FAN5645

FAN5645 — Indicator LED Blinker with Single-Wire Interface September 2007 FAN5645 Indicator LED Blinker with Single-Wire Interface Features Records and plays back blink patterns Single-wire digital control of LED blink rate and intensity Resistor-programmable LED maximum current High-side constant-current driver topology: Description The FAN5645 is a flexible and compact solution for a blinking LED indicator. The internal programmable blink algorithm eliminates any need for continual system processor control. This means longer battery life for the hand-held system because the system processor is not awakened from sleep mode just to blink an LED. Very low dropout of 40mV allows driving an LED without any inductors or switch capacitors. An external resistor sets the LED output current level. LED blink rate and intensity is controlled by a simple one-wire interface. In shutdown mode, the supply current is reduced to 0.3µA (typical). The FAN5645 is available in 6-pin molded leadless package (MLP). - 20mA maximum output 40mV typical dropout at 20mA 33µA operating current Standard 1.8V logic Short-circuit protection Thermal Shutdown Protection Under-Voltage Lockout Protection 6-pin 3.0 x 3.0mm MLP package Applications Cell Phones, Smart-Phones Pocket PCs, Bluetooth Headsets PDA, DSC, PMP, and MP3 Players Laptop Computers ® Typical Application 2.7 to 5.5V VBAT C IN 0.1µF VIN GND CTRL LED+ ISET GND R SET Control Figure 1. Typical Application for the FAN5645 Ordering Information Part Number FAN5645MPX Package MLP-6 3.0 x 3.0mm Pb-Free Operating Temperature Range Packing Method -40°C to 85°C Tape and Reel Bluetooth® is a registered trademark of Motorola, Inc. © 2006 Fairchild Semiconductor Corporation FAN5645 • Rev. 1.0.0 www.fairchildsemi.com FAN5645 — Indicator LED Blinker with Single-Wire Interface Block Diagram Under-Voltage UVLO Lockout Thermal Shutdown Protection TSD CTRL Input edge detector & timer Oscillator DATA Control logic & memory LED ON Bandgap reference Ref. current generator Output current mirror LED+ VIN GND ISET RSET Figure 2. Block Diagram Pin Configuration GND LED+ 1 6 VIN GND 2 P1 (GND) 5 ISET 3 4 CTRL Top View Figure 3. MLP Pin Assignments Pin Definitions Pin # 1 2 3 4 5 6 Name GND LED+ ISET CTRL GND VIN Description Ground. 0V reference for all voltages. LED output. Connect to anode of LED. Current Set. Resistor to GND sets maximum LED current 1:400. Digital single wire interface. Program STOP/TRAIN/RUN sequences. Ground. 0V reference for all voltages. Power input. www.fairchildsemi.com 2 © 2006 Fairchild Semiconductor Corporation FAN5645 • Rev. 1.0.0 FAN5645 — Indicator LED Blinker with Single-Wire Interface Absolute Maximum Ratings Stresses exceeding the absolute maximum ratings may damage the device. The device may not function or be operable above the recommended operating conditions and stressing the parts to these levels is not recommended. In addition, extended exposure to stresses above the recommended operating conditions may affect device reliability. The absolute maximum ratings are stress ratings only. Symbol ISET Voltage TJ TSTG TL ESD Junction Temperature Storage Temperature Parameter VIN, LED+, CTRL Voltage Min. -0.3 -0.3 -40 -65 HBM 7 2 8 Max. +6.0 VIN+0.2 150 150 260 Unit V V °C °C °C kV Lead Soldering Temperature, 10 seconds Electrostatic Discharge Protection Level CDM HBM (on LED+ pin) Recommended Operating Conditions The Recommended Operating Conditions table defines the conditions for actual device operation. Recommended operating conditions are specified to ensure optimal performance to the datasheet specifications. Fairchild does not recommend exceeding them or designing to absolute maximum ratings. Symbol VIN IOUT RSET TA TJ Output Current Parameter Power Supply Voltage Range Resistor Used to Set LED Current Operating Ambient Temperature Range Operating Junction Temperature Range Min. 2.7 1 24.7 -40 -40 Max. 5.5 20 494.0 +85 +125 Units V mA kΩ °C °C © 2006 Fairchild Semiconductor Corporation FAN5645 • Rev. 1.0.0 www.fairchildsemi.com 3 FAN5645 — Indicator LED Blinker with Single-Wire Interface Electrical Specifications VIN = 2.7V to 5.5V, TA = -40°C to +85°C, Vf = 1.8V to (3.5V or VIN-0.1V, whichever is smaller). Typical values are at TA = 25°C, VIN = 3.6V, and Vf = 2.5V. Symbol Parameter Conditions VIN = 3.6V VIN = 3.6V, ILED = 0mA Min. Typ. 0.30 33 Max. 0.75 55 Units µA µA V Power Supplies Shutdown current in STOP ISD (sleep) mode IIN VIH VIL IIH VUVLO Regulation IOUT Maximum regulated output current Minimum regulated output current Maximum LED ripple current ISET accuracy IOUT load regulation IOUT line regulation ISET voltage ISET current limit Current mirror ratio VDROPOUT ISC TSD Timing fOSC TOSC tON tOFF Internal oscillator frequency Oscillator stability LED on-time resolution LED off-time resolution (1) (1) (1) Operating current in RUN,TRAINING, RUN_ONCE, RESET_FOLLOW modes Control high-level input voltage Control low-level input voltage Control pin input current Under-voltage lockout threshold 1.2 0.4 CTRL = 1.8V VIN Rising VIN Falling 1 2.5 2.2 100 V nA V V Sourced from LED+ pin Sourced from LED+ pin ΔVIN = 700mV, trise = tfall = 10µs, T = 570µs TA = 25°C, ILED = 1mA-20mA ILED = 1mA-20mA LED Vf = 1.8 to 3.5V, VIN = 3.6V VIN = 2.7 to 4.8V, Vf = 2.5V 24kΩ ≤ RSET ≤ 494kΩ VLED+ = 0V, VISET = 0V IOUT / ISET ILED = 20mA, -10% drop RSET or IOUT w.r.t GND Rising Temperature at Junction Hysteresis VIN = 3.6V 20 mA 1 0.5 -3 5 -3 -3 1.235 150 400 40 60 150 20 51 -3 1 10 64 77 3 80 mV mA °C °C kHz % ms ms +3 +3 +3 % p-p % % % % V μA IOUT_RIPPLE ∆ISET ∆IOUT_LOAD ∆IOUT_LINE VISET ISET_LIM ISET_LINEARITY ISET linearity Dropout voltage Short-circuit current limit Thermal shutdown Note: 1. Guaranteed by design; not tested in production. © 2006 Fairchild Semiconductor Corporation FAN5645 • Rev. 1.0.0 www.fairchildsemi.com 4 FAN5645 — Indicator LED Blinker with Single-Wire Interface Circuit Description Operational Modes At power up, the device is in STOP (“SLEEP”) mode until a rising edge of a CTRL signal is detected and the device goes into active mode. Depending upon the signal applied to CTRL, active mode can be TRAINING, RUN, RUN ONCE, or FOLLOW AFTER RESET. Initialization The reference and the circuit remain in SLEEP mode until VIN crosses the UVLO threshold and a rising edge on the CTRL pin is detected. When the IC is in SLEEP mode, all internal bias circuits are disabled. The training registers are all reset to 0 at power up. Training Mode The IC can record a pattern of up to three distinct HIGH (TON) and LOW (TOFF) times. These times are recorded during training in six internal 8-bit counters, one counter for each distinct TON and TOFF time. If the training pulse ON or OFF time exceeds the maximum clock counts, the value is held at the maximum. TRAINING mode contains the following sequence: TFTPR TCMD1 TCPHIGH T CMD2 1. Two control pulses, finished within TCMD1. The HIGH time of the control pulses should be greater than 2µs and less than 55µs. The LOW time between two control pulses should be greater than 2µs. 2. CTRL held LOW, for at least TFTPR(MIN), but less than TFTPR(MAX), measured from the first rising edge of the control pulse. 3. Between one and three sets of training pulses, where a training pulse defines the LED’s on time TON and off-time TOFF. 4. Three control pulses finished within TCMD2 to signify end of training. The HIGH time of the control pulses should be greater than 2µs and less than 55µs. The LOW time between two control pulses should be greater than 2µs. 5. The IC enters STOP (SLEEP) mode and is able to receive a new command only after TCMD2 expires. 6. If no end-of-training controls pulses are received after TOFF3 maximizes out, the IC enters STOP (SLEEP) mode automatically. CTRL TCPLOW TON1 TOFF1 TON2 TOFF2 TON3 TOFF3 Figure 4. TRAINING Mode RUN Mode W hen CTRL is raised and held HIGH, and training registers are not all zeros, repetitive playback of the trained sequence commences. The delay between CTRL HIGH and LED on is TDLY1. When CTRL T DLY subsequently goes LOW, the IC turns off the LED and enters STOP (SLEEP) mode. After a TCMD2 time, a new command can be processed. CTRL Trained Sequence LED TON1 Figure 5. RUN Mode Run Once Mode W hen the IC receives four consecutive control pulses within TCMD1, followed by CTRL going HIGH after at least TFTPR(MIN), but less than TFTPR(MAX), the IC plays TFTPR TCMD1 TCPHIGH CTRL TCPLOW LED TON1 Trained Sequence back the trained pattern once, then enters STOP (SLEEP) mode after the trained sequence is completed. This assumes that training registers are not all zeros. Figure 6. RUN ONCE Mode © 2006 Fairchild Semiconductor Corporation FAN5645 • Rev. 1.0.0 www.fairchildsemi.com 5 FAN5645 — Indicator LED Blinker with Single-Wire Interface RESET and FOLLOW Modes Reset mode consists of two control pulses, then CTRL goes LOW for longer than TTIMEOUT. The IC clears all training registers to zero, then enters STOP (SLEEP) mode. TTIMEOUT TCPHIGH CTRL TCPLOW set of control pulses. When the CTRL signal goes LOW, LED current is turned off and the IC enters STOP (SLEEP) mode. A TCMD2 waiting period, after the last trailing edge of the CTRL input, is necessary before a new command can be received and processed. Note that FOLLOW mode can be entered upon power up as well, because all registers are cleared on power up and the device acts as if in RESET mode. CTRL TDLY LED Figure 7. RESET Mode After the IC goes through RESET mode; if CTRL goes HIGH again for longer than TDLY, the IC begins Follow mode, which causes the LED to be turned ON when CTRL is HIGH. The IC delays turning on the LED after the rising edge of CTRL by TDLY to determine whether the CTRL rising edge is to be interpreted as a command to turn the LED ON or the beginning of a new Figure 8. FOLLOW Mode Timing Symbol TCMD1 TFTPR TCMD2 TTIMEOUT TDLY TCPHIGH TCPLOW TON1 TOFF1 TRESTART Description Maximum time window in which starting control pulses must be finished Time window from first control pulse rising edge to first rising edge of training pulse Maximum time window in which ending control pulses must be finished Minimum time window CTRL line has to stay LOW after control pulses to enter and finish RESET mode (starting from the first rising edge of the control pulse) Time delay in playback or follow mode b/t rising edge of CTRL line to when LED turns ON for the first time Control pulse HIGH width Control pulse LOW width LED ON time in Run modes LED OFF time in Run modes Over-temperature or over-current fault time in Follow mode Min. Typ. Max. 0.8 Units ms ms ms ms 1.5 1.7 0.85 4.0 0.95 2 2 1.0 10 10 255.0 2550 1.10 1.45 55 ms μs μs ms ms ms Over-Current, Over-Temperature, and Under-Voltage Faults An over-current fault occurs if the ISET pin is shorted to GND or the RSET resistor value is too low. If the resulting LED current is greater than three times the maximum programmed output current (60mA), the IC shuts down its output current and disables the reference voltage developed on the ISET pin. An over-temperature fault occurs when the IC exceeds 150°C, which also causes the IC to shut down its output current and disable the reference voltage developed on the ISET pin until the IC cools by about 20°C. If either fault occurs, the IC turns off the output LED current and disables the reference voltage developed © 2006 Fairchild Semiconductor Corporation FAN5645 • Rev. 1.0.0 www.fairchildsemi.com 6 on the ISET pin. If a short-circuit or over-temperature fault occurs during playback modes, playback is retried when the next playback pulse (TON) comes. If a shortcircuit or over-temperature fault occurs during Follow mode, the LED turns off for TRESTART, then Follow mode tries to resume the LED current according to the current state of the CTRL line. If an under-voltage fault occurs, the IC turns off the LED and enters SLEEP mode until the next control pulse comes, at which point the IC tries to wake up. FAN5645 — Indicator LED Blinker with Single-Wire Interface Application Information Setting the LED Current The LED forward current is established by the external resistor, RSET, according to: ILED = 400 • 1.235V / RSET where 1.235V = Typical ISET voltage, and 400 = Typical current mirror ratio. EQ.1 Selecting External Components A ceramic capacitor of 0.1µF or more can be added between VIN and GND to reduce the electrical noise at the power supply line. The minimum value of VIN should exceed Vf by as little as 40mV to ensure the LED current is regulated at the right value. Conversely, the LED should be selected to have the Vf at the specified current, at least 40mV lower than the minimum VIN. The LEDs utilized as blinking indicators, driven by the FAN5645, may be white or any color. The forward current voltage characteristics and the absolute maximum ratings are provided by the manufacturer in their technical specifications. The typical forward voltage at 15mA current is 1.9V for red and orange, 2V for yellow, 2.1V for green, and 3.3V for bright white, bright non-yellowish green, and most blue types. Meet the maximum rated current of the LED only under favorable conditions with little or no heat buildup. Some LED current ratings assume really favorable test conditions - such as surrounded by air no warmer than 25°C and decent thermal conduction from where the leads are mounted. Running LEDs at specified laboratory conditions used for maximum current rating can cause LEDs to lose half the light output after rated life expectancy (20,000 to 100,000 hours), best-case. The ILED accuracy is determined by the tolerance of the above parameters over the input voltage and the ambient temperature range as well the tolerance of the RSET resistance. For best accuracy, RSET should be a precision resistor, connected close to the IC pins, so that the voltage across RSET is identical to the voltage between the ISET and GND pins. Programming the LED ON times below 20 - 30ms appears as a flash, rather than as a blink with an observable ON time, to the observer. The brightness of such a flash is determined by the energy delivered during the flash. It is possible to change the apparent brightness by varying the ON / OFF time ratio, keeping the frequency higher than 40Hz. Since the resolution of the ON time is in 1ms increments, a dimming function for 20 discrete levels of brightness can be implemented via software. © 2006 Fairchild Semiconductor Corporation FAN5645 • Rev. 1.0.0 www.fairchildsemi.com 7 FAN5645 — Indicator LED Blinker with Single-Wire Interface Typical Performance Characteristics Unless otherwise noted, VIN = VEN = 3.6V, TA = 25°C, white LED with Vf = 3.3V at ILED = 20mA. 20.20 20.15 V f=2.1V 25 -40°C LED Current (mA) 20.05 20.00 19.95 19.90 19.85 19.80 2.5 3.0 3.5 4.0 4.5 5.0 5.5 LED Current (mA) 20.10 20 -40°C +25°C +85°C 15 10 5 0 0 +25°C +85°C 0.01 0.02 0.03 0.04 0.05 0.06 0.07 0.08 0.09 0.10 VIN(V) VIN(V)-VOUT(V) Figure 9. Line Regulation Figure 10. LED Current vs. Headroom Voltage 22 20 18 430 425 420 -40°C Current Mirror Ratio 16 ILED (mA) 14 12 10 8 6 4 2 0 10 100 1000 415 410 405 400 395 390 385 0 2 +25°C +85°C 4 6 8 10 12 14 16 18 20 RSET(k ) LED Current (mA) Figure 11. LED Current vs. RSET Resistance Figure 12. Current Mirror Ratio vs. Output Current Vf=2.5V VCTRL=1.2V VIN=3.7V VIN=3.0V VCTRL=0.4V ILED=20mA ILED(AC), 0.1mA/div. on top of 20mA ILED=0mA Horizontal Scale: 20µs/div. Horizontal Scale: 500µs/div. Figure 13. Line Transient Response Figure 14. Active Modes Delay © 2006 Fairchild Semiconductor Corporation FAN5645 • Rev. 1.0.0 www.fairchildsemi.com 8 FAN5645 — Indicator LED Blinker with Single-Wire Interface Physical Dimensions Figure 15. 6-Pin Molded Leadless Package © 2006 Fairchild Semiconductor Corporation FAN5645 • Rev. 1.0.0 www.fairchildsemi.com 9 FAN5645 — Indicator LED Blinker with Single-Wire Interface © 2006 Fairchild Semiconductor Corporation FAN5645 • Rev. 1.0.0 www.fairchildsemi.com 10