LINEAR LTC360X Manual
Contents
1. fault conditions is under full control of the analog feed Linear Technology Magazine September 2008 back loops which guarantees charging remains suspended until the internal feedback loops respond coherently and report the need to supply current to the load to maintain proper voltage or current regulation Conclusion The LTC4009 family integrates a full set of charger building blocks in a small PCB footprint The result is a high power battery charger IC with high precision and a full set of monitoring and fault handling features The LTC4009 provides adjustable output voltage control with a simple external user programmed resistive voltage divider As such itis suitable as a general purpose charger that works with multiple battery chemistries and supercaps It offers direct control over the entire charge process facilitating implementation of a wide range of charge termination algorithms with an external microprocessor The LTC4009 1 and LTC4009 2 feature pin programmable output voltage for common lithium ion or lithium polymer battery pack configu rations with one to four series cells For these chemistries the number of precision external application compo nents is reduced without sacrificing accuracy Both 4 1V cell LTC4009 1 and 4 2V cell LTC4009 2 options are available allowing the user to balance capacity and safety per the demands of the application 7 332. LI DESIGN IDEAS 32Vin Synchronous Buck Regulators with Integrated FETs Deliver up to 12A from Sub Imm Height Packages by Stephanie Dai and Theo Phillips Introduction Monolithic buck regulators are easy to hook up and they make it possible to squeeze an entire DC DC converter into very tight spaces Although mono lithics are an easy fit they aren t the perfect fit for every application For instance they typically lack the capa bility to efficiently convert high input voltages gt 12V to low voltages at high output currents gt 4A thus leaving the job to a traditional controller IC and external MOSFETs A new family of devices though offers the advantages of monolithics with the low duty cycle and high ef ficiency of discrete components The LTC3608 LTC3609 LTC3610 and LTC3611 are synchronous buck con verters that bring high power density and simplified design to point of load applications With amaximum input of LTC3608 VIN 5V TO 18V Vin C1 TAIYO YUDEN JMK316BJ226ML T Cin TAIYO YUDEN TMK432BJ106MM V Cour TDK C4532X5R107M L1 SUMIDA CDEP85NP R50MC 125 A new family of devices offers the advantages of monolithic DC DC converters with the low duty cycle and high efficiency of discrete components The LTC3608 LTC3609 LTC3610 and LTC3611 are synchronous buck converters that bring high power density and simplified design to point of load applications 32V they utilize current mode c
3. le 1 Integrated MOSFET buck regulators DESIGN IDEAS LY 90 Vin 12V 35 FREQ 550kHz EFFICIENCY 3 0 01 0 1 1 10 LOAD CURRENT A Figure 2 Efficiencies for a typical LTC3608 application in discontinuous conduction mode DCM and continuous conduction mode CCM good fit in everything from low power portable device applications such as notebook and palmtop computers to high power industrial distributed power systems 7 LTC3610 LTC3611 LTC3608 LTC3609 PV iy Max 24V 32V 18V 32V ILoap Max 12A 10A 8A 6A Package 9mm x 9mm x 0 9mm 9mm x 9mm x 0 9mm 7mm x 8mm x 0 9mm 7mm x 8mm x 0 9mm g 64 pin 64 pin 52 pin 52 pin Roson Top FET 12MQ 15MQ 14mQ 19mQ Ros on Bottom FET 6 5mQ 9mQ 8m 12MQ LTC4009 continued from page 20 LTC4009 family monitors the voltage across the input blocking diode for unexpected voltage reversal Initial startup restarts from fault conditions and charge current reduction during input current limit are also carefully controlled to avoid producing reverse current All members of the family provide an input current limit flag to tell the system when the adapter is running at over 95 of its current capacity Finally each IC features internal over temperature protection to pre vent silicon damage during elevated thermal operation Recovery fromall
4. ontrol up to a 2MHz switching frequency deliver up to 12A of load current and KEEP POWER GROUND AND SIGNAL GROUND SEPARATE CONNECT AT ONE POINT L pono SGND Figure 1 Typical application of the LTC3608 32 are packaged in thermally enhanced packages less than 1mm in height A typical application of the LTC3608 is shown in Figure 1 Features The LTC3608 LTC3609 LTC3610 and LTC3611 integrate high performance synchronous buck controllers with super low Rpsjony DMOS MOSFETs to produce compact high efficiency converters Figure 2 Two package sizes are available each having a high voltage or high current option Table 1 Each device features a sub 100ns on time allowing very low duty cycle operation and high switching frequency The current mode control architecture of these parts simplifies tuning of loop stability and allows excellent transient response with a variety of output capacitor types in cluding all ceramic output capacitor applications The LTC3610 can operate in forced continuous mode which provides the lowest possible output ripple and EMI or discontinuous mode which has better light load efficiency because inductor current is not allowed to reverse Current into the Ion pin sets the on time a resistor Roy from Vyto the Ion pin reduces on time as Vy rises thus limiting changes in switching frequency Furthermore response toa load step can bevery fast since the loop does not have to wai
5. t for an oscillator pulse before the top switch is turned on and current begins increasing The current limit which is inferred from the maximum allowable sense voltage across the on resistance of the bottom FET can be adjusted by applying a voltage to the Vpng pin Maximum load current limits for each Linear Technology Magazine September 2008 part are shown in Table 1 Soft start and latch off functions are controlled by the RUN SS pin preventing inrush current and current overshoot during startup and providing the option of latch off if an under voltage or short circuit is presented An open drain power good pin monitors the output and pulls low if the output voltage is 10 from the regulation point Conclusion The LTC3608 LTC3609 LTC3610 and LTC3611 buck regulators of fer the efficiency and power output capability of separate controller discrete MOSFET solutions with the ease of use and space saving advantages of traditional MOSFET on the die monolithics These parts also yield higher efficiencies than nh IL 5A DIV Vour F 200mV DIV Pr pee LOAD STEP 1A 8A Vin 12V Vout 1 2V Fi V Figure 3 Transient response for the typical LTC3608 application represented in Figure 1 with a load step of 1A to 8A traditional monolithic solutions They conserve power save space and simplify power designs They reduce discrete components over control ler based solutions making them a Tab
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LINEAR LTC360X Manual