［AP2152］ AP2152 3CH High Power WLED Driver DESCRIPTION The AP2152 is a 3 channel white LED driver IC. It is composed of a current mode DC/DC boost converter with an internal power MOSFET and 3 channel constant current sources, which can drive up to 10 LEDs per channel for a maximum of 30 LEDs. The AP2152 achieves ±0.8% typ. LED current matching between each channel when the LED current is set at 75.8mA. The LED current can be run up to a maximum of 120mA with the appropriate external set resistor on the ISET pin. The AP2152 operates over a wide input voltage range from 4.25V to 35V, and the switching frequency goes up to a maximum of 2.5MHz with the appropriate external set resistor on the RT pin. The switching frequency can also be synchronized with an external signal. The AP2152 provides the LED dimming function via an external PWM signal, with a frequency range from 100Hz to 20KHz. The AP2152 provides LED open protection, LED short protection, OVP pin short protection, channel short protection, over voltage protection, over current protection, thermal protection and UVLO. FEATURES White LED driving number: Maximum 30 pieces (10 pieces in series x 3 in parallel) LED current matching: ±0.8% typ. (ILED=75.8mA) LED maximum current: 120mA Maximum switching frequency: 2.5MHz PWM dimming frequency by applying external signal: Maximum 20kHz Input voltage range: 4.25V∼ ∼35V Built-in 45V power MOSFET Error flag through serial interface Synchronize with External frequency Master – Slave configuration LED open protection LED short protection OVP pin short protection Output channel short protection Overvoltage protection (OVP) Over current protection Thermal protection UVLO 20 pin HTSSOP with heat-sink package APPLICATIONS MS1348-E-00 Display backlight Lighting equipment 1 2012/05 ［AP2152］ BLOCK DIAGRAM VIN CH1 CH2 CH3 VOUT COUT ROVP2 ROVP1 COMP LX 1 OVP 11 10 CURRENT SENSE THERMAL SHUTDOWN TSD ERROR AMP VOLTAGE SELECT CS PGND 3 SS 2 CH1 3 + - DRI VER 19 ∑ LED S HORT PROTECTI ON CH2 SW ITCH LOGIC 18 PWM PGOOD OVE R VOLTAGE P ROTECTI ON CS VOSP 15 VDC TIMER LA TCH 14 CH3 17 3 PWM VOUT SHORT PROT ECTION TM LOW SIDE CURRENT S INK CH OPEN PROTECTI ON VOSP PWM COMPARATOR LE D TIMER VDC ERROR AMP OS C SS TSD CS VOSP VIN VDC CH SHORT 3 UVLO CURRENT SINK LDO DIMMI NG CONT ROL 8 5.0V TIMER 9 REG Fail CH SCLK 4 TIMER LATCH 4bit SERIA L I/F SDATA 3 3.0V 6 7 12 SYNC CLKO 5 RT 13 PWM 20 ISET GND Figure 1. AP2152 Block Diagram MS1348-E-00 2 2012/05 ［AP2152］ PIN LAYOUT and APPLICATION CIRCUIT EXAMPLE TOP VIEW VOUT LX 1 20 GND PGND CH1 SDATA CH2 SCLK CH3 PWM SYNC HTSSOP20 VIN L CIN1 R OVP2- 1 COUT 1 COUT2 R OVP2- 2 RCOMP CCOM P 1 CC OMP 2 1 NC 2 ROVP1 11 10 OVP COMP LX PGN D CH1 19 CH2 18 CH3 17 PGOOD 15 CLKO D PGOOD TM VIN ISET VDC RT 14 TM 8 VIN CT M SCLK 4 OVP 10 11 COMP CIN2 SDATA 9 C VDC VDC SYNC PWM GN D RT ISET 6 5 20 12 13 4 3 CLKO RT RISET RSY NC PWM INPUT Figure 2. AP2152 Pin Layout and a circuit example PIN DESCRIPTION Pin No. Pin Name 1 LX 2 PGND 3 SDATA 4 SCLK 5 PWM 6 SYNC 7 CLKO 8 VIN 9 VDC 10 OVP 11 COMP MS1348-E-00 Function Power MOSFET pin. Nch MOSFET open-drain. If 2.6A or higher current is detected on this pin, over-current protection circuit is activated. GND for power MOSFET Data output from serial interface. Nch open-drain output. The output data will be synchronized with the clock input on the SCLK pin.. When the data function is unnecessary please connect to GND. Clock input for serial interface. When the clock function is unnecessary please connect to GND. PWM dimming signal input pin. Built-in 200kΩ pull down resistor. This also functions as the enable input, and if this pin goes to a high level, the IC is changed from the stand-by state to the enable state, the internal LDO is activated, and the boost operation begins. If this pin goes to a low level, the internal timer starts counting, 30msec later the IC goes into the standby state. Clock input pin for synchronous operation. Built-in 1MΩ pull-down resistor. If the synchronous operation is unnecessary, please connect to GND. Internal clock output pin. If the clock function is unnecessary, please keep this pin open. Power input pin. Internal LDO input to provide power for internal circuits. 1.0μF should be connected between the VIN pin and GND. Internal LDO output pin. 5V output by regulating from VIN. Maximum output current is 30mA. 1.0μF should be connected between the VDC pin and GND. Over voltage protection detection circuit input pin. The voltage at the OVP pin is the LED Anode voltage divided by the resistor divider. If the voltage exceeds 1.2V, the boosted LED anode voltage will be suppressed. If the voltage goes below 0.1V, the OVP pin short protection circuit is activated. DC/DC boost converter phase compensation pin. A resistor and a capacitor should be connected between the COMP pin and GND. 3 2012/05 ［AP2152］ Pin No. Pin Name 12 RT 13 ISET 14 TM 15 PGOOD 16 NC 17 CH3 18 CH2 19 CH1 20 GND THERMAL PAD - Function Switching frequency set pin. Oscillation frequency can be set by connecting a resistor between the RT pin and GND. Please refer to section 2.4 “Switching frequency setting/Function of synchronizing with external clock”. LED driving current set pin. LED current can be set by connecting a resistor between the ISET pin and GND. Please refer to section 2.3 “LED current setting”. Capacitor connection pin for timer. If an abnormality occurs in the IC, this pin outputs 10µA constant current. If this pin voltage exceeds 2.0V, the IC ceases its operation. By returning to the standby state, the timer is reset and the IC can be released. When the timer is unnecessary, please connect to GND. Please refer to section 2.6 “Timer latch (TM) setting”. Power Good pin. N channel open-drain, it keeps OFF when normal operation. If an abnormality occurs in the IC, the operation is latched off by timer latch function and internal FET turns ON. Please refer to “Protections description” for the detail of Power Good pin status described later. When the power good function is unnecessary, please connect to GND. NC pin. WLEDs constant current circuit 3. CH3 is open drain, and provides constant current to the LEDs. If this constant current channel is unnecessary, please keep this pin open. WLEDs constant current circuit 2. CH2 is open drain, and provides constant current to LEDs. If this constant current channel is unnecessary, please keep this pin open. WLEDs constant current circuit 1. CH1 is open drain, and provides constant current to LEDs. If this constant current channel is unnecessary, please keep this pin open. GND pin for internal circuits. For heat radiation, connection to GND is recommended. This is electrically isolated from the internal circuit. ABSOLUTE MAXIMUM RATINGS Rating VIN voltage LX, CH1-3 Voltage Symbol VIN VLX, VCH Value -0.3 to +45 Unit V *1 Condition -0.3 to +45 V *1 SDATA, SCLK, PWM,VDC, -0.3 to +6 V *1 PGOOD, SYNC voltage OVP, COMP, RT, -0.3 to (VDC + 0.3) V *1*4 ISET, TM, CLKO voltage CH1-3 current ICH 140 mA PGOOD current IGOOD 20 mA Power Dissipation PD 2500 mW *2, *3 Operating Temperature Range TOP -40 ~ +105 °C Storage Temperature Range TSTG -55 ~ +150 °C Note: *1. All voltages refer to GND pin (GND, PGND) as zero (reference) voltage. *2. PD must be decreased at the rate of 23.3mW/°C for operation above 25°C. *3. Mounted on a 50 mm × 50 mm x 1 mm double sided FR-4 board. *4. The maximum value is limited to 6.0V if VDC exceeds 5.7V. Note：The maximum ratings are the absolute limitation values with the possibility of damage/breakage. When operation exceeds this standard, quality cannot be guaranteed. MS1348-E-00 4 2012/05 ［AP2152］ ELECTRICAL CHARACTERISTICS VIN=12V, GND=PGND=0V, RISET=36kΩ, RT=91kΩ, PWM=5V, TA=+25°C unless otherwise specified. Items marked by● are guaranteed by design in the range of -30℃ to +85℃. Parameter DC/DC Converter Input voltage Range Supply Current(SW ON) Standby Current UVLO Voltage UVLO Hysteresis Width Switching Frequency Symbol VIN IDD ISTB VUVLO MIN ● VHYS_UVLO FOSC ● LX On Resistance LX Off Leak Current Maximum On Duty LX Minimum On Time COMP Output High Voltage COMP Output Low Voltage Error Amp Reference Voltage 4.25 3.75 ● RLX ILEAK_LX DMAX TLX_MIN VOH_COMP VOL_COMP VREF_EA Current Sink Circuit and Dimming Part LED Current Range ILED Value TYP 1.86 1.80 1.21 1.18 90 5 5.0 4.0 0.2 2.0 2.0 1.3 1.3 400 0.1 95 ● MAX 35 10 10 4.25 0.2 920 1000 V mA μA V V MHz MHz MHz MHz mΩ μA % ns V V mV mV 120 mA 2.14 2.17 1.39 1.42 800 1.0 50 4.55 ● 680 600 ● 10 4.9 0.1 800 800 Unit Condition After start up PWM =0V *1 UVLO On VIN UVLO Off VIN RT=55kΩ RT=91kΩ ILX=+30mA VLX=45V FOSC=1.3MHz ICOMP=-10μA ICOMP=+10μA RISET=36 kΩ RISET=36kΩ 73.15 75.8 78.46 mA I LED _ TYP ( mA ) = ILED_TYP1 I CH (1− 3) MAX + I CH (1− 3) MIN 2 RISET=36kΩ ● 72.39 75.8 79.21 mA I LED _ TYP ( mA ) = I CH (1− 3) MAX + I CH (1− 3) MIN 2 RISET=91kΩ LED Current 28.8 30.0 31.2 mA I LED _ TYP ( mA ) = ILED_TYP2 I CH (1− 3) MAX + I CH (1− 3) MIN 2 RISET=91kΩ ● 28.5 30.0 31.5 mA I LED _ TYP ( mA ) = I CH (1− 3) MAX + I CH (1− 3) MIN 2 RISET=42kΩ ILED_TYP3 ● 62.08 65.0 67.93 mA I LED _ TYP ( mA ) = MS1348-E-00 5 I CH (1− 3) MAX + I CH (1− 3) MIN 2 2012/05 ［AP2152］ Electrical Characteristics (continuation) Parameter Symbol MIN Value TYP MAX Unit Condition RISET= 36kΩ, ILED_TYP=75.8mA ΔILED1 -2.5 ±0.8 +2.5 % △I LED (%) = I CH (1− 3) MAX − I CH (1− 3) MIN I CH (1− 3)MAX + I CH (1− 3) MIN LED Current Accuracy Between Channels × 100 RISET= 91kΩ, ILED_TYP=30.0mA ΔILED2 -5.0 ±1.5 +5.0 % △I LED (%) = I CH (1− 3) MAX − I CH (1− 3) MIN I CH (1− 3)MAX + I CH (1− 3) MIN × 100 RISET= 42kΩ, ILED_TYP=65.0mA ΔILED3 ● -2.5 ±0.8 +2.5 % △I LED (%) = I CH (1− 3) MAX − I CH (1− 3) MIN I CH (1− 3)MAX + I CH (1− 3) MIN tr ● 1 tf ● μs LED Current Rising Time to PWM Input RT=55kΩ LED Current Falling Time to PWM Input RT=55kΩ VIN=12V, IDC=10mA 2 LED Current Delay Time 0.5 1 4.75 4.50 5.0 5.0 5.25 5.50 V V 1.15 10.8 1.2 12 2.6 1.25 13.2 1.9 8 0.2 2.1 2.0 10 V V A Ω V μA MHz V V LDO Output Voltage Protection Function OVP Reference Voltage LED Short Criterion Voltage LX Limited Current PGOOD On Resistance TM Voltage TM Constant Output Current Switching Frequency Range Input High Level Voltage Input Low Level Voltage CLKO Output High Level Voltage CLKO Output Low Level Voltage MS1348-E-00 VDC VOVP VSHT ILX_LIMIT RPGOOD VTM ITM FOSC VIH VIL VOH_CLKO ● ● ● ● ● 100 2.1 12 2.5 0.7 4.0 VOL_CLKO 0.3 6 × 100 CH1~CH3 pin IPGOOD=+10mA TM=1.0V PWM, SCLK, SYNC PWM, SCLK, SYNC V ICLKO=-1mA V ICLKO=+1mA 2012/05 ［AP2152］ *1. Normally, when 4.25V is applied to VIN for shorter than 100μs, while the PWM pin is kept at a low level, the IC will be in the standby mode. However, if 4.25V is applied to VIN for longer than 300μs, the current consumption of the IC is about 900μA. In order to get the IC into standby mode, after inputting a H level to the PWM pin for more than 36μs , a L level needs to be maintained for more than 50ms. 300µs or longer 4.2V VIN 0 36µs or longer PWM 0 IDD approx 5µA approx 5mA approx 900µA 50ms or longer Standby mode Figure 3. Power Supply Rising Time and Standby mode Interface (AC Timing) Parameter Value TYP MAX ● 15 15 30 36 μs μs Before Startup Before Startup TPWM_MIN2 ● 5 7 μs After Startup TSD ● 30 50 ms 0.1 20 kHz Symbol PWM PWM Minimum High Time 1 PWM Minimum High Time 2 Shutdown Time PWM Dimming Frequency Range SYNC SYNC Input Frequency Range SYNC Input Duty Serial Timing SCLK Cycle SCLK Pulse Width SDATA Delay TPWM_MIN1 MIN FPWM 20 Unit FSYNC ● 0.21 2.5 MHz DSYNC ● 20 80 % tSCKP tSCKW tSDTW 10 5 3 Condition FPWM≤FOSC / 65 μs μs μs tSCKP tSCKW tSCKW SCLK tSDTW SDATA Figure 4. Serial Interface Wave Form MS1348-E-00 7 2012/05 ［AP2152］ OPERATION 1) Operation Outline The AP2152 is composed of a current mode DC/DC boost convertor, 3 LED constant current source channels, an LDO, and several protection circuits. It can drive a single LED line to three LED lines connected together with a common anode. (Any unused channel should be left open) This current mode DC/DC boost convertor has a built-in a power MOSFET, and the switching frequency is determined by an external resistor or an external clock signal. The LED anode voltage is optimized by monitoring each channel’s voltage and the channel voltage that has the highest forward voltage is chosen. This voltage is used to control the DC/DC boost convertor’s output voltage . constant current circuits for driving the LEDs are set by an external resistor, and PWM dimming is possible by applying a PWM signal to the PWM pin. The latch-off time for the protection circuits, such over current protection, channel short protection, and thermal protection can be set. There is also a PGOOD pin to output the latch-off status. The AP2152 flowchart at startup is shown in Figure 5. When all CH pins are used, applying a PWM signal begins the DC/DC boost convertor operation. The LED anode voltage rises, and if the LED current of all the CH reaches 1/10 of the set current, the soft-start circuit is activated and the LED current gradually increases in approximately 1ms, and LEDs are lit. If there are any unused CH pins, the LED open detection circuit is activated at the beginning of the DC/DC boost converter operation as soon as the PWM signal is applied. When the LED anode voltage reaches the OVP preset value, the OVP state is detected. If a CH pin has not reached 1/10 of the LED set current, an open state is recognized, and the LED constant current circuit will cease. For CH pins connected to LEDs, the LED current reaches 1/10 of the set current, the normal connection is recognized, and the LEDs are lit after the soft-start operation. Apply power Apply PWM Delay time 30µs Reference Voltage→ ON. 300µs delay VDC →ON. Power on Reset. Initial determination mode Boost circuit/constant current circuit operation continues regardless the PWM signal level (high/low). Boost circuit ON. Constant current circuit (1/10 of the set current) ON. All CH pin are used(3CHs). 1/10 of the set current flows to all 3 CH constant current circuits. 1 or 2CHs is/are used. Vout reaches the OVP voltage. Tsw×1920 Exclude open CH from DC/DC control. When a current is not flowed on the constant current circuit in the CH. Operate LED current soft start 1ms Normal operation Figure 5. Flowchart at startup MS1348-E-00 8 2012/05 ［AP2152］ 2) Functions 2-1) PWM Input circuit The AP2152 achieves PWM dimming by applying a PWM signal to the PWM pin. The PWM pin is also used as the enable function of the IC. At startup, if a high level PWM signal is applied to the PWM pin and maintained for more than 36us, the standby mode will be released. If the high level of PWM signal within the range of 50Hz~20kHz(FPWM≤FOSC / 65), is applied longer than 7us to the PWM pin after releasing the standby mode, the operation mode is maintained and direct PWM dimming by PWM signal is simultaneously conducted. The LED current will be the set current configured by the RISET resistor during a high level of the PWM dimming signal, and the current will be 0mA during a low level of the PWM dimming signal. If a low level PWM signal is maintained longer than 50ms after the LED is lit, the IC will be in the standby mode. 2-2) 5V Regulator The AP2152 has a built in low dropout linear regulator to supply voltage for the internal circuits. If a low level is applied to the PWM pin, the VDC is approximately 0V, and if a high level is applied to the PWM pin, the VDC outputs 5V. The VDC pin, the output of the LDO, outputs 5V while the supply voltage ranges from 6V to 35V. If the supply voltage is less than 6V, the output voltage decreases depending on the supply voltage. If the supply voltage goes below the UVLO voltage, the IC ceases operation. If the supply voltage is between the UVLO voltage and 6V, the IC operates but the characteristics are not guaranteed. Please connect 1uF capacitor between the VDC pin and GND. 2-3) LED current setting The AP2152 has 3 channel LED constant current circuits built in. By connecting 10 LEDs in series per channel, a maximum of 30 LEDs can be driven. Maximum LED current per channel is 120mA. The LED current can be set in the range from 10mA to 120mA by connecting an external resistor RISET between the ISET pin and GND. If the ISET pin is affected by noise, the LED current becomes unstable, so RISET should be placed as close to the IC as possible. The ISET pin sets the LED current for all channels. (CH1~CH3) The following shows the approximate expression for the LED current and the RISET connected to the ISET pin. Please check the LED current (thoroughly) when designing the actual board. 2730 ILED(mA ) = R ISET (kΩ) 2-4) Switching frequency setting/Synchronize with external clock The AP2152 can set the DC/DC boost converter switching frequency in the range from 0.2MHz to 2.5MHz by connecting an external resistor RT between the RT pin and GND. If the RT pin is affected by noise, the switching frequency becomes unstable, so RT should be placed as closer to the IC as possible. The AP2152 switching frequency can be synchronized to an external clock signal. If an external clock signal is applied to the SYNC pin, the switching frequency synchronizes to the external clock’s rising edge. If a low level is applied to the SYNC pin for approximately 10us during the synchronization operation, it becomes self-oscillating. (If low level is applied to the SYNC pin in the synchronization operation for approximately 10us, it becomes self-oscillation operation.) The external clock frequency and the switching frequency set by RT should be the same. The following shows the approximate expression of the switching frequency and RT on the RT pin. Please check (thoroughly) when designing the actual board. FOSC (MHz ) = MS1348-E-00 10 3 7.695 × R T (kΩ) + 80 9 2012/05 ［AP2152］ 2-5) Over voltage protection (OVP)/OVP pin short protection In order not to exceed the internal MOSFET breakdown voltage, the AP2152 has built in over voltage protection. The OVP pin monitors the LED anode voltage divided by the resistor divider. If the OVP pin voltage exceeds 1.20V, the IC ceases boost operation. The LED constant current source maintains operation. If the OVP pin voltage becomes less than 1.20V, the boost operation is resumed. The over current protection function prevents damage by suppressing an overvoltage condition (excessive LED anode voltage) when the load is reduced. This can occur when there is an open condition across one of the LED lines or when the supply voltage fluctuates rapidly. OVP Voltage = (1 + R ovp 2 R ovp1 ) × OVP Reference Voltage OVP reference voltage 1.2V (typ) The OVP set voltage should be set more than the total voltage of the maximum forward voltage of the LED line plus the error amplifier reference voltage to correctly detect an LED open condition. However the total voltage needs to be less than the Nch power MOSFET maximum rating voltage. The OVP pin short protection is built in. It is activated when the OVP pin voltage becomes less than 0.1V, which is caused by an open across the external Schottkey diode. If the OVP pin short protection is activated, the boost DC/DC convertor operation and the LED constant current circuit ceases, the internal FET for PGOOD is turned on. 2-6) Timer Latch (TM pin) setting The AP2152 has a built in timer latch type protection circuit. The latch time for the protection circuit is set by connecting an external capacitor CTM between the TM pin and GND. When channel short protection, over current protection, OVP pin short protection, or thermal protection is activated, CTM which is connected to the TM pin is charged by a 10uA constant current. However, the TM pin becomes Hi-Z (high impedance) while PWM = low and the TM pin voltage is maintained. When the protection circuits continue their operation, the charging of CTM also continues. If the TM pin voltage reaches 2.0V, the DC/DC boost convertor and the LED constant current circuits are latched off and the internal FET for PGOOD is turned on. In order to restart the IC after it has been turned off by the timer latch function, a low level for more than 50ms needs to be maintained on the PWM pin or the supply voltage needs to be pulled down below the UVLO voltage. The following shows the approximate expression of the timer latch time and CTM connected on the TM pin. Please check (thoroughly) when designing the actual board. Timer latch time TTM (ms ) = 200 × C TM (µF) 2-7) Thermal protection The AP2152 has a built in thermal protection circuit. If the IC goes into and maintains a high temperature state, the IC will be latched off, therefore the IC needs to be operating below the thermal protection circuit minimum (activation) temperature of 125°C. 2-8) LED open protection The AP2152 can be operated with one, two or three channels connected. There is not a problem if a CH pin is left open. . For this operation, the AP2152 has a built in LED open detection circuit. If an open CH pin is detected, the CH pin becomes a high impedance and is excluded from the control circuit of the DC/DC boost converter. If all three CH pins are open, the DC/DC boost converter and the LED constant current circuits are completely turned off. If a capacitor is connected in parallel with the LED line and the LED line is opened, the open detection circuit may not work correctly. MS1348-E-00 10 2012/05 ［AP2152］ 2-9) LED short protection and Cout setting The AP2152 has a built in LED short protection circuit. If an LED is broken as a short state and the CH pin voltage exceeds 10.8V, the corresponding constant current circuit will be ceased. If there is an unused CH pin, the LED anode voltage increases up to the OVP setting voltage by the LED open detection circuit. In this case, the CH pin temporarily increases and becomes the same state as the LED short protection, in order to distinguish this case from LED short protection operation, the opened CH pin is excluded using the IC internal counter. For this operation, the Cout value is constrained, so Cout should be determined using the following formula. LED short protection count time＞CH pin voltage rising time (10.8V or higher) ①LED short protection count time = ② CH pin voltage rising time = 1 × 1920 Fsw Cout × ( Vovp( max ) - LEDVf (min ) - 10.8 V ) Iout × 0.95 2-10) PGOOD function The PGOOD pin is an Nch open drain output. The internal FET on the PGOOD pin stays off when the supply voltage is 0V (If the PGOOD pin is connected to a pull-up resistor, the PGOOD pin becomes high level) If the supply voltage reaches to approximately 2V, the internal circuits are biased and the internal PGOOD FET turns on. If the supply voltage is more than UVLO and the PWM pin is high, the standby circuit will be released, the IC recognizes as normal operation and the internal PGOOD FET turns off. If a protection circuit is activated after normal operation, the internal PGOOD turns on. (Relationship between protection function and the PGOOD pin state is later described in “Protection Function”). By applying a PWM low level for longer than 50ms, the IC will be reset and the internal PGOOD FET turns on in a standby state. When the LED anode is shorted to GND, the internal PGOOD FET immediately is turned on by the OVP pin short circuit protection and the PGOOD signal can be used to cut the path from VIN to the LED anode. (Refer to Figure 7) The AP2152 employs a timer latch method for protection functions. If the FET over current protection, thermal protection, CH short protection, LED open protection, or LED short protection is activated, the IC is latched off and turns off the LEDs. For example, when the PGOOD pin is monitored by a microcomputer and an abnormal state (PGOOD pin with pull-up resistor is low level) is detected, the microcomputer controls a restart sequence after the IC is reset, so a highly stable system configuration is possible. MS1348-E-00 11 2012/05 ［AP2152］ Internal Nch FET on PGOOD pin operation ●Turn off during normal operation ●Turn on when abnormal operation Timer latch off (Over current, CH short, Thermal protection), all CH are open or short, UVLO ●Turn on when in standby state while supply voltage (VIN) is applied. Turn off when VIN is less than 2V ●Turn on without delay by timer circuit when OVP pin short is detected. VIN VIN PWM About2V About 2V 30ms typ VPWM 0 . 3ms typ LED setting current 1 /10 * ILED ILED 1ms LED Current Soft Start Initial determination OFF OFF ON ON OFF PGOOD Figure6. VIN PGOOD pin operation D L C IN 1 LED Anode C OUT 1 C OUT 2 1 LX 3. 3V PGOOD 15 C IN 2 Figure7. MS1348-E-00 8 VIN Cut off VIN-LED anode path by using an external FET (example) 12 2012/05 ［AP2152］ 2-11) Serial interface The AP2152 has a built in read only serial interface. By inputting a CLK signal to the SCLK pin, data can be read from the SDATA pin synchronizing with the CLK rising edge. The SDATA pin is an Nch open drain output. The pin needs to be pulled-up to the external power supply. CH1 CH2 CH3 TM SDATA Low Low Low Low State LED OPEN or SHORT ⇒ CH1 shutoff LED OPEN or SHORT ⇒ CH2 shutoff LED OPEN or SHORT ⇒ CH2 shutoff Shut-off state by timer latch SCLK SDATA CH1 CH2 CH3 TM RESET CH1 Figure8. Serial Interface Timing Chart MS1348-E-00 13 2012/05 ［AP2152］ 3) Protection Function Protection Thermal Over current Over voltage (OVP) OVP pin short UVLO LDO short CH short LED open LED short ISET short RT short Detection time Shut-off state Detection condition Release condition PGOOD TTM *2 Latch off 125℃min *1 ON TTM *2 Latch off 2.6A *1 ON LED anode voltage control Auto-release More than 1.2V 1.2V or less OFF Cease all Auto-release ↓ TTM *2 Latch off Lass than 0.1V More than 0.1V ↓ *1 ON Cease all Auto-release 3.75Vmin 4.45Vmax ON Cease all Auto-release More than 30mA 30mA or less OFF TTM *2 Latch off 0.1V *1 ON If the CH pin is opened due to an LED disconnection or destruction as an open state, the CH pin is latched off. Internal timer each CH Latch off Less than LED set current when OVP Voltage *1 OFF *3 If the CH pin voltage reaches the detection condition due to destruction by an LED short, the CH pin is latched off. To prevent heat generation due to increases in the LED current when the ISET pin shorts to GND, the Nch power MOSFET operation is ceased. If the short state goes away, the IC resumes the normal operation. To prevent heat generation due to increases in the switching frequency when the RT pin shorts to GND, the Nch power MOSFET operation is ceased. If the short state goes away, the IC resumes the normal operation. Internal timer each CH Latch off 12V *1 OFF *4 Cease Nch Power MOSFET Auto-release ISET pin GND short ISET pin normal 1V OFF Cease Nch Power MOSFET Auto-release RT pin GND short RT pin Normal 1V OFF Description When the IC temperature rises and reaches the detection condition and exceeds the detection time, the DC/DC boost converter and the LED constant current circuit are latched off. Internal Nch power MOSFET drain current is monitored by using an internal detection resistor. If exceeding the detection condition, the power MOSFET is turned off. And if exceeding the detection time, the DC/DC boost converter and the LED constant current circuit are latched off. If the OVP pin voltage reaches the detection condition, the DC/DC boost converter is immediately shut off. In this case, the LED constant current circuit is still operating If the OVP pin reaches the detection condition caused by the OVP pin shorted to GND, the LED anode shorted to GND or the Schottky diode open, the DC/DC boost converter and the LED constant current circuit are immediately shut off and the internal PGOOD FET is turned on. If the OVP pin voltage reaches the release condition, normal operation is resumed. If exceeding the detection time, the DC/DC boost converter and the LED constant current circuit are latched off. To prevent malfunction of the IC when the VIN voltage reaches the detection condition. Circuits excluding the UVLO circuit stop the operation. If the VIN voltage returns to the release condition, the IC resumes normal operation. To prevent malfunction and over heating of the IC when the VDC pin shorts to GND. The LDO current is limited to low levels. If the short state goes away, the IC resumes normal operation. When the CH pin shorts to GND, the voltage reaches the detection condition, and exceeds the detection time, the DC/DC boost converter and the LED constant current are ceased. Note: *1. In order to release the latch off state, the PWM pin should be maintained at a low level for 50ms or longer or the supply voltage should be pulled down less than the UVLO voltage. *2. Set time by external capacitor on the TM pin. Refer to the timer latch setting. *3. OFF when 1 CH or 2 CHs out of 3 CHs is/are open state, ON when all 3 CHs are open state. *4. OFF when 1 CH or 2 CHs out of 3 CHs is/are short state, ON when all 3 CHs are short state. MS1348-E-00 14 2012/05 ［AP2152］ APPLICATION (example) Input voltage LED LED anode voltage LED current Vin=8.5V~16V 2 lines in parallel 9 LEDs in series 22.3V-32.6V 55mA/line VO UT VIN D L C IN1 R OVP2-1 C OUT1 C OUT2 R OVP2-2 RCOMP CCOMP 1 C COMP 2 1 LX PGND 2 15 R OVP1 11 10 COMP OVP CH1 19 CH2 18 CH3 17 PGOOD 14 TM 8 VIN C TM SCLK 4 C IN2 SDATA VDC 3 9 C VDC SYNC PWM GND RT ISET 6 5 20 12 13 4 CLKO RT R ISET R SYN C PWM INPU T Figure 9. External circuit connection example A recommended BOM Resistor Capacitor Diode Inductor Symbol RT ROVP1 ROVP2-1 ROVP2-2 RISET RCOMP RSYNC CIN1 CIN2 CVDC CTM CCOMP1 CCOMP2 COUT1, 2 D L P/N short GRM31CR71H475K CM21X5R105M50A CM05X5R105M06A CM05X5R104M10A CM05X5R473M16A open GRM31CR71H225K #A921CY-150M Value 55kΩ ±0.5% 30kΩ ±0.5% 430kΩ ±0.5% 470kΩ ±0.5% 49.7kΩ ±0.5% 1kΩ ±1% 0Ω 4.7uF/50V 1.0uF/50V 1.0uF/6.3V 0.1uF/10V 0.047uF/16V 2.2uF/50V 60V，Io=1A D63LCB 15uH Maker MURATA KYOCERA KYOCERA KYOCERA KYOCERA MURATA TOKO Note SW frequency 2MHz OVP voltage 37.2V OVP voltage 37.2V OVP voltage 37.2V LED current 55mA Phase compensation Self resonant freq. Input capacitor Capacitor for the IC For VDC stability Timer latch setting Phase compensation Output capacitor - Values in this table are for reference only. MS1348-E-00 15 2012/05 ［AP2152］ Characteristics Ta=25°C, PWM=3.3V LED current vs. Supply voltage (reference only) LED current vs. PWM Duty VIN=12V、 、PWM 200Hz PWM Signal Duty vs. ILED Vin vs. LED Current 60 60 ILED_CH1 58 50 56 40 ILED (mA) ILED (mA) ILED_CH2 54 30 20 52 ILED_CH1 10 ILED_CH2 50 8 10 12 14 0 16 0 Vin(V) 20 40 60 80 100 PWM Signal Duty(% ) Efficiency vs. Supply voltage Phase margin VIN=12V Vin vs. Efficiency 95 90 Efficiency(%) 85 80 75 70 65 8 9 10 11 12 13 14 15 16 Vin(V) Start-up wave form VIN=12V PWM Duty 100% MS1348-E-00 Start-up wave form VIN=12V PWM Duty 0.8% 200Hz 16 2012/05 ［AP2152］ PACKAGE and MARKING 1) Dimension（ （20 pin HTSSOP） ） Mark 1 10 （3.2） 5.7 11 4.4 ±0. 1 20 0.8 0.375 （4.32） 0.235 ±0.04 0.65 0.10 M Reference Mount Pad 0.14 ±0.035 6.5 ±0.1 1.20 max 1.0 ±0.1 0.65 Date code Lot No S 6.4 ±0.2 0.25 0.10 0.10 ±0.05 S （3.0） 0°~10° 0.60 ±0. 1 （4.12） MS1348-E-00 17 2012/05 ［AP2152］ 2) Marking AP2152 XXX XXXX Upper Product name：AP2152 Center Assembly lot number: 3 digits Lower Date code: 4 digits 1 digit (last digit of year) + 2 digits (weekly code) + 1 digit (lot number) IMPORTANT NOTICE These products and their specifications are subject to change without notice. When you consider any use or application of these products, please make inquiries the sales office of Asahi Kasei Microdevices Corporation (AKM) or authorized distributors as to current status of the products. Descriptions of external circuits, application circuits, software and other related information contained in this document are provided only to illustrate the operation and application examples of the semiconductor products. You are fully responsible for the incorporation of these external circuits, application circuits, software and other related information in the design of your equipments. AKM assumes no responsibility for any losses incurred by you or third parties arising from the use of these information herein. AKM assumes no liability for infringement of any patent, intellectual property, or other rights in the application or use of such information contained herein. Any export of these products, or devices or systems containing them, may require an export license or other official approval under the law and regulations of the country of export pertaining to customs and tariffs, currency exchange, or strategic materials. AKM products are neither intended nor authorized for use as critical componentsNote1) in any safety, life support, or other hazard related device or systemNote2), and AKM assumes no responsibility for such use, except for the use approved with the express written consent by Representative Director of AKM. As used here: Note1) A critical component is one whose failure to function or perform may reasonably be expected to result, whether directly or indirectly, in the loss of the safety or effectiveness of the device or system containing it, and which must therefore meet very high standards of performance and reliability. Note2) A hazard related device or system is one designed or intended for life support or maintenance of safety or for applications in medicine, aerospace, nuclear energy, or other fields, in which its failure to function or perform may reasonably be expected to result in loss of life or in significant injury or damage to person or property. It is the responsibility of the buyer or distributor of AKM products, who distributes, disposes of, or otherwise places the product with a third party, to notify such third party in advance of the above content and conditions, and the buyer or distributor agrees to assume any and all responsibility and liability for and hold AKM harmless from any and all claims arising from the use of said product in the absence of such notification. MS1348-E-00 18 2012/05