STLDC08 STMicroelectronics, STLDC08 Datasheet
STLDC08
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STLDC08 Summary of contents
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... MOSFET (N-channel) enabling it for use with wide power levels. Hysteretic control eliminates the need for small signal control loop compensation. The IC integrates an FET driver for a precise PWM dimming. STLDC08 comes in a DFN10 ( mm) package. Table 1. Device summary Order code ...
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... Over voltage protection (OVP 7.4 Enable/PWM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 7.5 Dimming . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 8 Application information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 8.1 LED current programming . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 8.2 Duty cycle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 8.3 Inductor selection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 8.4 Inductor peak current limit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 8.5 Power MOSFET selection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 8.6 Schottky diode selection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 8.7 Input capacitor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 8.8 Output capacitor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 9 Demonstration board . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 10 Layout suggestion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 11 Package mechanical data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24 2/29 Doc ID 18476 Rev 1 STLDC08 ...
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... STLDC08 12 Revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 Doc ID 18476 Rev 1 Contents 3/29 ...
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... Part number GRM21BR60J475 GRM31CB31C106K GRM188R70J103KA01B GRM188R61C105K LPS6235-103ML STS5DNF20V STPS2L30 Doc ID 18476 Rev 1 = 200 mA LED Value Size 4.7 µF, 6.3 V 0805 10 µ 1206 10 nF, 6.3 V 0603 1 µ 0603 10 µ SO-8 SMA 0.47 Ω 0805 0.047 Ω 0805 0 Ω 0603 STLDC08 Rfb ...
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... STLDC08 Figure 2. Electric schematic optimized for 4 LEDs and I RF BATTERY VCC 7 EN/PWM EN/PWM 3 2VCC Table 3. List of components Part reference Manufacturer C1 Murata C2 Murata C4 Murata C3, C5, C6 Murata M1,M2 STMicroelectronics D1 STMicroelectronics L Coilcraft Rfb Rs RF LED DRV 6 SENSE 1 VOUT 2 PWMOUT 5 FB GND ...
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... Table 5. Thermal data Symbol R Thermal resistance junction-case thJC R Thermal resistance junction-ambient thJA 1. With two sides, two planes PCB following EIA/JEDEC JESD51-7 standard. 6/29 Parameter = 25 °C A Parameter Doc ID 18476 Rev 1 STLDC08 Value Unit - 0 ...
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... STLDC08 3 Pin configuration Figure 3. Pin connections (top through view) Bottom view Table 6. Pin description Pin # Pin name 1 VOUT Over voltage protection and supply pin for the IC when V Driver of the external MOSFET for PWM dimming. The driver stage is controlled by 2 PWMOUT EN/PWM signal ...
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... PWMOUT C = 3300 pF PWMOUT C = 3300 pF PWMOUT Doc ID 18476 Rev 1 Min. Typ. Max. 0 800 1 0.8 V 1.5 80 120 105 200 250 30 20 STLDC08 = unless CC Unit 3 µA 19.5 V 100 µA µ µA V 160 mV 240 116 mV 500 nA µs µs 400 ...
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... STLDC08 Table 7. Electrical characteristics (continued) Symbol Parameter SENSE Maximum current sense V SENSE MAX threshold I Bias current SENSE EN/PWM section V Low level threshold IL V Low level threshold IL V High level threshold IH V High level threshold IH I EN/PWM pin current EN/PWM I EN/PWM pin current ...
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... Typical performance characteristics 5 Typical performance characteristics Figure 4. V vs. temperature FB Figure 6. I vs. temperature FB = 0.5 V OUT Figure 8. Efficiency vs. input voltage 2 LEDs Figure 9. 10/29 Figure 5. Maximum V Figure 7. I vs. temperature FB = GND OUT Efficiency vs. input voltage 4 LEDs Doc ID 18476 Rev 1 STLDC08 vs. temperature SENSE ...
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... STLDC08 Figure 10. Startup timing and dimming I vs. time, 2 LEDs 200 mA 2LEDs CC LED Figure 12. Startup timing and dimming I vs. time, 4 LEDs 300 mA 4LEDs CC LED Figure 14 1 LED Figure 11. Dimming EN/PWM = 200 Hz, 2 LEDs LED Figure 13. Dimming EN/PWM = 200 Hz, 4 LEDs ...
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... Feedback Feedback Comparator Comparator DRIVER DRIVER Doc ID 18476 Rev 1 VOUT VOUT Vcc Vcc 2Vcc 2Vcc Charge Charge Pump Pump 2Vcc 2Vcc DRV DRV SENSE SENSE Sensed Sensed Current Ramp Current Ramp OCP_TH OCP_TH FB FB 100 mV 100 mV PWMOUT PWMOUT AM07846v1 AM07846v1 STLDC08 ...
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... Detailed description 7.1 Main control loop The STLDC08 is an LED driver step-up controller dedicated to handheld equipment, having a typical voltage ranging from 0 1.5 V. The controller drives an N-channel Power MOSFET and implements a hysteretic current mode control with constant OFF time. Hysteretic operation eliminates the need for small signal control loop compensation. The control loop adapts the value of the inductor peak current as needed to deliver the desired current on the LED branch ...
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... The enable pin allows disabling and enabling of the device as well as brightness control of the LEDs by applying a PWM signal. In order to avoid visible flicker, the frequency of the PWM signal should be higher than 120 Hz. Changing the PWM duty cycle therefore changes the LED brightness. 14/ >1.9 V STLDC08 is >1.9 V STLDC08 is OUT OUT supplied by V supplied by V OUT ...
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... STLDC08 7.5 Dimming When PWMOUT goes to zero, the LED current immediately goes to zero and the energy stored in the coil is discharged on the output capacitor, causing an increase in the output voltage. As soon as the PWM goes back to high value, there is a big spike current on the LED. This could damage the LED itself. To avoid this, as soon as the input PWM signal goes to zero the controller immediately turns off the main switch (in order to discharge the coil current on the LED branch) ...
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... LED manufacturers generally recommend a value for LED current ripple ranging from LED average current. 16/ LED is compared with the internal precision 100 mV voltage reference − OUT D = × LED ) Doc ID 18476 Rev 1 STLDC08 resistor which guarantees FB time in order to obtain the ON FB ...
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... STLDC08 As a first approximation we choose the inductor ripple current the output current. Higher ripple current allows for smaller inductors, but it also increases the output capacitance for a given LED current ripple requirement. Conversely, lower ripple current can be obtained increasing the value of the inductance, and this enables a reduction of the output capacitor value ...
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... AVG ) − MAX MIN ) = − MAX + V V OUT D Δ AVG ) 2 Δ OUT L > SAT ) ( − MAX SENSE = MAX ) R R SENSE SENSE Doc ID 18476 Rev 1 STLDC08 and can L(PK) ...
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... STLDC08 Equation 11 Equation 12 Equation 13 If the R of the main Power MOSFET is used to sense the current on the inductor the DS (ON) following procedure must be performed to choose the Power MOSFET. During ON time, the SENSE comparator limits the voltage across the Power MOSFET to a nominal 100 mV. In ...
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... VOUT state ON state DVR DVR SENSE SENSE Rsense Rsense VOUT VOUT FB FB OFF state OFF state Doc ID 18476 Rev 1 STLDC08 C C OUT OUT LED LED OUT OUT LED LED rating DS ...
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... STLDC08 8.6 Schottky diode selection Schottky diodes, with their low forward voltage and fast recovery time, are the ideal choice to maximize efficiency. The output diode in a boost converter conducts current only when the power switch is OFF. The average current is equal to the output current and the peak current is equal to the peak inductor current ...
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... STPS2L30 Doc ID 18476 Rev 1 TP2 TP3 SW VOUT TP4 M1 1 SENSE Rs C6 Rfb = 200 mA Value Size 4.7 µF 6.3V 0805 10 µ 1206 10 nF, 6.3 V 0603 1 µ 0603 10µ SO-8 SMA 0.47 Ω 0805 0.047 Ω 0805 0 Ω STLDC08 LED M2 AM07900v1 ...
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... STLDC08 10 Layout suggestion Figure 22. Assembly layer Figure 23. Top layer Doc ID 18476 Rev 1 Layout suggestion 23/29 ...
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... Layout suggestion Figure 24. Bottom layer 24/29 Doc ID 18476 Rev 1 STLDC08 ...
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... STLDC08 11 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: ECOPACK® trademark. Doc ID 18476 Rev 1 Package mechanical data www ...
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... Package mechanical data Dim. Min 0.18 D 2.85 D2 2.20 E 2. 0.30 ddd 26/29 DFN10 (3x3 mm) mechanical data mm. Typ. Max. 0.90 1.00 0.02 0.05 0.65 0.80 0.20 0.25 0.30 3.00 3.15 3.00 3.15 1.75 0.50 0.40 0.50 0.08 Doc ID 18476 Rev 1 mils. Min. Typ. 31.5 35.4 0.8 21.7 25.6 7.9 7.1 9.8 112.2 118.1 86.6 112.2 118.1 55.1 19.7 11.8 15.7 7426335F STLDC08 Max. 39.4 2.0 31.5 11.8 124.0 124.0 68.9 19.7 3.1 ...
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... STLDC08 Tape & reel QFNxx/DFNxx (3x3) mechanical data Dim. Min 12 mm. Typ. Max. Min. 180 13.2 0.504 0.795 2.362 14.4 3.3 3.3 1 Doc ID 18476 Rev 1 Package mechanical data inch. Typ. Max. 7.087 0.519 0.567 0.130 0.130 0.043 0.157 0.315 ...
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... Revision history 12 Revision history Table 9. Document revision history Date Revision 22-Feb-2011 1 28/29 First release. Doc ID 18476 Rev 1 Changes STLDC08 ...
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... STLDC08 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. ...