austriamicrosystems AG is now ams AG The technical content of this austriamicrosystems datasheet is still valid. Contact information: Headquarters: ams AG Tobelbaderstrasse 30 8141 Unterpremstaetten, Austria Tel: +43 (0) 3136 500 0 e-Mail: [email protected] Please visit our website at www.ams.com austriamicrosystems AS3693B Product specification, Preliminary AS3696 4 channel white LED controller for 3D-LCD backlight General Description 2x2 Channel LED driver Output current only limited by external FET Build in shunt regulator Absolute current accuracy +/- 1% Channel to channel accuracy +/- 1% Normal Mode Linear current control with external voltage Digital PWM control with PWM input Build in PWM-generator with analog duty cycle control 3D Mode Linear current control with external voltage Digital PWM control with 2 PWM inputs Open LED detection Short LED detection and auto-turnoff Temperature shutdown 2x automatic supply regulation feedback Package QFN 32pin 5x5mm, 0.5mm pitch Package TQFP 32pin 7x7mm, 0.8mm pitch Package SOIC 28pin lv am lc s on A te G nt st il al id The AS3696 is a 4 channels precision LED controller with PWM inputs or internal PWM generator for driving external FETs in LCD-backlight panels. Build in safety features include thermal shutdown as well as open and short LED detection. Applications • LED backlighting for 3D- LCD – TV sets and monitors 1 Block Diagram Vsupply VDD xFAULT FB12 FB34 V2_5 D1 D3 SMPS G1 G3 feedback S1 S3 D2 D4 Fault detectors G2 G4 S2 ca S4 AS3696 Rosc ni Cosc Oscillator Te ch Vduty 3D_PWM12 3D_PWM34 3D_MODE PWM control Reference Vshort Vfb Vref Vset2 Vset1 xPD PWM SEL www.austriamicrosystems.com EPAD VSS Rev 1.10 / 1011-04-04 Sel_PPTrim 1 - 16 austriamicrosystems AS3696 2 Typical Application R2 SMPS2 R2 SMPS1 R1 R1 lv al id Rfb Rfb am lc s on A te G nt st il 24V Vduty PWM SEL 3D_PWM12 3D_PWM34 3D_MODE D4 G4 S4 D3 G3 S3 VDD D2 G2 S2 Cvdd 2.2uF D1 G1 S1 Rvdd Precision current sink AS3696 PWM controller FB12 FB34 Safety features Supply feedback xPD xFault Vref Vset1 Vset2 Vref Vfb Vshort V2_5 VSS Epad Cfb 1uf-10uF Oscillator Rosc Cosc Sel_PPTrim Te ch ni ca 2.2uF www.austriamicrosystems.com Rev 1.10 / 1011-04-04 2 - 16 Cfb 1uf-10uF austriamicrosystems AS3696 3 Electrical Characteristics 3.1 Absolute Maximum Ratings Stresses beyond those listed may cause permanent damage to the device. These are stress ratings only and functional operation of the device at these or any other conditions beyond those indicated in Section “Electrical Characteristics” is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability. Symbol Parameter Min Max Unit Note Supply voltage -0.3 5.4 V VIN_2.5V Maximum voltage -0.3 V2_5 +0.3V V Applicable for 2.5V pins VIN_5V Maximum voltage -0.3 VDD +0.3V V Applicable for 5V pins VIN_50V Maximum voltage -0.3 50 V Applicable for 50V pins Ilatch Latch-Up immunity -100 +100 mA Norm: EIA/JESD78 TSTRG Storage Temperature Range -55 150 °C Maximum Junction Temperature Humidity 5 85 % Non condensing VESD_LV Electrostatic Discharge on all pins ( except D1...D4 ) -2000 2000 V Norm: MIL 883 E Method 3015 Human body model VESD_HV Electrostatic Discharge on pins D1 ... D4 -4000 4000 V Norm: MIL 883 E Method 3015 Human body model TBODY Body Temperature during Soldering 260 °C according to IPC/JEDEC J-STD020C 3.2 (1) lv (2) (3) am lc s on A te G nt st il Note: al id VDDMAX Voltage limit due to internal shunt regulator. (1) Pins: V2_5, Vfb (2) Pins: All pins except V2_5, D1-D4, Vfb (3) Pins: D1 – D4 Operating Conditions Symbol Conditions Rthja Thermal resistance junction – ambient QFN32 PDERATE PT Derating Factor QFN32 Tamb Min Typ Max 30 Unit °C/W mW/ °C 33 Ambient Temperature -30 85 °C Junction Temperature -30 115 °C ch Tj ca Parameter ni 3.2.1 General 3.2.2 Power supply Parameter Conditions Te Symbol VDDint Shunt regulator operation. Supply current has Supply Voltage VDD to be limited between 10mA and 30mA by shunt regulator operation external resistor IDDmax Maximum shunt regulator current VDDext Supply Voltage VDD www.austriamicrosystems.com no shunt regulator operation. No external current limiting resistor needed Rev 1.10 / 1011-04-04 Min Typ Max Unit 5.0 5.2 5.5 V 30 mA 4.9 V 4.0 3 - 16 4.5 austriamicrosystems AS3696 Parameter Conditions Min VDD_POR Power on reset level Circuit stays in power down until VDD_POR is reached. G1 – G4 is pulled to GND during power down 2.4 IDD_q Quiescent current VDD= 5V, Default setting, PWM = 0 1 IDD_r Supply current VDD = 5V, PWM = 240Hz, Duty = 50% 2.5 10 mA V2_5 V2_5 regulator output 2.5 2.6 V I2_5 V2_5 output current 1 mA Vref Reference voltage 1.26 V Rvref Output resistance Vref 2.4 1.24 Typ 1.25 300 3.2.3 Current outputs Parameter Min Vdx Output voltage pins Dx Rdx Input resistance in Dx PWM = 0 U_DX=16V PWM = 1 1 0.1 Vgx Max output voltage pin Gx Igx = 1mA VDD0.5 Igx Max output current pin Gx Rsx Input resistance pin Sx Typ 3.0 V mA Ω Max Unit 50 V MΩ MΩ VDD V 1 mA am lc s on A te G nt st il Conditions Unit lv Symbol Max al id Symbol Iled_250 Ich_250 1 MΩ Current accuracy Trimmed during production ILED =100mA, Temp = 25°C, external NMOS-Transistor used, Vset1 = 250mV (excluding error of external Rset) -1.0 +1.0 % Channel to channel Current accuracy Trimmed during production ILED =100mA, Temp = 25°C, external NMOS-Transistor used, Vset1 = 250mV (excluding error of external Rset) -1.0 +1.0 % ca Tjunction = -20°C to +100°C (1) Vset1 = 200mV to 500mV Iled_all Current accuracy -2.0 +2.0 % external NMOS-Transistor used, (excluding error of external Rset) Note: (1) It is not recommended to use Vset < 200mV in order to minimize influences from PCB-layout and noise. Symbol ni 3.2.4 Feedback circuit, fault detectors Parameter Conditions Min Typ Feedback current maximum RFBmin Minim output resistance VDx = 0.3V 300 IFB_g FB transconductance IFB_g = ∆IFB/ ∆VDx -3 Vfb Feedback voltage trip point Vshort Short LED detector Voltage Te ch IFBmax Tovtemp 300 Unit uA 1000 Ω mA/V Trip voltage at Pins Dx 0 3 V Short LED detection level voltage Short will be detected if: 0 2 V 150 °C ((V_Dx -VsetX) /5 + VsetX) > Vshort Over temperature limit www.austriamicrosystems.com Max 130 Rev 1.10 / 1011-04-04 4 - 16 140 austriamicrosystems AS3696 Symbol Parameter Conditions Min Over termperature hysteresis Thyst Typ Max 10 Unit °C 3.2.5 PWM-inputs Symbol Parameter Conditions Min fPWM PWM-input frequency Pins: PWM, 3D_PWM12, 3D_PWM34 0 Typ Conditions Min Typ Max Unit 1 kHz Symbol Parameter UrefH Reference Voltage high 3.1 3.2 UrefL Reference Voltage low 0.0 0.1 Parameter Min VIH High Level Input voltage VIL Max Unit 1.3 VDD V Low Level Input voltage -0.3 0.8 V VoH High Level output voltage VDD0.3 VoL Low Level output voltage VoL_PD Low level output voltage open drain outputs R_pu Input resistance PullUp inputs 300 kΩ R_pd Input resistance PullDown inputs 300 kΩ 3.3 Typ V I=mA VDD0.3 V I=mA VDD0.3 V I=mA VDD 7V GND VDD 7V ca Digital inputs 3.3 V 0.2 V Note Pins equivalent circuit VDD Unit am lc s on A te G nt st il Symbol Max lv 3.2.7 Digital pins al id 3.2.6 Oscillator GND VDD ni Digital inputs Pull up 7V GND VDD ch Digital inputs Pull Down 7V GND VDD Te Digital outputs push/pull www.austriamicrosystems.com 7V GND Rev 1.10 / 1011-04-04 5 - 16 austriamicrosystems AS3696 VDD Digital output open drain 7V GND 4 Detailed Block description Current outputs al id 4.1 Optional: <20V Vshort FBx debounce 100ms Vfb Dx Short Monitor 120k VDD am lc s on A te G nt st il auto turnoff lv HV-cascode 50V 30k PWM_int OTA Vset1 Vset2 200mV - 500mV PWM_int 3D_Mode A1 Vset_int Slew Rate control 200mV - 500mV feedback turnoff debounce 100ms Open Monitor Gx Sx Rset Vset_int/2 4.1.1 Precision current sink All current sinks are built with an internal error amplifier A1 and an external power transistor. The external transistor should be a NMOS type to keep the current accuracy. The output current during PWM=1 can be calculated: in normal mode ( 3D_Mode = 0 ) in 3D mode ( 3D_Mode = 1 ) ca 4.1.2 Output voltage monitoring ch ni In order to monitor the proper DCDC output voltage the voltage at pin “Dx” is measured during PWM=1. If this voltage is too low a comparator turns on an transconductance amplifier which is able to control the output voltage of the external power supply via pin FB1 or FB2. 4.1.3 Open LED detection Te If a LED-string is broken the voltage at pin Dx gets lower than Vset_int/2. This status is detected and accumulated by a comparator during PWM=1. If the accumulated status lasts longer than 100ms, a fault is indicated and the corresponding power feedback function is turned off. After 500ms the fault is reset and the detection starts again. For proper detection the PWM high time has to be longer than 500us. 4.1.4 Short LED detection Shorted LEDs in a LED-string will cause higher voltage at pin “Dx”. A higher voltage during PWM=1 is detected by a comparator and will trigger a “short LED detection” fault. The duration of the fault is www.austriamicrosystems.com Rev 1.10 / 1011-04-04 6 - 16 austriamicrosystems AS3696 accumulated and if the time exceeds 100ms a fault is indicated and the output is turned off. If the hightime of the waveform is shorter than 100ms it will take more periods to trigger this fault. After 500ms the channel is turned on again. A short will be detected if: ((V_Dx -VsetX) /5 + VsetX) > Vshort For proper detection the PWM high time has to be longer than 500us. 4.2 PWM controller “3DMode” 0 “SEL” Mode Comment 0 External PWM is used as PWM_INT 0 1 Normal PWM external Normal PWM internal 1 X Vref_INT Vset1 Vset1 lv PWM-frequency is generated by internal oscillator PWM-duty cycle is set by voltage on pin “Vduty” Vduty can either be an external voltage ( PWM=0 ) or can be derived from the PWM signal by filtering with an ext capacitor 3D_PWM12 is used for driving Channels 1 and 2 3D_PWM34 is used for driving Channels 3 and 4 Vset2 am lc s on A te G nt st il 3D mode al id The PWM controller can operate in normal mode or 3D mode. Depending on the mode different output currents can be set. Cosc Rosc Oscillator Vduty 100k PWM Sel PWM_INT Ch1/Ch2 3D_PWM12 PWM_INT Ch3/Ch4 3D_PWM34 Vref_INT ca Vset1 Vset2 3D_Mode 4.3 Oscillator Te ch ni The build in oscillator can be used to generate internal PWM frequencies. The external Capacitor is charged with the current 1.24V/Rosc and discharged with the current 1.24V*10/Rosc. 1*Iosc UrefH UrefL UrefH 3.2V 10*Iosc Iosc = 1.24V/Rosc Rosc Rosc 1.24V Ud Cosc UrefL 0.1V Cosc 3.1, www.austriamicrosystems.com . , Rev 1.10 / 1011-04-04 T2 T1 ! . 7 - 16 austriamicrosystems AS3696 "#$ The Oscillator frequency can be calculated: 4.4 . %. ! !.%&%& [Hz] Power supply The device has a build in electronic Zener-diode at pin VDD for building a shunt regulator. To obtain a 5.2V regulated supply, a series resistor Rvdd has to be connected in series to the internal zener diode. An external capacitor Cvdd is used to filter the supply on the pin VDD. al id Vsupply Rvdd VDD Cvdd 2.2uF Regulator 5.2V am lc s on A te G nt st il GND lv Shunt The external resistor Rvdd has to be calculated according to the following formula: '(( )*++,-. 0. !12 Vsupply...Minimum Supply voltage 8 Power dissipation of Rvdd; 3 4 5)*++,- . 0, 7 9:: To ensure proper operation the minimum supply voltage should be choosen as Vsupply. If a stable supply voltage between 4V and 5V is available in the system this supply can also be used for VDD. In that case there is no need for the series resistor Rvdd. 4.5 Safety features 4.5.1 Temperature shutdown xPD input ni 4.5.2 ca If the die temperature reaches 140°C all outputs are turned off. If the die temperature goes below 130°C the outputs are turned on again. Te ch In addition to the build in power on reset circuit there is an external power down input “xPD” available. This gives the possibility to keep the outputs turned off until all blocks of the LED-driver circuits are fully working ( DCDC, MCU ... ) www.austriamicrosystems.com Rev 1.10 / 1011-04-04 8 - 16 austriamicrosystems AS3696 4.6 Reference circuit Temp POR 4.0V to 5.2V analog supply VDD 2.5V digital supply LDO Shunt Regulator 5.2V Voltage Ref V2_5 Vref The reference circuit generates an internal supply voltage of 2.5V for the digital logic. Dynamic feedback control lv 4.7 al id GND am lc s on A te G nt st il The output of pins “FB12” and “FB34” can be used to control any external power supply for best power efficiency. Every power supply senses its output voltage with a resistive voltage divider. This voltage divider can be modified to set the output voltage between a minimum output voltage VMIN and a maximum output voltage VMAX. The design of the dynamic feedback control is done in 3 steps. Step 1: Set the resistors R1,R2 in the power supply according to the minimum output voltage Vdcdc_MIN R1 SMPS sense R2 ;<=>?@ A C B D Step 2: Add the Resistors R3 in the power supply according to the maximum output voltage Vdcdc_MAX R1 SMPS sense R2 R3 A B || %C || % D ca ;<=>2E ni Step 3: Connect R3 to the feedback pin “FBxx”. C1 should be chosen according to the speed requirements of the feedback loop. Vdcdc_MIN to Vdcdc_MAX R1 sense ch SMPS R3 Te R2 AS369x Current Into FB-pin 300R 300uA -3mA/V FB C1 1uF-10uF Feedback speed V_FB-0.1v V_FB Voltage Dx The characteristic of the feedback function can be seen in the diagram. The final output voltage of is determined by the setting of VFB and the current that is drawn from the external voltage divider. www.austriamicrosystems.com Rev 1.10 / 1011-04-04 9 - 16 austriamicrosystems AS3696 5 Pinout and Packaging 5.1 Pinout QFN32, TQFP32 Pin Name QFN Package Pin Name TQFP package Pin Type Description 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 EP D1 G1 V2_5 Vfb Vduty FB12 FB34 Vref Vset1 Vset2 Rosc Cosc PWM 3D_Mode 3D_PWM12 3D_PWM34 SEL SEL_PPtrim xFAULT xPD Vshort VDD G4 D4 S4 S3 D3 G3 G2 D2 S2 S1 VSS D1 G1 V2_5 Vfb Vduty FB12 FB34 VSS Vset1 Vset2 Rosc Cosc PWM 3D_Mode 3D_PWM12 3D_PWM34 SEL SEL_PPtrim xFAULT xPD Vshort VDD G4 D4 S4 S3 D3 G3 G2 D2 S2 S1 AIO AIO AIO AIO AIO AIO AIO AIO AIO AIO AIO AIO Connect to Drain of external Transistor Connect to Gate of external Transistor Supply output. Connect 2.2uF bypass capacitor to GND Trip point voltage for outputs D1 – D4 Analog duty cycle control input Power supply feedback output1 and output2 Power supply feedback output3 and output4 Reference voltage output (QFN ), VSS ( TQFP ) Reference voltage input in normal mode Reference voltage input in 3D mode Resistor of RC-oscillator Capacitor of RC-oscillator PWM input Mode select input PWM input in 3D Mode for channel1 and channel2 PWM input in 3D Mode for channel3 and channel4 PWM input select in normal mode Connect to VSS. This pin is used for factory trimming. Fault output. Active low Power down input. Active low Short LED detection threshold voltage Shunt voltage regulator input. Connect to Gate of external Transistor Connect to Drain of external Transistor Connect to Source of External Transistor and to Resistor RSET Connect to Source of External Transistor and to Resistor RSET Connect to Drain of external Transistor Connect to Gate of external Transistor Connect to Gate of external Transistor Connect to Drain of external Transistor Connect to Source of External Transistor and to Resistor RSET Connect to Source of External Transistor and to Resistor RSET Exposed PAD. Connect to VSS ( QFN ) lv am lc s on A te G nt st il DI-PD DI-PD DI-PD DI-PD DI-PD DI-PD DO-OD DI-PU ca AIO AIO AIO AIO AIO AIO AIO AIO AIO AIO AIO AIO AIO Pinout SOIC28 ni 5.2 al id Pin Nr Pin Name SOIC Package Pin Type Description 1 2 3 4 5 6 7 8 9 10 11 12 G2 D2 S2 S1 D1 G1 V2_5 Vfb FB12 FB34 Vset1 Vset2 AIO AIO AIO AIO AIO AIO AIO AIO AIO AIO AIO AIO Connect to Gate of external Transistor Connect to Drain of external Transistor Connect to Source of External Transistor and to Resistor RSET Connect to Source of External Transistor and to Resistor RSET Connect to Drain of external Transistor Connect to Gate of external Transistor Supply output. Connect 2.2uF bypass capacitor to GND Trip point voltage for outputs D1 – D4 Power supply feedback output1 and output2 Power supply feedback output3 and output4 Reference voltage input in normal mode Reference voltage input in 3D mode Te ch Pin Nr www.austriamicrosystems.com Rev 1.10 / 1011-04-04 10 - 16 austriamicrosystems AS3696 DO-OD DI-PU AIO AIO AIO AIO AIO AIO AIO AIO Ground PWM input Mode select input PWM input in 3D Mode for channel1 and channel2 PWM input in 3D Mode for channel3 and channel4 Connect to VSS. This pin is used for factory trimming. Fault output. Active low Power down input. Active low Short LED detection threshold voltage Shunt voltage regulator input. Connect to Gate of external Transistor Connect to Drain of external Transistor Connect to Source of External Transistor and to Resistor RSET Connect to Source of External Transistor and to Resistor RSET Connect to Drain of external Transistor Connect to Gate of external Transistor al id AIO DI-PD DI-PD DI-PD DI-PD DI-PD lv VSS PWM 3D_Mode 3D_PWM12 3D_PWM34 SEL_PPtrim xFAULT xPD Vshort VDD G4 D4 S4 S3 D3 G3 Analog Pin DI Digital input DI-PU Digital input with pull up resistor DI-PD Digital input with pull down resistor DO Digital output DO-OD Digital output open drain am lc s on A te G nt st il AIO Te ch ni ca 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 www.austriamicrosystems.com Rev 1.10 / 1011-04-04 11 - 16 austriamicrosystems AS3696 Package Drawing QFN32 Te ch ni ca am lc s on A te G nt st il lv al id 5.3 www.austriamicrosystems.com Rev 1.10 / 1011-04-04 12 - 16 austriamicrosystems AS3696 Package Drawing TQFP32 Te ch ni ca am lc s on A te G nt st il lv al id 5.4 www.austriamicrosystems.com Rev 1.10 / 1011-04-04 13 - 16 austriamicrosystems AS3696 Package Drawing SOIC28 Te ch ni ca am lc s on A te G nt st il lv al id 5.5 www.austriamicrosystems.com Rev 1.10 / 1011-04-04 14 - 16 austriamicrosystems AS3696 6 Ordering information Part Number Marking Package Type Delivery Form Description Package size = 5x5mm, Pitch = 0.5mm, Pb-free; AS3696 QFN32 AS3696-ZTQT AS3696 TQFP32 Tape and Reel in Dry Pack Package size = 7x7mm, Pitch = 0.8mm, Pb-free; AS3696-DSOV AS3696 SOIC28 Tube in Dry Pack Pb-free; Te ch ni ca am lc s on A te G nt st il lv al id AS3696-ZQFT Tape and Reel in Dry Pack www.austriamicrosystems.com Rev 1.10 / 1011-04-04 15 - 16 austriamicrosystems AS3696 Copyright Copyright © 1997-2009, austriamicrosystems AG, Schloss Premstaetten, 8141 Unterpremstaetten, Austria-Europe. Trademarks Registered ®. All rights reserved. The material herein may not be reproduced, adapted, merged, translated, stored, or used without the prior written consent of the copyright owner. All products and companies mentioned are trademarks or registered trademarks of their respective companies. al id Disclaimer ca am lc s on A te G nt st il lv Devices sold by austriamicrosystems AG are covered by the warranty and patent indemnification provisions appearing in its Term of Sale. austriamicrosystems AG makes no warranty, express, statutory, implied, or by description regarding the information set forth herein or regarding the freedom of the described devices from patent infringement. Austriamicrosystems AG reserves the right to change specifications and prices at any time and without notice. Therefore, prior to designing this product into a system, it is necessary to check with austriamicrosystems AG for current information. This product is intended for use in normal commercial applications. Applications requiring extended temperature range, unusual environmental requirements, or high reliability applications, such as military, medical lifesupport or life-sustaining equipment are specifically not recommended without additional processing by austriamicrosystems AG for each application. For shipments of less than 100 parts the manufacturing flow might show deviations from the standard production flow, such as test flow or test location. The information furnished here by austriamicrosystems AG is believed to be correct and accurate. However, austriamicrosystems AG shall not be liable to recipient or any third party for any damages, including but not limited to personal injury, property damage, loss of profits, loss of use, interruption of business or indirect, special, incidental or consequential damages, of any kind, in connection with or arising out of the furnishing, performance or use of the technical data herein. No obligation or liability to recipient or any third party shall arise or flow out of austriamicrosystems AG rendering of technical or other services. ni Contact Information ch Headquarters austriamicrosystems AG A-8141 Schloss Premstätten, Austria Te T. +43 (0) 3136 500 0 F. +43 (0) 3136 5692 For Sales Offices, Distributors and Representatives, please visit: http://www.austriamicrosystems.com/contact www.austriamicrosystems.com Rev 1.10 / 1011-04-04 16 - 16