LT3750A Capacitor Charger Controller FEATURES DESCRIPTION n Charges Any Size Capacitor The LT 3750A is a flyback converter designed to rapidly n Easily Adjustable Output Voltage charge large capacitors to a user-adjustable target volt- n Drives High Current NMOS FETs age. A patented boundary mode control scheme* mini- n Primary-Side SenseNo Output Voltage Divider mizes transition losses and reduces transformer size. The Necessary transformer turns ratio and two external resistors easily n Wide Input Range: 3V to 24V adjust the output voltage.* A low 78mV current sense n Drives Gate to V 2V accurately limits peak switch current and also helps to CC n Available in 10-Lead MS Package maximize efficiency. With a wide input voltage range, the LT3750A can operate from a variety of power sources. A typical application can charge a 100F capacitor to 300V APPLICATIONS in less than 300ms. n Emergency Warning Beacons The CHARGE pin gives full control of the LT3750A to the n Professional Photoflash Systems user. The DONE pin indicates when the capacitor has n Security/Inventory Control Systems reached its programmed value and the part has stopped n High Voltage Power Supply charging. n Electric Fences All registered trademarks and trademarks are the property of their respective owners. n Detonators *Protected by U.S. patents, including 6518733, 6636021. TYPICAL APPLICATION 300V, 6A Capacitor Charger T1 D1 1:10 V V TRANS OUT 6A Charge Time 300V 56F 10F 300 2 + V = 18V 100F TRANS 250 V TRANS 60.4k V = 6V V CC TRANS V RV CC OUT 12V 200 100k 10F V = 12V TRANS 43k DONE RDCM 150 LT3750A OFF ON CHARGE GATE M1 100 SOURCE 50 GND RBG 0 12m 0 0.1 0.2 0.3 0.4 0.5 2.49k 100pF TIME (SECONDS) 3750a TA03c 3750a TA01a Rev. 0 1 Document Feedback For more information www.analog.com V (V) OUTLT3750A ABSOLUTE MAXIMUM RATINGS PIN CONFIGURATION (Note 1) TOP VIEW V , V , GATE, DONE, CHARGE ........................24V CC TRANS V 1 10 RBG TRANS RBG .........................................................................1.5V DONE 2 9 RV OUT CHARGE 3 8 RDCM SOURCE ......................................................................1V V 4 7 GATE CC Current into RDCM Pin........................................... 1mA GND 5 6 SOURCE MS PACKAGE Current into RV Pin .......................................... 1mA OUT 10-LEAD PLASTIC MSOP Current into DONE Pin ........................................... 1mA T = 125C, = 160C/W JMAX JA Operating Temperature Range (Note 2)....40C to 85C Storage Temperature Range .................. 65C to 150C ORDER INFORMATION LEAD FREE FINISH TAPE AND REEL PART MARKING PACKAGE DESCRIPTION TEMPERATURE RANGE LT3750AEMS PBF LT3750AEMS TRPBF LTHNS 10-Lead Plastic MSOP 40C to 85C Contact the factory for parts specified with wider operating temperature ranges. Tape and reel specifications. Some packages are available in 500 unit reels through designated sales channels with TRMPBF suffix. ELECTRICAL CHARACTERISTICSThe l denotes the specifications which apply over the full operating temperature range, otherwise specifications are at T = 25C. V = V = 5V unless otherwise specified. A CC TRANS PARAMETER CONDITIONS MIN TYP MAX UNITS Minimum V l 2.8 3 V CC Minimum V l 2.5 3 V TRANS V Quiescent Current Not Switching, CHARGE = 5V 1.6 2.5 mA CC Not Switching, CHARGE = 0V 1 A V Quiescent Current Not Switching, CHARGE = 5V 140 250 A TRANS Not Switching, CHARGE = 0V 1 A CHARGE Pin Current CHARGE = 24V 24 A CHARGE = 5V 19 A 1 CHARGE = 0V A CHARGE Pin Enable Voltage l 0.87 1.1 V l CHARGE Pin Disable Voltage DC Threshold 0.2 0.6 V l Dynamic Threshold (Note 3) 30 60 mV Minimum CHARGE Pin Low Time HighLowHigh 20 s l V Comparator Trip Voltage Measured RBG Pin 1.215 1.24 1.265 V OUT V Comparator Overdrive 1s Pulse Width, Measured on RBG Pin 30 mV OUT RBG Pin Bias Current RBG = 1.2V 70 500 nA DCM Comparator Trip Voltage Measured as V V , R = 43k (Note 4) l 5 36 80 mV DRAIN TRANS DCM l Current Limit Comparator Trip Voltage 68 78 88 mV DONE Output Signal High 100k to 5V 4.9 5 V DONE Output Signal Low 100k to 5V 0.1 0.2 V DONE Pin Leakage Current DONE = 2.5V 0.2 A NMOS Minimum On Time 0.6 s Rev. 0 2 For more information www.analog.com