advanced power electronics corp. 1.9a fixed frequency white led driver features description 2.5v to 5.5 v operating input voltage rang drives up to 8 series white leds 1.2mhz fixed switching frequency wide range for pwm dimming (200hz to 200khz) internal 1.9a switching current limit over voltage protection (ovp) internal soft-start function current limit and thermal shutdown protection under voltage lockout available in the tsot-26 packages 1. 8 series led application 2. led dimming application data and specifications subject to change without notice 201203211 ape1612 typical application 1 the ape1612 is a step-up converter designed fo r driving up to 8 series white leds for backlighting application. the ape1612 uses current mode, 1.2mhz fixed frequency architecture to regulate the led current, which is set through an external current sense resistor. its low 300mv feedback voltage reduces power loss and improves efficiency. the ov pin monitors the output voltage and turns off the converter i f an over-voltage condition is present due to an open circuit condition. the ape1612 includes under-voltage lockout, current limiting and thermal shutdown protection preventing damage in the event of an output overload. the driver is available in tsot-26 packages. vin=5v c1 4.7uf l1 4.7uh u1 ape1612 vcc en ov gnd sw c2 1uf d1 b240a i led =v fb /r3, v fb =300mv 200~200khz fb r3 8-wleds dimming vin=5v c1 4.7uf l1 4.7uh u1 ape1612 vcc en ov gnd sw c2 1uf d1 b240a i led =v fb /r3, v fb =300mv on off fb r3 8-wleds
advanced power electronics corp. ape1612 absolute maximum ratings (at t a =25c) vcc pin voltage (v cc ) ----------------------------------- - gnd - 0.3 to gnd + 6v en, fb, ov pin voltage ---------------------------------- - gnd - 0.3 to vcc + 0.3v sw pin voltage (v sw ) ------------------------------------ - 30v power dissipation(p d ) ------------------------------------ - ( t j -t a ) / rth ja mw storage temperature range(t st ) --------------------- - -65c to 150c operating junction temperature range(t op ) ------ - -40c to 125c 180c/w 250c/w note: rth ja is measured with the pcb copper area of approximately 1 in 2 (multi-layer) ordering / package information electrical specifications (v cc =5v, i out = 20ma, t a = 25 o c, unless otherwise noted) parameter sym test condition min typ max units input voltage range v cc 2.5 - 5.5 v step-up voltage range v out 3 - 27 v ov sense voltage v ov 27.5 29 30.5 v under voltage lockout u vlo rising - 2.25 2.45 v uvlo hysteresis - 100 - mv feedback voltage v fb 285 300 315 mv v ih 1.4 - - v v il - - 0.4 v en hysteresis - 200 - mv operating quiescent current i ccq i out = 0ma, v fb =0.5v - 170 - a shutdown current i sd v en =0v, t en > 20ms - - 1 a n-channel mosfet curren t limit ( note1 ) i lim duty=50% - 1.9 - a v cc =3v, i sw =1a - 650 - v cc =5v, i sw =1a - 500 - maximum duty cycle d max 85 90 - % line regulation v cc = 3v to 5v - 1 - % switching frequency f osc 0.9 1.2 1.5 mhz dimming clock rate f dim 0.2 - 200 khz 2 mosfet on-resistance (note1) r ds(on) m thermal resistance from junction to case(rth jc ) thermal resistance from junction to ambient(rth ja ) en threshold ape1612 x package type ty : tsot-26 (top view) tsot-26 3 2 6 4 1 gnd vcc sw ov 5 fb en logic-high voltage logic-low voltage
advanced power electronics corp. ape1612 electrical specifications parameter sym test condition min typ max units fb input leakage current i fb-lkg v fb = 0.5v - 0.01 100 na sw leakage current i swl v lx = 27v, v fb =0.5v - - 1 a i en-lkg1 v en = v cc - 1.5 3 a i en-lkg2 v en = gnd - 0.01 0.1 a shutdown delay t shdn -10-ms thermal shutdown t sd - 150 - thermal shutdown hysteresis t sh -30- note1 : guaranteed by design. pin descriptions pin symbol pin description vcc power input pin en enable with dimming pin, internal pull-high. fb feedback pin; put a resistor to gnd to setting the current gnd ground pin ov ovp sense pin sw switch output pin block diagram 3 en input leakage current o c vcc sw control and driver logic en reference 1.238v soft start current sense slope compensation oscillator 1.2mhz fb error amplifier summing comparator thermal shutdown enable logic gnd n-mos 10ms 300mv shutdown ovp ov uvlo
advanced power electronics corp. ape1612 application information setting the iled current over voltage protection under voltage lockout (uvlo) input capacitor selection output capacitor selection 4 the output capacitor is required to keep the output voltage ripple small and to ensure regulation loop stability. the output capacitor must have low impedance at the switching frequency. ceramic capacitors with x5r or x7r dielectrics are recommended due to thei r low esr and high ripple current. a 1uf ceramic capacitors works for most of the applications. higher capacitor values can be used to improve the load transient response. application circuit item shows the basic application circuit with ape1612 adjustable output version. the external resistor sets the led output current according to the following e q uation: ? ? ? ? ? ? = 3 3 . 0 r v i led to avoid mis-operation of the device at low input voltages an under voltage lockout is included that disables the device, if the input voltage falls below (2.25v-100mv). the input capacitor reduces the surge current drawn from the input and switching noise from the device. the input capacitor impedance at the switching frequency shall be less than input source impedance to prevent high frequency switching current passing to the input. a low esr input capacitor sized for maximum rms current must be used. ceramic capacitors with x5r or x7r dielectrics are highly recommended because of thei r low esr and small temperature coefficients. a 4.7 f ceramic capacitor for most applications is sufficient. for a lower output power requirement application, this value can be decreased. i led 20ma 15 ? 6mw 350ma 0.857 ? 105mw r3 ov measure the output voltage for open circuit protection. connect ov pin to the output at the top of the led string. if v out above 29v, the ovp protection is happened that stops the internal driver until v out below 29v.
advanced power electronics corp. ape1612 typical performance characteristics 5 frequency vs. input voltage frequency vs. temperature efficiency vs. output current efficiency vs. input voltage output voltage vs. output current quiescent current vs. input voltage
advanced power electronics corp. ape1612 typical performance characteristics 6 led current vs. duty enable threshold vs. input voltage reference voltage vs. input voltage reference voltage vs. temperature power on from vin power on from en
advanced power electronics corp. ape1612 typical performance characteristics 7 steady state operation normal operation into ovp pwm dimming from en (200hz) pwm dimming from en (20khz) ( v out , i out : measured by ac coupled mode )
advanced power electronics corp. ape1612 marking information tsot-26 8 jayws part number : ja year : a = 2010 1 = 2011 week: a~z : 01~26 a~z : 27~52 id code : internal
package outlines e1 e e e1 b d a a1 a2 y l1 r l c l2 dimensions in millimeters dimensions in inches symbol min. nom. max. min. nom. max. a - - 1.10 - - 0.043 a1 0.00 - 0.10 0 - 0.004 a2 0.70 0.90 1.00 0.028 0.035 0.039 b 0.30 0.40 0.50 0.012 0.016 0.020 c 0.08 0.14 0.20 0.003 0.006 0.008 d 2.80 2.90 3.00 0.110 0.114 0.118 e 2.60 2.80 3.00 0.102 0.110 0.118 e1 1.50 1.60 1.70 0.059 0.063 0.067 e 0.95 bsc. 0.037 bsc. e1 1.90 bsc. 0.075 bsc. l 0.30 0.45 0.60 0.012 0.018 0.024 l1 0.60 ref. 0.024 ref. l2 0.25 bsc. 0.010 bsc. y - - 0.10 - - 0.004 r 0.10 - - 0.004 - -
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