STCS05DR

STCS05 0.5 A max constant current LED driver Datasheet - production data Description The STCS05 is a BiCMOS constant current source designed to provide a precise constant current starting from a varying input voltage source. The main target is to replace discrete components solution for driving LEDs in low voltage applications such as 5 V, 12 V or 24 V giving benefits in terms of precision, integration and reliability. SO-8 The current is set with external resistor up to 0.5 A with a ± 10 % precision; a dedicated pin allows implementing PWM dimming. Features An open-drain pin output provides information on load disconnection condition. • Up to 40 V input voltage • Less than 0.5 V voltage overhead • Up to 0.5 A output current • PWM dimming pin • Shutdown pin • LED disconnection diagnostic • Slope control with external cap Applications • LED constant current supplying for varying input voltages • Low voltage lighting • Small appliances LED lighting Table 1. Device summary Order code Package Packing STCS05DR SO-8 2500 parts per reel January 2022 This is information on a product in full production. DocID13969 Rev 5 1/16 www.st.com Contents STCS05 Contents 1 Pin configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 2 Maximum ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 3 Electrical characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 4 Timing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 5 Typical performance characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 6 Detail description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 7 6.1 Current setting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 6.2 Enable . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 6.3 PWM dimming . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 6.4 Diagnostic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 Application information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 7.1 Reverse polarity protection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 7.2 Thermal considerations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 8 Package mechanical data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 9 Revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 2/16 DocID13969 Rev 5 STCS05 Application diagram Application diagram Figure 1. Typical application diagram for 0.5 A LED current VIN 4.5V to 40V BAT46ZFILM RIN 100 ohm CBYP 0.1µF ON VCC PWM OFF ON OFF DRAIN STCS05 EN DISC Load disconnection (Open Drain output) DocID13969 Rev 5 GND CDRAIN 0.47µF FB RFB 0.2 ohm 3/16 16 Pin configuration 1 STCS05 Pin configuration Figure 2. Pin connections (top view) Table 2. Pin description Pin n° Symbol 1 VCC 2 PWM 3 EN 4 DRAIN 5 FB 6 GND Ground 7 N.C. In order to guarantee the device works properly it is mandatory to leave this pin floating 8 DISC Load disconnection flag (open drain) 4/16 Note Supply voltage PWM dimming input Shutdown pin Internal N-MOSFET drain External resistor connection for current set (N-MOSFET source) DocID13969 Rev 5 STCS05 2 Maximum ratings Maximum ratings Table 3. Absolute maximum ratings Symbol Parameter Value VCC DC supply voltage -0.3 to +45 VD Drain voltage -0.3 to +45 PWM, EN, DISC FB Logic pins Configuration pins Unit V -0.3 to + VCC + 0.3 V -0.3 to + 3.3 V ±2 kV ESD Human body model (all pins) TJ (1) Junction temperature -40 to 150 °C TSTG Storage temperature range -55 to 150 °C 1. TJ is calculated from the ambient temperature TA and the power dissipation PD according the following formula: TJ = TA + (PD x RthJA). See Figure 12 for details of max power dissipation for ambient temperatures higher than 25°C. Note: Absolute maximum ratings are those values beyond which damage to the device may occur. Functional operation under these conditions is not implied. Table 4. Thermal data Symbol Parameter SO-8 Unit RthJC Thermal resistance junction-case 20 °C/W RthJA Thermal resistance junction-ambient (1) 100 °C/W 1. This value depends from thermal design of PCB on which the device is mounted. DocID13969 Rev 5 5/16 16 Electrical characteristics 3 STCS05 Electrical characteristics Table 5. Electrical characteristics (VCC = 12 V; IO = 100 mA; TJ = -40 °C to 125 °C; VDRAIN = 1 V; CDRAIN = 1 µF; CBYP = 100 nF typical values are at TA = 25 °C, unless otherwise specified) Symbol VCC IO VFB Parameter Test conditions Min. VDROP DISC Thermal Protection Unit 4.5 40 V Output current range 1 500 mA Output current RFB = 0.2Ω Regulation (percentage with respect to VCC = 12 V) VCC = 4.5 to 40V, IO = 100mA; VDRAIN = 1V -1 Feedback Voltage IO = 0 to 0.5A 90 Quiescent current (Measured on VCC pin) Dropout voltage (VDRAIN to GND) LEAKDRAIN Drain leakage current TD Max. Supply voltage range 500 On Mode ICC Typ. +1 % 100 110 mV 450 750 Shutdown Mode; VCC = 5 to 12V 1 Shutdown Mode; VCC = 12 to 40V 3 IO = 100mA 0.12 0.16 IO = 0.5A 0.58 0.9 Shutdown; VDRAIN = 40V 10 VPWM rising, VCC = 12V 3 VPWM falling, VCC = 12V 1.2 Low level voltage ISINK = 5mA 0.2 Leakage current VDISC = 5V Load disconnection threshold (VDRAIN-GND) DISC Turn-ON 75 DISC Turn-OFF 110 Delay on PWM signal (see Figure 3) mA Shutdown temperature 155 Hysteresis 25 µA V µA µs 0.5 V 1 µA mV °C Logic Inputs (PWM and EN) VL Input low level VH Input high level Note: 6/16 0.4 1.2 V V EN, PWM leakage current VEN = 5V; VPWM = 5V 2 EN input leakage current VEN = 40V 60 PWM input leakage current VPWM = 40V 120 µA All devices 100 % production tested at TA = 25 °C. Limits over the operating temperature range are guaranteed by design. DocID13969 Rev 5 STCS05 4 Timing Timing Figure 3. PWM and output current timing PWM 90% Current 10% TD Trise TD Tfall Figure 4. Block diagram High Voltage 45 V VCC Preregulator 3.3 V Low Voltage 3.3 V H.V. 45 V Thermal Shutdown Bandgap 1.23 V DISC Shutdown all blocks + 75 mV EN PWM Enable Input PWM Input Enable & PWM Logic Disc comp DRAIN + Logic 100 mV - Driver Comp GND FB DocID13969 Rev 5 7/16 16 Typical performance characteristics 5 STCS05 Typical performance characteristics Figure 5. IDRAIN vs. VCC, TA = 25 °C Figure 6. IDRAIN vs. RSET 1000 IDRAIN [mA] 100 10 1 0.1 1 10 100 RFB [Ω] 8/16 Figure 7. IDRAIN vs. temperature Figure 8. VDROP (including VFB) vs. temperature Figure 9. ICC vs. temperature Figure 10. ICC vs. VCC DocID13969 Rev 5 STCS05 6 Detail description Detail description The STCS05 is a BiCMOS constant current source designed to provide a precise constant current starting from a varying input voltage source. The main target is to replace discrete components solution for driving LEDs in low voltage applications such as 5 V, 12 V or 24 V giving benefits in terms of precision, integration and reliability. 6.1 Current setting The current is set with an external sensing resistor connected to the FB pin. The feedback voltage is 100 mV, then a low resistor value can be chosen reducing power dissipation. A value between 1 mA and 500 mA can be set according to the resistor value, the resulting output current has a tolerance of ± 10 %. For instance, should one need a 350 mA LEDs current, RF should be selected according to the following equation: RF = VFB / ILEDs = 100 mV / 350 mA = 284 mΩ 6.2 Enable When the enable pin is low the device completely off thus reducing current consumption to less than 1 µA. When in shutdown mode, the internal main switch is off. 6.3 PWM dimming The PWM input allows implementing PWM dimming on the LED current; when the PWM input is high the main switch will be on and vice versa. A typical frequency range for the input is from few Hertz to 50 kHz. The maximum dimming frequency is limited by the minimum rise/fall time of the current which is around 4 µs each. Above 50 kHz the current waveforms starts assuming a triangular shape. While the PWM input is switching, the overall circuitry remains on, this is needed in order to implement a short delay time TD (see Figure 3) Since the PWM pin is controlling just the main switch, the overall circuitry is always on and it is able to control the delay time between the PWM input signal and the output current in the range of few µs, this is important to implement synchronization among several light LED sources. 6.4 Diagnostic When STCS05 is in on mode (EN is high), the device is able to detect disconnection or fail of the LED string monitoring VDRAIN pin. If VDRAIN is lower than 75 mV the DISC pin is pulled low regardless the PWM pin status. This information can be used by the system to inform that some problem happens in the LEDs. DocID13969 Rev 5 9/16 16 Application information STCS05 7 Application information 7.1 Reverse polarity protection STCS05A must be protected from reverse connection of the supply voltage. Since the current sunk from VCC pin is in the range of 450 µA a small diode connected to VCC is able to protect the chip. Care must be taken for the whole application circuit, especially for the LEDs, in fact, in case a negative voltage is applied between VIN and GND, a negative voltage will be applied to the LED string that must have a total breakdown voltage higher than the negative applied voltage in order to avoid any damage. Figure 11. Reverse polarity condition VIN BAT46 or similar VCC DRAIN PWM EN DISC + 7.2 GND FB Thermal considerations The STCS05 is able to control a LED current up to 500 mA and able to sustain a voltage on the drain pin up to 40 V. Those operating conditions are however limited by thermal constraints, the thermal resistances shown in the thermal data section is the typical ones. The power dissipation in the device can be calculated as follow: PD = (VDRAIN - VFB) x ILED + (VCC x ICC) basing on this and on the thermal resistance and ambient temperature, the junction temperature can be calculated as: TJ = RthJA x PD + TA A typical application could be: – Input voltage: 12 V; – 3 white LEDs with an typical VF = 3.6 V; – LEDs current: 350 mA; – Package: SO-8; – TA = 50 °C; 10/16 DocID13969 Rev 5 STCS05 Application information In this case VDRAIN = 12 - 3 x 3.6 = 1.2 V PD = (1.2 - 0.1) x 0.35 + 12 x 0.5 x 10-3 = 0.385 + 6 x 10-3 = 391 mW The junction temperature will be: TJ = 100 x 0.391 + 50 = 89 °C. The following pictures show the maximum power dissipation according to the ambient temperature: Figure 12. Maximum power dissipation vs. TA for SO-8 1.40 RthJA = 100 [°C/W] PDMAX [W] 1.20 1.00 0.80 0.60 PDMAX = (TJMAX-TA)/RthJA 0.40 0.20 25 35 45 55 65 75 85 95 105 115 125 [°C] DocID13969 Rev 5 11/16 16 Package mechanical data 8 STCS05 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® is an ST trademark. 12/16 DocID13969 Rev 5 STCS05 Package mechanical data SO-8 mechanical data Dim. mm. Min. Typ. inch. Max. Min. Typ. Max. A 1.35 1.75 0.053 0.069 A1 0.10 0.25 0.04 0.010 A2 1.10 1.65 0.043 0.065 B 0.33 0.51 0.013 0.020 C 0.19 0.25 0.007 0.010 D 4.80 5.00 0.189 0.197 E 3.80 4.00 0.150 0.157 e 1.27 0.050 H 5.80 6.20 0.228 0.244 h 0.25 0.50 0.010 0.020 L 0.40 1.27 0.016 0.050 k ddd 8° (max.) 0.1 0.04 0016023/C DocID13969 Rev 5 13/16 16 Package mechanical data STCS05 Tape & reel SO-8 mechanical data mm. inch. Dim. Min. A Max. Min. 330 13.2 Typ. Max. 12.992 C 12.8 D 20.2 0.795 N 60 2.362 T 14/16 Typ. 0.504 22.4 0.519 0.882 Ao 8.1 8.5 0.319 0.335 Bo 5.5 5.9 0.216 0.232 Ko 2.1 2.3 0.082 0.090 Po 3.9 4.1 0.153 0.161 P 7.9 8.1 0.311 0.319 DocID13969 Rev 5 STCS05 9 Revision history Revision history Table 6. Document revision history Date Revision Changes 03-Oct-2007 1 Initial release. 15-Feb-2008 2 Modified: Figure 1 on page 3, Figure 4 on page 7, Figure 12 on page 11. 05-May-2008 3 Modified: Table 2 on page 4, pin 7 description. 02-Jul-2008 4 Modified: Table 5 on page 6. 20-Jan-2022 5 Updated: Applications on the cover page. DocID13969 Rev 5 15/16 16 STCS05 IMPORTANT NOTICE – PLEASE READ CAREFULLY STMicroelectronics NV and its subsidiaries (“ST”) reserve the right to make changes, corrections, enhancements, modifications, and improvements to ST products and/or to this document at any time without notice. Purchasers should obtain the latest relevant information on ST products before placing orders. ST products are sold pursuant to ST’s terms and conditions of sale in place at the time of order acknowledgement. Purchasers are solely responsible for the choice, selection, and use of ST products and ST assumes no liability for application assistance or the design of Purchasers’ products. No license, express or implied, to any intellectual property right is granted by ST herein. Resale of ST products with provisions different from the information set forth herein shall void any warranty granted by ST for such product. ST and the ST logo are trademarks of ST. For additional information about ST trademarks, please refer to www.st.com/trademarks. All other product or service names are the property of their respective owners. Information in this document supersedes and replaces information previously supplied in any prior versions of this document. © 2022 STMicroelectronics – All rights reserved 16/16 DocID13969 Rev 5