View IK3401_4644746.PDF datasheet online --- IC-ON-LINE

Datasheet File OCR Text:

technical data rev 00 green mode pwm controller description the IK3401 is a green mode pwm controller. it is specially designed for dvdp, stb and lcd monitor application. to minimize standby power consumption, a green-mode function provides off-time modulation to continuously decrease the switching frequency at light-load conditions. under zero-load conditions, the power supply enters burst- mode. to avoid acoustic noise problem, the minimum pwm frequency set above 20khz. this green-mode function enables the power supply to easily meet international power conservation requirements. to further reduce power consumption, IK3401 is manufactured by using the hv-cmos process. this allows the lowest start-up current around 14ua, and the operating current is only 4ma. as a result, large start-up resistance can be used. the maximum power can be limited constantly, regardless of the line voltage change using power limit function. the switching frequency is programmable or internally fixed to be 65khz. IK3401 integrates frequency modulation technique internally. the frequency jittering function helps reduce emi emission of a power supply with minimum line filters. also, its built-in synchronized slope compensation achieves stable peak-current-mode control. IK3401 provides many protection functions. in addition to cycle-by-cycle current limiting, the internal open-loop protection circuit ensures safety should an open loop or output short-circuit failure occurs. pwm output is disabled till vdd drops below the uvlo lower limit. then, the controller starts up again. as long as vdd exceeds about 24v, the internal ovp circuit is triggered. for ovp and otp, the protection mode can be chosen to be latch off or auto recovery. IK3401 is available in an 8-pin dip or sop package. features green-mode pwm control low start-up current (typ. 14ua) low operating current (typ. 4ma) programmable pwm frequency with frequency jittering peak-current-mode control cycle-by-cycle current limiting synchronized slope compensation applications notebook power adapters dvd-p, stb, lcd monitor power open-frame smps IK3401 leading-edge blanking constant output power limit totem pole output with soft driving vdd over voltage protection (ovp) 150c otp with hysteresis internal latch circuit (ovp, otp) internal open-loop protection vdd under-voltage lockout (uvlo) gate output maximum voltage clamp (18v)
IK3401 rev 00 pin configuration pin symbol pin description 1 gnd ground 2 fb feedback 3 vin start-up input 4 ri reference setting 5 nc - 6 sense current sense 7 vdd ic power supply 8 gate gate drive output
IK3401 rev 00 block diagram absolute maximum ratings (ta = 25 c, unless otherwise specified) symbol parameter value unit v dd supply voltage 25 v v in input terminal 25 v v fb input voltage to fb pin -0.3 to 7v v v sense input voltage to sense pin -0.3 to 7v v v ri input voltage to ri pin -0.3 to 7v v p d power dissipation at t a < 50c dip sop 800 400 mw r j-a thermal resistance junction-air dip sop 82.5 141 c t j operating junction temperature -40 to 125 c t stg storage temperature range -50 to 150 c t l lead temperature 260 c hbm esd capability, hbm model 3.0 kv mm esd capability, mm model 250 v
IK3401 rev 00 electrical characteristics (v dd = 15v, t a = 25c, unless noted) vdd section symbol parameter test condition min. typ. max. unit v op continuously operating voltage 22 v v th-on turn-on threshold voltage 15.5 16.5 17.5 v v th-off turn-off voltage 9.5 10.5 11.5 v i dd-st start-up current 14 30 ua i dd-op operating supply current gate open 4 5 ma v dd-ovp v dd over voltage protection 23.2 24.2 25.2 v t vdd-ovp v dd ovp debounce time 100 usec ri section symbol parameter test condition min. typ. max. unit r inor r i operating range 15.5 36 k? ri max max. r i value for protection 230 k? ri min min. r i value for protection 10 k? oscillator section symbol parameter test condition min. typ. max. unit center frequency 62 65 68 khz f osc normal pwm frequency jitter range r i = 26k ? 3.7 4.2 4.7 khz t jtr jittering period r i = 26k ? 3.9 4.4 4.9 ms f osc-g-min min. r i value for protection r i = 26k ? 18 22 25 khz f dv frequency variation vs v dd deviation 5 % f dt frequency variation vs temp. deviation 5 %
IK3401 rev 00 feedback input section symbol parameter test condition min. typ. max. unit a v fb input to current comparator attenuation 1/4.5 1/4 1/3.5 v/v z fb input impedance 4 7 k? v fb-open output high voltage fb pin open 5.5 v v fb-olp fb open-loop trigger level 5 5.4 v/v t d-olp fb open-loop protection delay r i = 26k ? 50 56 62 ms v fb-n green-mode entry fb voltage r i = 26k ? 1.9 2.1 2.3 v v fb-g green-mode ending fb voltage r i = 26k ? v fb-n -0.6 v fb-n - 0.5 v fb-n - 0.4 v f g-test burst mode test frequency v fb-g +20mv f osc-g-min +0.5 khz i fb-zdc zero duty fb current 1.5 ma current sense section symbol parameter test condition min. typ. max. unit z sense input impedance 12 k? v sthfl current limit flatten threshold voltage 0.85 0.9 0.95 v v sthva current limit valley threshold voltage v sthfl -v sthva 0.22 v dcy saw duty cycle of saw limit max. duty cycle 45 % t pd propagation delay to gate output r i =26 k ? 150 200 ns t led leading edge blanking time r i =26 k ? 200 270 350 ns
IK3401 rev 00 gate section symbol parameter test condition min. typ. max. unit dcy max maximum duty cycle 80 85 90 % v gl output voltage low v dd =15v, i o =50ma 1.5 v v gh output voltage high v dd =12v, i o =50ma 8 v t r rising time v dd =15v, c l =1nf 150 250 350 ns t f falling time v dd =15v, c l =1nf 30 50 90 ns i o peak output current v dd =15v, gate=6v 230 ma v clamp gate output clamping voltage v dd =23v 18 19 v over temperature protection (otp) symbol parameter test condition min. typ. max. unit temp-off protection junction temperature*1 150 c temp- restart restart junction temperature*2 130 c *1) when activated, the output is disabled and the latch is turned off. *2) this is the threshold temperature for enabling the output again and resetting the latch, after over temperature protection has been activated. typical characteristics
IK3401 rev 00
IK3401 rev 00 operation description start-up current the typical start-up current is only 14ua. this allows a high resistance, low-wattage start-up resistor to be used, to minimize power loss. a 1.5mohm, 0.25w, start-up resistor and a 10uf/25v vdd hold-up capacitor would be sufficient for an ac/dc adapter with a universal input range. operating current the required operating current has been reduced to 4ma. this results in higher efficiency and reduces the vdd hold-up capacitance requirement. green-mode operation. the proprietary green-mode function provides off-time modulation to continuously decrease the pwm frequency under light-load conditions. to avoid acoustic-noise problem, the minimum pwm frequency set above 22khz. this green-mode function dramatically reduces power consumption under light-load and zero- load conditions. power supplies using a IK3401 controller can easily meet even the most restrictive international regulations regarding standby power consumption. oscillator operation a resistor connected from the ri pin to gnd pin generates a constant current source for the IK3401 controller. this current is used to determinate the center pwm frequency. using a 26kohm resistor ri results in a corresponding 65khz pwm frequency. the relationship between ri and switching frequency is: the range of the pwm oscillation frequency is designed as 47khz~109khz. IK3401 also integrates frequency hopping function internally. the frequency variation ranges from around 62khz to 68khz for a center frequency 65khz. the frequency hopping function helps reduce emi emission of a power supply with minimum line filters. leading edge blanking each time the power mosfet is switched on, a turn-on spike will inevitably occur at the sense-resistor. to avoid premature termination of the switching pulse, a leading-edge blanking time is build in. during this blanking period, the current-limit comparator is disabled, and it cannot switch off the gate drive. under-voltage lockout (uvlo) the turn-on/turn-off thresholds are fixed internally at 16.5v/10.5v. to enable a IK3401 controller during start-up, the hold-up capacitor must first be charged to 16.5v through the start-up resistor. the hold-up capacitor will continue to supply vdd before energy can be delivered from the auxiliary winding of the main transformer. vdd must not drop below 1035v during this start-up process. this uvlo hysteresis window ensures that the hold-up capacitor can adequately supply vdd during start-up. gate output/soft driving the IK3401 bicmos output stage is a fast totem pole gate driver. cross-conduction has been avoided to minimize heat dissipation, increase efficiency, and enhance reliability. the output driver is clamped by an internal 18v zener diode in order to protect the power mosfet transistors from any harmful over- voltage gate signals. a soft driving waveform is implemented to minimize emi. slope compensation the sensed voltage across the current sense resistor is used for peak-current-mode control and cycle-by-cycle current limiting. the build-in slope compensation function improves power supply stability and prevents peak- current-mode control from causing sub- harmonic oscillations. within every switching cycle, the IK3401 controller produces a positively sloped, synchronized ramp signal.
technical data rev 00 constant output power limit when the sense voltage, across the sense resistor rs, reaches the threshold voltage, around 0.85v, the output gate drive will be turned off after a small delay t pd. this delay will introduce an additional current proportional to t pd* vin/lp . since the delay is nearly constant regardless of the input voltage vin . higher input voltage will result in a larger additional current and hence the output power limit is also higher than under low input line voltage. to compensate this variation for wide ac input range, a saw- tooth power-limiter is designed to solve the unequal power-limit problem. the power limiter is designed as positive ramp signal and is fed to the inverting input of the ocp comparator. this results in a lower current limit at high-line inouts than at low-line inputs. vdd over-voltage protection vdd over-voltage protection has been built in to prevent damage voltage conditions. when the voltage vdd exceeds the internal threshold due to abnormal conditions, pwm output wil be latched off. over-voltage conditions are usually caused by open feedback loops. limited power control the fb voltage will increase every time the output of the power supply is shorted or over-loaded. if the fb voltage remains higher than a built-in threshold for longer than t d-olp, pwm output will then be turned off. as pwm output is turned off, the supply voltage vdd will also begin decreasing. when vdd goes below the turn-off threshold (eg, 10.5v) the controller will be totally shut down. vdd will be charged up to the turn-on threshold voltage of 16.5v through the start-up resistor until pwm output is restarted. this protection feature will continue to be activated as long as the over-loading condition persists. this will prevent the power supply from overheating due to over loading conditions. protection latch circuit for the IK3401 family, the built-in latch function provides a versatile protection feature that does not require external components. to reset the latch circuit, it is necessary to disconnect the ac line voltage of the power supply. over temperature protection IK3401 has internal function of over temperature protection. noise immunity noise from the current sense or the control signal may cause significant puls width jitter, particulary in continuous- conduction mode. slope compensation helps alleviate this problem. good placement and layout practices should be followed. the designer should avoiding long pcb traces and component leads. compensation and filter components should be located near the IK3401. finally, increasing the power-mos gate resistance is advised.
IK3401 rev. 00 reference application circuit bom
IK3401 rev. 00 package outline dimension n suffix plastic dip (ms ? 001ba) symbol min max a 8.51 10.16 b 6.1 7.11 c 5.33 d 0.36 0.56 f 1.14 1.78 g h j 0 10 k 2.92 3.81 notes: l 7.62 8.26 1. dimensions ?a?, ?b? do not include mold flash or protrusions. m 0.2 0.36 maximum mold flash or protrusions 0.25 mm (0.010) per side. n 0.38 d suffix soic (ms - 012aa) symbol min max a 4.8 5 b 3.8 4 c 1.35 1.75 d 0.33 0.51 f 0.4 1.27 g h j 0 8 notes: k 0.1 0.25 1. dimensions a and b do not include mold flash or protrusion. m 0.19 0.25 2. maximum mold flash or protrusion 0.15 mm (0.006) per side p 5.8 6.2 for a; for b ? 0.25 mm (0.010) per s ide. r 0.25 0.5 1.27 5.72 di mens i on, mm di mens i on, mm 2.54 7.62 a b h c k cm j f m p g d r x 45 seating plane 0.25 (0.010) m t -t- 1 8 4 5 l h m j a b f g d seating plane n k 0.25 (0.010) m t -t- c 1 8 4 5

▲Up To Search▲

Price & Availability of IK3401

	To Download IK3401 Datasheet File
If you can't view the Datasheet, Please click here to try to view without PDF Reader .