BL8582 Single-Wire Dimming, 3-Channels WLED Linear Drive DESCRIPTION FEATURES The BL8582 is a CMOS based White/Blue LED driver with stand-alone capability. The driver is primarily designed for LED backlighting of LCD display powered by Li-ion battery With its high efficiency, low standby current and wide range of input supply voltage, the BL8582 is suitable for applications such as portable device display and keypad backlighting. It can realize dimming control through EN pin. Inner the device, there is a 4-bit counter, so the LED current can be set at 16 levels with 1/15 Imax step. BL8582 has three LED channels with a SOT-23-6 package. • • • • • • • APPLICATIONS • • TYPICAL APPLICATION www.belling.com.cn 2.7 to 5.5V input range Single-wire dimming control with linear 16-steps. PWM dimming control LED sink current of max. 20mA Independent current sink circuit for each LED output Low standby current High accuracy current match on each channel 1 Small Size Color LCD Backlights Driver Mobile Phone, Portable DeviEN Keypad Backlights Driver BL8582 ORDERING INFORMATION PIN CONFIGURATION BL8582 □ 1 □ 2 □ 3 Code Description Temperature&Rohs: 1 C: -40~85°C, Pb Free Rohs □ Std. Package type: 2 □ B6: SOT-23-6 Packing type: 3 □ TR:Tape&Reel (Standard) Product Classification BL8582CB6TR Marking 82: Product Code 82ZZ ZZ: Date Code PIN DESCRIPTION Name LED1-LED3 Function Description RGB or WLED cathode connection pin EN Chip enable and dimming control. VCC Power Supply GND Ground. ABSOLUTE MAXIMUM RATING Supply voltage –0.3V to 7V Voltage of LEDn, EN pin –0.3V to 7V Maximum Junction Temperature 125°C Operating Ambient Temperature Range –40°C to 85°C Storage Temperature Range –40°C to 150°C Lead Temperature (Soldering, 10 sec) 260°C Note: Exceed these limits to damage to the device. Note: Exposure to absolute maximum rating conditions may affect device reliability. RECOMMENDED OPERATING CONDITIONS Items Supply Voltage Range Output sink current on each channel Operating Temperature www.belling.com.cn MIN 2.7 NOM -25 2 MAX 5.5 25 85 Unit V mA ℃ BL8582 BLOCK DIAGRAM VCC LED1 LED1 LED3 LED3 LED2 LED2 Enable & Logic EN Shunt Regulator GND ELECTRICAL CHARACTERISTICS VCC=3.7V, Ta=25°C, No Load, Input: VEN=3.7V. (Unless otherwise noted) Symbols Parameters VIL VIH IIL IIH TD EN Pin “Low” Logic EN Pin “High” Logic 1.7 V V EN Pin “Low” Input Current -1 µA TLAT TPULSE VLEDL ILED ∆ILEDn IQ ISTBY Conditions MIN TYP MAX Unit 0.4 EN Pin “High” Input Current 1 PWM dimming control delay time Latch off time before transient to the new current level (see figure 2) 18 µS 20 µS Quiescent Current 100 20 250 Standby Supply Current VEN=”0” 3 22 µS mV mA 3 % 400 µA 20 -3 LEDn Sink Current Deviation www.belling.com.cn 20 EN dimming control 4 The positive and negative width LEDn Dropout Voltage LEDn Sink Current µA 0.5 µA BL8582 DETAILED DESCRIPTION BL8582 works with a wide range of supply voltage, from 2.7V to 5.5V. The forward voltage of commercial white/blue LED is in the range of 2.9V to 3.5V at a current level of 20mA. Proper selection of the LED to match the supply voltage can fully utilize the Li-ion battery. For example, there is 1% ~ 3 % power left in the Li-ion battery when its voltage reaches 3.275V. So a LED with a forward voltage value of 3.2V can use up to 99% of the battery power under normal working condition. When the voltage of the battery drops below 3.2V, the current through the LED (hence the brightness) starts to decrease. pulse width wider than 20uS is regarded as a signal to stop the build-in counter. The time between two wide high levels (more than 20uS) is a counting period. When some rise edges occur between two high level pulses of 20us, the equation as shown below can calculate the active pulse number, called Code_No. Code _ No = Mod ( N ,16) , In the equation, N is the number of rise edges of the input waveform and mod function returns the remainder of N divided by 16. For example, if N=0, 16, or other integral multiple of 16, the mod function returns a value of 0, if N=1, 17 or other integral multiple of 16 plus 1, the mod function returns a value of 1, and so on. Startup sequence BL8582 starts to work only when VCC powered on and the EN pin became high after a delay, the delay time is at least 4us. EN pin is not allowed to connect to VCC directly or keep it floating. The relationship between LEDs’ brightness and the Code_No is listed as the following table. PWM dimming control Code No 0 1 2 3 4 5 6 7 If the frequency of the PWM signal to the EN pin is less than 5KHz, the average LED current is proportional to the duty cycle of the PWM signal, and the EN works as a simple on/off control. A high level turns on and a low shuts down the LEDs. There is a delay time between the input PWM signal and the output LED current waveform, as shown in Fig.1, the TD is about 20uS. ON duty ISET/20mA 0 1 14/15 13/15 12/15 11/15 10/15 9/15 Code No 8 9 10 11 12 13 14 15 ISET/20mA 8/15 7/15 6/15 5/15 4/15 3/15 2/15 1/15 The frequency of the input pulse should be lower than 100KHz, and the width of the high level and low level larger than 4uS to prevent false trigger. EN Td=20uS Td=20uS 20mA Code_No=1 I_LED Code_No=4 Fig. 1 PWM Dimming Control EN dimming control EN The LEDs’ brightness can also be controlled by the pulses applied to the EN pin, Refer to the Fig. 2. Inside the device there is a 4-bit counter connecting to the EN pin. The LED current can be programmed up to 16 levels depends on the number of rise edges of the input waveform. A high level input (“1”) with www.belling.com.cn I_LE D 20uS 20uS Iset/20mA=15/15 Iset/20mA=12/15 Fig. 2 Linear current Dimming Control 4 BL8582 TYPICAL PERFORMANEN CHARACTERISTICS Quiescent Current vs Temperature (VCC=3.7V) 350 450 300 400 Quiescent Current (uA) Quiescent Current (uA) Quiescent Current vs Supply Current (Ta=25℃) 250 200 150 100 50 0 3.0 350 300 250 200 150 100 50 0 3.5 4.0 4.5 5.0 -40 -20 0 Supply Voltage (V) 40 60 80 100 120 140 Temperature (℃) ILED vs Supply Voltage ILED vs LEDn Dropout Voltage (VCC=3.7V) (VCC=3.7V, VLEDn=3.2V) 22 25 20 20 LED Current (mA) ILED (mA) 20 18 16 14 15 10 12 5 10 3.3 3.4 3.5 3.6 3.7 3.8 3.9 4.0 4.1 4.2 0 0.01 0.1 Supply Voltage (V) 1 10 LEDn Dropout Voltage (V) LED Current VS Code_No ILED vs Temperature (VCC=3.7V) 16 LED Current(mA) ILED (mA) 20 20.2 20.2 20.1 20.1 20.0 20.0 19.9 19.9 19.8 19.8 19.7 12 8 4 0 -50 -25 0 25 50 75 100 0 125 4 6 8 Code_No Temperature (℃) www.belling.com.cn 2 5 10 12 14 16 BL8582 PACKAGE LINE Package SOT-23-6 Devices per reel Package dimension： www.belling.com.cn 6 3000Pcs Unit mm