STCS05ADR

STCS05A 0.5 A max constant current LED driver Datasheet - production data Description The STCS05A 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. An external capacitor allows setting the slope for the current rise from tens of microseconds to tens of milliseconds allowing reduction of EMI. Features • Up to 40 V input voltage • Less than 0.5 V voltage overhead An open-drain pin output provides information on load disconnection condition. • Up to 0.5 A output current • PWM dimming pin • Shutdown pin • LED disconnection diagnostic Applications • LED constant current supplying for varying input voltages • Low voltage lighting • Small appliances LED lighting Table 1. Device summary Order code Package Packing STCS05ADR SO-8 2500 parts per reel April 2022 This is information on a product in full production. DocID14510 Rev 4 1/18 www.st.com Contents STCS05A Contents 1 Application diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 2 Pin configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 3 Maximum ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 4 Electrical characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 5 Timing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 6 Typical performance characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 7 Detail description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 8 7.1 Current setting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 7.2 Enable . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 7.3 PWM dimming . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 7.4 Diagnostic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11 Application information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 8.1 Reverse polarity protection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 8.2 Thermal considerations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 9 Package mechanical data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 10 Revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 2/18 DocID14510 Rev 4 STCS05A 1 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 STCS05A CDRAIN 0.47µF EN DISC Load disconnection (Open Drain output) SLOPE GND CSLOPE 10nF DocID14510 Rev 4 FB RFB 0.2 ohm 3/18 18 Pin configuration 2 STCS05A 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 7 SLOPE 8 DISC 4/18 Note Supply voltage PWM dimming input Shutdown pin Internal N-MOSFET drain Feedback input. The control loop regulates the current in such a way that the average voltage at the FB input is 100 mV (nominal). The cathode of the LED and a resistor to ground to set the LED current should be connected at this point. Ground Capacitor for slope control Load disconnection flag (open drain) DocID14510 Rev 4 STCS05A 3 Maximum ratings Maximum ratings Table 3. Absolute maximum ratings Symbol Parameter VCC Value Unit DC supply voltage -0.3 to +45 DRAIN Drain pin -0.3 to +45 PWM, EN, DISC Logic pins -0.3 to + VCC + 0.3 V -0.3 to + 3.3 V Human body model (all pins) ±2 kV SO-8 TA = 25°C (1) 1.25 W Junction temperature -40 to 150 °C Storage temperature range -55 to 150 °C SLOPE, FB Configuration pins ESD Power Dissipation TJ TSTG V 1. See Figure 16 for details of max power dissipation for ambient temperature 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. DocID14510 Rev 4 5/18 18 Electrical characteristics 4 STCS05A 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 TD DISC Thermal Protection Unit 4.5 40 V Output current range 1 500 mA Output current RFB = 0.2 Ω Regulation (percentage with respect to VCC = 12 V) VCC = 4.5 to 40 V, IO = 100 mA; VDRAIN = 1 V -1 Feedback Voltage IO = 0 to 0.5 A 90 Quiescent current (Measured on VCC pin) Dropout voltage (VDRAIN to GND) LEAKDRAIN Drain leakage current TR/TF Max. Supply voltage range 500 On Mode ICC Typ. Rise/Fall time of the current on PWM transition +1 % 100 110 mV 450 750 Shutdown Mode; VCC = 5 to 12 V 1 Shutdown Mode; VCC = 12 to 40 V 3 IO = 100 mA 0.12 0.16 IO = 0.5 A 0.58 0.9 Shutdown; VDRAIN = 40 V 10 CSLOPE = 10 nF, TJ = -40 °C to 105 °C 800 VPWM rising, VCC = 12 V CSLOPE = floating 3 VPWM falling, VCC = 12 V CSLOPE = floating 1.2 Low level voltage ISINK = 5 mA 0.2 Leakage current VDISC = 5 V Load disconnection threshold (VDRAIN-GND) DISC Turn-ON 75 DISC Turn-OFF 110 Delay on PWM signal (see Figure 3) mA µA V µA µs µs Shutdown temperature 155 Hysteresis 25 0.5 V 1 µA mV °C Logic inputs (PWM and EN) VL Input low level VH Input high level Note: 6/18 0.4 1.2 V V EN, PWM leakage current VEN = 5 V; VPWM = 5 V 2 EN input leakage current VEN = 40 V 60 PWM input leakage current VPWM = 40 V 120 µA All devices 100 % production tested at TA = 25 °C. Limits over the operating temperature range are guaranteed by design. DocID14510 Rev 4 STCS05A 5 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 Enable Input PWM PWM Input Enable, PWM & Slope controll Logic Disc comp DRAIN + Logic 100 mV Comp GND Slope Control Driver FB SLOPE DocID14510 Rev 4 7/18 18 Typical performance characteristics 6 STCS05A 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] 8/18 Figure 7. IDRAIN vs. VCC, TA = 25 °C Figure 8. VDROP (including VFB) vs. temperature Figure 9. ICC vs. temperature Figure 10. ICC vs. VCC DocID14510 Rev 4 STCS05A Typical performance characteristics Figure 11. Trise/Tfall vs. CSLOPE Figure 12. Turn-on time IDRAIN = 80 mA - CSLOPE = 10nF - TA = 25° C VPWM 2V/DIV IDRAIN 20mA/DIV VDRAIN 1V/DIV Time 210µsec/DIV Figure 13. Rise time Figure 14. Fall time IDRAIN = 80 mA - CSLOPE = 10nF - TA = 25° C IDRAIN = 80 mA - CSLOPE = 10nF - TA = 25° C VPWM 2V/DIV VPWM 2V/DIV IDRAIN 20mA/DIV IDRAIN 20mA/DIV VDRAIN 1V/DIV VDRAIN 1V/DIV Time 200µsec/DIV Time 200µsec/DIV DocID14510 Rev 4 9/18 18 Detail description 7 STCS05A Detail description The STCS05A 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. 7.1 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 7.2 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. 7.3 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 (obtained with CSLOPE = 0) 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 two important features: short delay time and controlled slope for the current. 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. The rise and fall slope of the current is controlled by the CSLOPE capacitor. The rise and fall time are linear dependent from the CSLOPE capacitor value (see graph in typical characteristics). A controlled rise time has two main benefits: reducing EMI noise and avoid current spike at turn on. When CSLOPE is left floating, the internal switch is turned on at maximum speed, in this condition an overshoot can be present on the LED current before the system goes into regulation. 10/18 DocID14510 Rev 4 STCS05A 7.4 Detail description Diagnostic When STCS05A 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. DocID14510 Rev 4 11/18 18 Application information STCS05A 8 Application information 8.1 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 15. Reverse polarity condition VIN BAT46 or similar DRAIN VCC PWM EN DISC + 8.2 SLOPE GND FB Thermal considerations The STCS05A 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; 12/18 DocID14510 Rev 4 STCS05A Application information – TA = 50 °C; 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 For a correct operation of the chip, in this example the ambient temperature must not exceed about 110 °C. The following pictures show the maximum power dissipation according to the ambient temperature: Figure 16. 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] DocID14510 Rev 4 13/18 18 Package mechanical data 9 STCS05A 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. 14/18 DocID14510 Rev 4 STCS05A 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 DocID14510 Rev 4 15/18 18 Package mechanical data STCS05A 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 16/18 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 DocID14510 Rev 4 STCS05A 10 Revision history Revision history Table 6. Document revision history Date Revision Changes 04-Mar-2008 1 Initial release. 02-Jul-2008 2 Modified: Table 5 on page 6. 20-Jan-2022 3 Updated: Applications on the cover page. 21-Apr-2022 4 Updated: Power dissipation value in Table 3 and Section 8.2. DocID14510 Rev 4 17/18 18 STCS05A 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 18/18 DocID14510 Rev 4