LT1509 Power Factor and PWM Controller DESCRIPTION FEATURES n PFC and PWM Single Chip Solution The LT 1509 is a complete solution for universal off-line n Synchronized Operation up to 300kHz switching power supplies utilizing active power factor n 99% Power Factor over 20:1 Load Current Range correction. The PFC section is identical to the LT1248 PFC n Current Mode PWM controller except the EN/SYNC pin is removed because n Instantaneous Overvoltage Protection PFC and PWM are synchronized internally. n Dedicated Overvoltage Protection (OVP Pin) The current mode PWM section (the LT1508 is the volt- n Minimal Line Current Dead Zone age-mode counterpart) contains all the primary side func- n Typical 250A Start-Up Supply Current tions to convert the PFC preregulated high voltage output n Line Switching Noise Filter to an isolated low voltage output. The PWM duty cycle is n Low Quiescent Current: 13mA internally limited to 47% (maximum 50%) to prevent n Fast 2A Peak Current Gate Drivers transformer saturation. PWM soft start begins when PFC n Separate Soft Start Controls output reaches the preset voltage. In the event of brief line U loss, the PWM will be shut off when the PFC output voltage APPLICATIONS drops below 73% of the preset value. n Universal Power Factor Corrected Power Supplies , LTC and LT are registered trademarks of Linear Technology Corporation. and Preregulators BLOCK DIAGRAM VA V M I CA GND1 PK V OUT REF OUT SENSE OUT LIM CC 7.5V 10 12 8 7 6 3 5 17 V REF V + CC RUN 7A 16V TO 10V 2.2V + M1 V SENSE 14 I A I CA M EA 2 + I I R A B + 7.5V I = 25k M I AC 2 200A RQ I B GTDR1 9 RUN S + 1 7.9V + + 0.7V OVP OSC 16V 11 GND2 14A 2 SS1 16 4 15 C R SET SET + CL 1V 55% + DELAY 1.2V R 7V to + 14A + 4.7V PWM0K S Q SS2 GTDR2 13 20 R 50A 200ns 19 18 16V BLANKING NOTE: PWM PULSE IS DELAYED BY 55% DUTY CYCLE AFTER PFC PULSE RAMP V C 1500 BD01 1 + + W ULT1509 DESCRIPTION By using fixed high frequency PWM current averaging the multiplier. Line current dead zone is minimized with without the need for slope compensation, the LT1509 low bias voltage at the current input to the multiplier. achieves far lower line current distortion with a smaller The LT1509 provides many protection features including magnetic element than systems that use either peak peak current limiting and overvoltage protection. Imple- current detection, or zero current switching approach, in mented with a very high speed process, the LT1509 can be both continuous and discontinuous modes of operation. operated at frequencies as high as 300kHz. The LT1509 also provides filtering capability to reject line switching noise which can cause instability when fed into ABSOLUTE MAXIMUM RATINGS PACKAGE/ORDER INFORMATION Supply Voltage ........................................................ 27V ORDER PART TOP VIEW GTDR Current Continuous ...................................... 0.5A NUMBER GTDR1 1 20 GTDR2 GTDR Output Energy ................................................ 5J GND2 2 19 RAMP LT1509CN I , R , PK Input Current.............................. 20mA AC SET LIM GND1 3 18 V C LT1509CSW V , OVP Input Voltage .................................... V SENSE MAX C 4 17 V SET CC LT1509IN RAMP, V Input Voltage ............................................ 8V C PK 5 16 SS1 LIM LT1509ISW I , M Input Current ................................... 5mA CA 6 SENSE OUT 15 R OUT SET Operating Junction Temperature Range I 7 14 V SENSE SENSE M 8 Commercial ........................................... 0C to 100C 13 SS2 OUT I 9 12 V Industrial .......................................... 40C to 125C AC REF VA 10 11 OVP OUT Thermal Resistance (Junction-to-Ambient) N Package ................................................... 100C/W N PACKAGE SW PACKAGE 20-LEAD PDIP 20-LEAD PLASTIC SO WIDE SW Package ................................................ 120C/W T = 125C, = 100C/ W (N) JMAX JA T = 125C, = 120C/ W (SW) JMAX JA Consult factory for Military grade parts. ELECTRICAL CHARACTERISTICS Maximum operating voltage (V ) = 25V, V = 18V, R = 15k to GND, C = 1nF to GND, I = 100A, I = 0V, CA = 3.5V, MAX CC SET SET AC SENSE OUT VA = 5V, OVP = V . No load on any outputs unless otherwise noted. OUT REF PARAMETER CONDITIONS MIN TYP MAX UNITS Overall Supply Current (V in Undervoltage Lockout) V = Lockout Voltage 0.2V l 0.25 0.45 mA CC CC Supply Current On 11.5V V V l 13 19 mA CC MAX V Turn-On Threshold (Undervoltage Lockout) l 15.5 16.5 17.5 V CC V Turn-Off Threshold l 9.5 10.5 11.5 V CC Voltage Amplifier (PFC Section) Voltage Amp Offset VA = 3.5V l 10 10 mV OUT Input Bias Current V = 0V to 7V l 25 250 nA SENSE Voltage Gain 70 100 dB Voltage Amp Unity-Gain Bandwidth 3 MHz Voltage Amp Output High (Internally Clamped) l 11.3 13.3 V Voltage Amp Output Low l 1.1 2 V Voltage Amp Short-Circuit Current VA = 0V l 3 8 17 mA OUT 2 U W U U WWW U