LSP7706 1.1A High Voltage Adjustable Current Regulator GENERAL DESCRIPTION FEATURES 0.8V Output Drop-out Voltage at 1.1Amp. 1.1Amp. Maximum Output Current. Output Current Controlled by External Resistor. 3us Fast Response Output Stage Enable Control. Output Pin Sustain Voltage Up To 75V. Supply Voltage Range 5V~50V. Green TO-263-5L package. The LSP7706 is a high voltage, low dropout current regulator for high power LED lighting. The LSP can handle the maximum output current up to 1.1Amp. The output current can also be varied by an external resistor. The output sink current could be switched off via OE pin. And the OE pin can also be used to control PWM dimming function. TO-263 green package is available to enhance the power dissipation of the driver. The LSP7706 also features with build-in thermal protection to prevent the chip from over heat damage. The adequate thermal pad in PCB area is required to control the junction temperature below 125C. TYPICAL APPLICATIONS High Power LED Driver RGB Full Color Power LED driver LCD Monitor/TV LED Backlight Driver LED Lighting LED Street Lamp / Table Lamp PIN ASSIGNMENT 5 OUT 5 4 OE 4 3 GND 3 2 ISET 1 VDD 2 1 TO-263-5L OUT OE GND ISET VDD TO-252-5L (Top View) (Top View) 5 OUT 4 OE 3 GND 2 ISET 1 VDD TO-220-5L (Top View) PIN DESCRIPTION Pin Number Pin Name 1 VDD Power supply. 2 ISET Output current set input. Connect a resistor from ISET to GND to set the LED bias current. 3 GND 4 OE 5 OUT Pin Function Ground. Output stage enable control pin. High enable the OUT pin. It can be left floating for normally on. The pin can also be used for PWM dimming function. Output pin. Sink current is decided by the current on RSET connected to ISET. 1.2V I OUT = I SET x 500 = x 500 RSET Thermal Pad Ground. Liteon Semiconductor Corp. 1/1 20090720_1.0 LSP7706 1.1A High Voltage Adjustable Current Regulator TYPICAL APPLICATION CIRCUIT ABSOLUTE MAXIMUM RATINGS Rating Unit Input Voltage, VDD 50 V Output Pin Sustain Voltage, VOUT 75 V Enable Voltage, VOE 13.2 V Maximum Operating Junction Temperature, TJ 150 C -65 to 150 C 260 C Parameters Storage Temperature Range Lead Temperature (soldering, 10 seconds) Note: Exceeding these ratings could cause damage to the device. All voltages are with respect to Ground. Currents are positive into, negative out of the specified terminal. THERMAL IMPEDIENCE TO-263, TO-220 Package: Thermal Resistance-Junction to Tab, JT 3 C /W Thermal Resistance-Junction to Ambient, JA 45 C /W TO-252 Package: Thermal Resistance-Junction to Tab, JT 7 C /W Thermal Resistance-Junction to Ambient, JA 80 C /W Junction Temperature Calculation: TJ = TA + (PD x JA). The JA numbers are guidelines for the thermal performance of the device/pc-board system. Connect the thermal pad to ground using a large pad or ground plane for better heat dissipation. All of the above assume no ambient airflow. Liteon Semiconductor Corp. 2/2 20090720_1.0 LSP7706 1.1A High Voltage Adjustable Current Regulator RECOMMENDED OPERATION Parameter Symbol Min Supply Voltage VDD Output Sink Current Typ Max Unit 5 50 V IOUT 0.3 1.1 A Operating Free-Air Temperature Range TA -40 +85 C Operating Junction Temperature TJ +125 C ELECTRICAL CHARACTERISTICS VDD=24V, TA=25C (Unless otherwise noted) Parameter Output Current Output Current Deviation Condition Min VOUT=0.5V, RSET=800 750 VOUT=0.7V, RSET=600 1000 Output Drop-out Voltage Note 1 Max 5 VOUT=0.7V, RSET=600 5 0.6 VOUT=0.8V, RSET=545 2.2 1100 RSET=800, IOUT=750mA 0.5 RSET=600, IOUT=1A 0.7 Unit mA VOUT=0.5V, RSET=800 ISET Pin Current Range Maximum Output Current Typ % mA mA V Load Regulation IOUT=750mA, VOUT=0.5V to 3V 8 mA Line Regulation IOUT=750mA, VOUT=0.5V, VDD= 5V to 50V, 6 mA Thermal Shut-down Junction Temperature Hysteresis 20 160 "Low" Input Voltage 0 0.8 V "High" Input Voltage 2 Min{VDD, 12} V "Low" Input Current -20 +20 A "High" Input Current -5.0 +5.0 A Output Enable Delay Time OE from Low to High, VOUT=0.5V, IOUT=750mA, 50% 5 S Output Disable Delay Time OE from High to Low, VOUT =0.5V, IOUT=750mA, 50% 5 S Supply Current Consumption 7 mA Note1: Output dropout voltage: 90% x IOUT @ VOUT=0.8V Liteon Semiconductor Corp. 3/3 20090720_1.0 LSP7706 1.1A High Voltage Adjustable Current Regulator FUNCTIONAL BLOCK DIAGRAM VDD OE OUT Band-gap Reference VREF Control Circuit FB A711 GND ISET TYPICAL CHARACTERISTICS Supply Current vs. Supply Voltage ISET Voltage vs. Junction Temperature 1.50 I OUT =1100mA 5.0 I OUT =900mA 4.0 I OUT =700mA 3.0 I OUT =500mA 2.0 I OUT =330mA 1.0 V DROP=0.8V TA=25C 0.0 0 20 40 1.40 ISET Voltage (V) Supply Current (mA) 6.0 1.30 1.20 1.10 V DD=24V 1.00 -50 60 0 Supply Voltage (V) 1200 I OUT =1100mA I OUT =900mA 600 I OUT =700mA 400 I OUT =500mA I OUT =330mA V DROP=1V TA=25C 0 0 1000 Output Current (mA) Output Current (mA) 800 200 100 150 Output Current vs. Dropout Voltage Output Current vs. Supply Voltage 1200 1000 50 Junction Temperature (C) VDD=24V TA=25C I OUT =1100mA 800 I OUT =900mA 600 I OUT =700mA 400 I OUT =500mA I OUT =330mA 200 0 20 40 0.00 60 2.00 3.00 Dropout Voltage (V) Supply Voltage (V) Liteon Semiconductor Corp. 1.00 4/4 20090720_1.0 LSP7706 1.1A High Voltage Adjustable Current Regulator RSET vs. Output Current 2 RSET (K ) 1.5 1 0.5 V DROP =1V TA =25C 0 300 500 700 900 Output Current (mA) 1100 FUNCTION DESCRIPTION LSP7706 is a high voltage, high current, and low dropout current regulator for maximum output current up to 1.1A. The OE pin is used for enabling/disabling the output stage of the chip. The current could be linearly adjusted through external resister, RSET, connected to ISET pin, or by PWM control via OE pin. Although the absolute maximum rating of OUT pin 75V, the dropout voltage between OUT pin and GND pin should not be too large when current is sinking because of the heat dissipation capability of the package and PCB layout. 1. Setting LED Current An external resistor RSET connected to ISET pin sets the sink current of OUT pin. The value of RSET is calculated by the following formula: I OUT = I SET 500 = 2. 1.2V 500 (mA) RSET ( K) PWM Dimming Control LSP7706 provides PWM dimming control function through OE pin. Basically, by changing the duty cycle of the PWM control signal, the ratio of LED ON-time to OFF-time can be changed. Consequently, larger duty cycle results in larger average current for driving LED and thus higher luminance. Ideally, the average LED driving current is in linear proportion to the duty cycle of the PWM control signal in spite of the frequency. However, due to the inherent propagation delay of the chip and the rising/falling time of the driving current, the deviation of the actual current from theoretical value will become larger when the PWM frequency gets higher. That is, if the PWM frequency exceeds certain recommended value, the effect of the fixed propagation delay and the rising/falling time of LED current on the linear relationship between the duty cycle and the average current will become more apparent. On the other hand, if the PWM frequency is too low, the flicker will become observable. Therefore, it is important to choose a suitable frequency for the PWM signal. Please refer to the following timing chart & table for the limitation of maximum dimming frequency. It is determined by the minimum duty ratio, DMIN, and the minimum LED "ON" time, tON,MIN. The maximum dimming frequency, fPWM, can be calculated by the following formula: 1 f PWM ,MAX = t ON ,MIN DMIN Where, duty ratio is defined as: D= t ON t ON + t OFF Liteon Semiconductor Corp. 5/5 20090720_1.0 LSP7706 1.1A High Voltage Adjustable Current Regulator tON tOFF VOE 50%*VOE OE tpLH tpHL tR tF IOUT ILED 50%*IOUT Characteristic 3. Symbol Min Typ Max Unit LED "ON" Period (OE Pin Control Signal) tON 5 us LED "OFF" Period (OE Pin Control Signal) tOFF 5 us Propagation Delay Time (Output Current from "L" to "H") tpLH 1.5 3 us Propagation Delay Time (Output Current from "H" to "L") tpHL 1.5 3 us Output Current Rising Time (Rising from 10% to 90%) tR 1.5 3 us Output Current falling Time (Falling from 90% to 10%) tF 1.5 3 us DC Voltage Input Any DC voltage level between 5V to 50V could be adopted as power source VDD for typical application of LSP7706 as long as VDD is larger than the total forward voltage drop of the LED string by the minimum dropout voltage (between OUT pin and GND pin) needed for the expecting current. If 50V ~ 100V voltage level is adopted as power source to positive end of the LED string, one Zener shunt regulator could be used to provide appropriate voltage (lower than 50V) to VDD pin. The supply voltage to VDD pin and LED+ end could also be separated. Note that, heat-sink area on PCB is required if the dropout voltage between OUT pin and GND pin is too large. Please refer to the "Thermal Consideration" section. Liteon Semiconductor Corp. 6/6 20090720_1.0 LSP7706 1.1A High Voltage Adjustable Current Regulator 4. Application for LED Lighting LSP7706 could coordinate with any type of DC-to-DC converter through feedback path to realize LED lighting module. The number of LEDs in the string is variable even with certain fixed power source since the output voltage of the DC-to-DC converter could be modulated according to feedback signal. In the following figure, DFB is used to feed the dropout voltage of OUT pin of the LSP7706 back to DC/DC converter; and RFB is the pull-high resistor for DFB. 5. AC Voltage Input LSP7706 could work with any kind of well-developed switch-mode power supply system. Simply cut off the internal feedback path of the power supply system and then feed the signal from LSP7706 back to the power supply system instead. Liteon Semiconductor Corp. 7/7 20090720_1.0 LSP7706 1.1A High Voltage Adjustable Current Regulator 6. Output Capacitor CO If the LED string and LSP7706 is located in separate PCBs, or the length of the routing path L1>10cm or L2>3cm, the output capacitor CO should be added. Typically, capacitance of 0.1uF ~ 1uF is recommended and 1uF is needed when L2 is much longer than 3cm. The output capacitor CO may be neglected under certain condition. If the LED string and LSP7706 are located in the same PCB, and the length of the routing path L1<10cm & L2<3cm, the output capacitor CO can be neglected. Liteon Semiconductor Corp. 8/8 20090720_1.0 LSP7706 1.1A High Voltage Adjustable Current Regulator THERMAL IMPEDIENCE The Maximum Power Dissipation on Current Regulator PD(MAX) = VOUT(MAX) x IOUT(NOM) + VIN(MAX) x IDD VOUT(MAX) = the maximum voltage on output pin; IOUT(NOM) = the nominal output current; IDD = the quiescent current the regulator consumes at IOUT(NOM); VIN(MAX) = the maximum input voltage. Thermal Consideration The LSP7706 has internal power and thermal limiting circuitry designed to protect the device under overload conditions. However, maximum junction temperature ratings should not be exceeded under continuous normal load conditions. The thermal protection circuit of LSP7706 prevents the device from damage due to excessive power dissipation. When the device junction temperature rises to approximately 160C, the regulator will be turned off. When power consumption is over about 1.22W (TO-263 and TO-220 package, at TA=70C), additional heat sink is required to control the junction temperature below 125C. The junction temperature is: TJ = PD (JT +TS +SA ) + TA PD : Dissipated power. JT: Thermal resistance from the junction to the mounting tab of the package. For TO-263 package, JT = 3.0 oC /W. TS: Thermal resistance through the interface between the IC and the surface on which it is mounted. (typically, TS < 1.0C /W) SA: Thermal resistance from the mounting surface to ambient (thermal resistance of the heat sink). If PC Board copper is going to be used as a heat sink, below table can be used to determine the appropriate size of copper foil required. For multi-layered PCB, these layers can also be used as a heat sink. They can be connected with several through-hole vias. PCB SA (C /W) 2 PCB heat sink size (mm ) 59 45 38 33 27 24 21 500 1000 1500 2000 3000 4000 5000 Recommended figure of PCB area used as a heat sink. Thermal-pad of TO-263 Through hole vias Liteon Semiconductor Corp. 5 OUT 4 OE 3 GND 2 ISET 1 VDD 9/9 20090720_1.0 LSP7706 1.1A High Voltage Adjustable Current Regulator ORDERING INFORMATION LSP7706X X X X Package: D: TO252 K: TO263 T: TO220 Output Voltage: Blank: Adj Packing: A: Tape & Real Temperature Grade: d: -4085 MARKING INFORMATION TO263-5L Liteon Semiconductor Corp. TO252-5L 10/10 20090720_1.0 LSP7706 1.1A High Voltage Adjustable Current Regulator PACKAGE INFORMATION 5-Pin Surface Mount TO-263 INCHES C A D I B K N M L E F G MILLIMETERS MIN TYP MAX MIN TYP MAX A 0.395 - 0.420 10.03 - 10.67 B 0.325 - 0.361 8.25 - 9.17 C 0.171 - 0.181 4.34 - 4.59 D 0.045 - 0.055 1.14 - 1.40 E 0.013 - 0.017 0.330 - 0.432 F 0.029 - 0.035 0.737 - 0.889 G 0.062 - 0.072 1.57 - 1.83 I - - 0.065 - - 1.65 K 0.575 0.635 14.60 16.13 L 0.090 0.110 2.29 2.79 M 7 7 N 3 3 5-Pin Plastic TO-220 S B INCHES C T F A K G N D Liteon Semiconductor Corp. MIN TYP A 0.560 - B 0.380 C TYP MAX 0.650 14.23 - 16.51 - 0.420 9.66 - 10.66 0.140 - 0.190 3.56 - 4.82 D 0.018 - 0.035 0.46 - 0.89 F 0.140 - 0.160 3.56 - 4.06 G 0.134 - - 3.40 - - J 0.012 - 0.045 0.31 - 1.14 K 0.500 - 0.580 12.70 - 14.73 N R J 11/11 MILLIMETERS MAX MIN 0.268 TYP 6.80 TYP R 0.080 - 0.115 2.04 - 2.92 S 0.045 - 0.055 1.14 - 1.39 T 0.230 - 0.270 5.85 - 6.85 20090720_1.0 LSP7706 1.1A High Voltage Adjustable Current Regulator TO-252-5L Symbol A A1 B C c1 D D1 E E e1 L1 L2 L3 V Dimensions in Millimeters MIN 2.200 0.000 0.400 0.430 0.430 6.350 5.200 5.400 Dimensions in Inches MAX 2.400 0.127 0.600 0.580 0.580 6.650 5.400 5.700 MIN 0.087 0.000 0.016 0.017 0.017 0.250 0.205 0.213 1.270 TYP 2.540 TYP 9.500 1.400 2.550 MAX 0.094 0.005 0.024 0.023 0.023 0.262 0.213 0.224 0.050 TYP 1.000 TYP 9.900 1.780 2.900 0.374 0.055 0.100 3.800 REF 0.390 0.070 0.114 0.150 REF UPDATE HISTORY Date Version Description July 20, 2009 1.0 New generation Liteon Semiconductor Corp. 12/12 20090720_1.0