VOUT VOUT ...
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... V, no load 5 load Max NTC Shutdown mode GND NTC 2 5 Doc ID 16757 Rev 2 STCF07 = 0.22 Ω 1.8 Ω Min. Typ. Max. Unit 2.7 5.5 V 2.2 V 2.3 V 1000 1000 mA 20 2.5 5.3 V 2.3 A 152 160 ...
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... STCF07 Table 6. Electrical characteristics (continued) Symbol Parameter Low level voltage FAULT Leakage current LED current rise time max LED LED Test conditions SINK FAULT Doc ID 16757 Rev 2 Electrical characteristics Min. Typ. Max. Unit 0.2 0 µ ...
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... Introduction 6 Introduction The STCF07 is a buck-boost converter designed to power and control the current of a power white LED. The device operates at a constant switching frequency of 1.8 MHz (typ). It provides an output voltage from 2 5.3 V, from a 2 5.5 V supply voltage. This supply range allows the device to operate from a single-cell Lithium-Ion battery. The current is adjustable for an input voltage ranging from 2 ...
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... FB1 and FB2 pins. The feedback voltage is sensed directly on the sensing R current operation. 7.2 FAULT pin When the STCF07 mode (EN is high), the device is able to detect disconnection or failure of the LED. This information can be used by the system to signal that a problem has occurred in the LEDs. 7.3 ENABLE pin This pin functions as an enable input ...
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... High current mode ENABLE = CSEL = V The STCF07 operates continuously to supply maximum current to the LED up to 800 mA in high current mode. If high current mode is used in flash applications, then it is possible to increase the LED current up to 1066 mA. The current can be adjusted with the R ...
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... OUT OUT I I LED LED 8.6 STCF07 protection features 8.6.1 Peak current and short-circuit protection When the peak inductor current exceeds the maximum switch peak current limit of 2.3 A, the PWM controller turns off and is enabled at the next oscillation period. 8.6.2 Overvoltage protection The device includes power failure protection, which stops the operation of the PWM ...
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... If the device is ON and the battery voltage is as low as 2.2 V, the device goes into a FAULT state and the FAULT pin is put to LOW. To restart the device, the ENABLE pin must be reset LOW and HIGH. 14/ 100 k = 100 k NTC NTC NTC NTC Vref = 1.8 V Vref = 1 1 1.2 V REF REF Doc ID 16757 Rev STCF07 ...
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... PCB design rules The STCF07 is a powerful switched device, so the PCB must be designed following the rules for designing switched supplies recommended to use at least a two-layer PCB. The power wiring must be as short and wide as possible, due to the high current. All external components should be placed close to the STCF07 ...
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... PCB design 9.2 PCB design of the demonstration board Figure 6. Top layer Figure 7. Bottom layer 16/26 Doc ID 16757 Rev 2 STCF07 ...
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... STCF07 Figure 8. Top overlay Doc ID 16757 Rev 2 PCB design 17/26 ...
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... PCB design 9.3 Schematic of the demonstration board Figure 9. Schematic diagram of the STCF07 demonstration board 18/26 Doc ID 16757 Rev 2 STCF07 ...
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... STCF07 Typical performance characteristics 10 Figure 10 vs. V OUT 100.000 100.000 95.000 95.000 90.000 90.000 85.000 85.000 80.000 80.000 75.000 75.000 70.000 70.000 25 °C 25 °C 65.000 65.000 - 40 ° °C 60.000 60.000 85°C 85°C 55.000 55.000 50.000 50.000 2.50 2.50 3.00 3.00 3.50 3.50 4.00 4.00 Input Voltage [V] Input Voltage [V] Figure 12 ...
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... LED selection All LEDs with forward voltages from 2 are suitable for use with STCF07 device. The LED forward voltage must include the voltage spread of this value possible to set the LED current in the two different operating modes (high current mode and low current mode) through two external sensing resistors ...
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... STCF07 11.5 R selection LC R resistor value can be calculated with the following equations (160 where P is the dissipated power on the R RLC metal film resistor with tolerance. 11.6 NTC and R X The NTC resistor for sensing LED temperature and the R The output of this divider is compared with the 1.192 V internal voltage reference. When voltage on the output of the voltage divider is increased over the reference, the logic switches off the power circuit ...
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... Package mechanical data 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: www.st.com. ® ECOPACK trademark. 22/26 Doc ID 16757 Rev 2 STCF07 ® ...
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... STCF07 Dim. Min 0.18 D 3.85 D2 2.10 E 3. 0.30 ddd QFN16 ( mechanical data mm. Typ. Max. 0.90 1.00 0.02 0.05 0.65 1.00 0.20 0.25 0.30 4.00 4.15 2.60 4.00 4.15 2.60 0.50 0.40 0.50 0.08 Doc ID 16757 Rev 2 Package mechanical data inch. Min. Typ. 31.5 35.4 0.8 25.6 7.9 7.1 9.8 151.6 157.5 163.4 82.7 102.4 151.6 157.5 163.4 82.7 102.4 19.7 11.8 15.7 7653321A Max. 39.4 2.0 39.4 11.8 19.7 3.1 23/26 ...
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... Package mechanical data Tape & reel QFNxx/DFNxx (4x4) mechanical data Dim. Min 12 24/26 mm. Typ. Max. Min. 330 13.2 0.504 0.795 101 3.898 14.4 4.35 4.35 1 Doc ID 16757 Rev 2 STCF07 inch. Typ. Max. 12.992 0.519 3.976 0.567 0.171 0.171 0.043 0.157 0.315 ...
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... STCF07 13 Revision history Table 7. Document revision history Date Revision 18-Nov-2009 1 12-Apr-2011 2 First release. Updated Table 5 on page 7. Doc ID 16757 Rev 2 Revision history Changes 25/26 ...
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... Australia - Belgium - Brazil - Canada - China - Czech Republic - Finland - France - Germany - Hong Kong - India - Israel - Italy - Japan - Malaysia - Malta - Morocco - Philippines - Singapore - Spain - Sweden - Switzerland - United Kingdom - United States of America 26/26 Please Read Carefully: © 2011 STMicroelectronics - All rights reserved STMicroelectronics group of companies www.st.com Doc ID 16757 Rev 2 STCF07 ...